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dian
07-22-2014, 01:08 PM
i have many cars. i have two cherokees, 15 years old, they weight 1600 kg. i have a mercedes e50, 15 years old, its 1600 kg. it has 360 hp.

today i saw a bmw, a really small car, at the dealer. i believe it was a 135x. it said 320 hp. i thought this must be a rocket, so i walked over and checked it out. its 1600 kg. so slower than my e50.

why are new cars so heavy? one would think today the copper cables have been reduced. aluminum and composite has replaced steel. sheet metal, they tell me, is stronger and thiner. where does the weight come from? some obsession with rigidity? the e50 is full size and sure rigid enough. the 135x is 4 x 4, but so are my jeeps. i have a porsche that is 900 kg.

any thoughts?

A.K. Boomer
07-22-2014, 01:22 PM
for one you can chalk it up to all the unbelievable amounts of creature comforts and safety crap... and it keeps on piling up,,,
just an AC system can add 150 or more pounds, ABS systems and then you got all your airbags and now seat belt airbags - dvd players all the satellite crap and wiring harnesses as big as you leg, everything adds weight, electric seats with heaters and windows and power locks and all the modules to control all this $hit,,,

cars are not cars anymore my friend - they are big steaming piles of useless crap...

chipmaker4130
07-22-2014, 02:01 PM
Mainly because light is expensive! Just look at the aviation industry. Light and durable is even more expensive. And it is more difficult to repair.

Paul Alciatore
07-22-2014, 02:16 PM
Aluminum? How many aluminum engines and transmissions and differentials are out there? I'm sure there are some, I had an aluminum engine once, but just how many? I mean really, what percentage? And would you buy them? I wouldn't buy a vehicle with an aluminum engine again, at least not without an impossible liberal guarantee (completely free repairs and FREE loaner delivered to my door within 15 minutes, FOREVER).

"...obsession with rigidity..."? You betcha. It is called safety.

And, of course, the creature comforts. My first car had hand cranks for all the windows. Hand cranks! Now every window has an electric motor. Steel, copper, etc. AC, power steering, motorized seats, motorized mirrors even. Not only does all those motors have weight of their own, but they need wiring that my first car did not have. Fewer cables? Probably more. Oh, bigger and heavier battery. The alternators are probably not much heavier than the older generators due to better technology.

Oh, and Americans must have their V8s when a 6 or even a 4 would do.

You asked for it and you got it.

ikdor
07-22-2014, 02:30 PM
Torsional rigidity, sound damping, safety structures, more powerful engines make the entire driveline heavier, everything electrical, hybrid systems, etc.
I for one am happy to trade weight for safety. If you see videos of crashes between old and new vehicles, the new ones drive straight through the old one into the passenger compartment.
Igor

Rosco-P
07-22-2014, 02:33 PM
Oh, and Americans must have their V8s when a 6 or even a 4 would do.

You asked for it and you got it.

You asked for, you got it! Toyota! Can you even order a Toyota, Honda or Nissan with a 4cyl. engine? You forgot to mention power seats, power sunroof(s), entertainment systems for the rear passengers, navigation, crash avoidance, rear hatches that open and close with the push of a button, giant tires and rims on tiny cars, etc. How much of this crap does a person need? If you can't figure out how to drive safely, navigate to you destination, etc., maybe you shouldn't be on the road.

Rustybolt
07-22-2014, 02:36 PM
What would rather have a roll over in?
A prius or a suburbqan?

mars-red
07-22-2014, 02:54 PM
Interesting topic, I've been thinking about this myself, lately. I bought an R32 Golf back in February, and was pretty surprised to learn that it weighs about the same as what we're talking here... 1600kg (3450lb, as I recall) - nearly twice as much as my old '91 Golf, without being a whole lot larger. The engine is heavier for sure, but that's not even scratching the surface. Not only are there plenty of creature comforts that my old Golf didn't have (really, it had none - and I was ok with that), there's a huge amount of sound deadening material everywhere, as well as thicker glass everywhere. Add to that all wheel drive (which you will find on all types of cars these days, from hatchbacks to sedans, to sports cars, not just trucks and SUVs anymore), and that super heavy dual clutch sequential transmission that is starting to become really popular on a lot of cars as well... and before you know it, cars are often twice as heavy as they used to be.

I was always a fan of buying old cars that were lighter, more fun, and easier to work on, but as I get older I'm developing more of an appreciation for some of the extra comfort. A big part of that comfort is the wife no longer complaining that I don't have A/C or power windows. :)

A.K. Boomer
07-22-2014, 03:01 PM
Just love that new lexus commercial (I think it's lexus, but could be anyone of the douche-bag high end overpriced newer japanese POS like acura or infinity)

anyways - it's about their new "crash avoidance" system and this guys driving (I guess you could call it that) and he gets to avert an accident because the cars constantly watching over him, they have him talking to himself and he says something like "wow that was a close one" then five seconds later after he almost rear ends somebody and the car stops it from happening he says something like "didn't see that one coming"

then the overpaid douche-bag narrator that sounds like he should be talking about wild boars on the discovery channel comes on and starts talking about how great the system is and it can do it's job so you can focus on more important things "like driving"

HELLO if you were focusing on more important things like driving in the first place you would not need the POS system,,,

wait a go arssholes --- now the text messages will just get longer and more in depth along with the phone calls,,,IDIOT's can't even comprehend what's going on, same with the morons who actually buy the crap... were going to hell in a bucket people - and there's no better sign of the times than whats happening to the typical automobile,,, and yet somehow the "status" and insecurities rule, somehow you have these moron's behind the wheel thinking that somehow they "made it"

grow a freaking nut sac people...

Black Forest
07-22-2014, 03:39 PM
I like all my creature comforts in my cars. If my AC would stop working I would call a wrecker to tow the car to the dealer!

A.K. Boomer
07-22-2014, 03:52 PM
While AC may not be an absolute necessity it can make driving either physically enjoyable or down right miserable ---

I don't think that's in the same category as some of the other things iv mentioned...

when I talked about it at first it was more to do with how the basics of cars have changed --- my latter rant is how far we've gotten away from even that...

RichR
07-22-2014, 04:07 PM
Hey Boomer. The Fiat 500 is available with an espresso coffee machine. What are your thoughts on that?

A.K. Boomer
07-22-2014, 04:26 PM
well - at least they'll be alert when they die...

ckelloug
07-22-2014, 06:09 PM
Having rolled a prius probably doing about 40mph several years ago, I can say that I walked away with no injuries. The fact that is was a rental on a remote part of a military base on official business proved far more interesting than the crash itself. Since there is a lot more safety engineering in one of these things than an old suburban, id take the prius.

A.K. Boomer
07-22-2014, 06:21 PM
there is no doubt there is things that make good practical sense and thank god we got away from the steering wheels with the metal "bullet" horn button design aimed directly at the driver,

looking back on yesteryears cars it's almost as if they were designed by aliens, and not very intelligent ones at that,,,

but as usual things get pushed too far in the other direction without any thought at all and in fact they are getting so out of hand that many of the so called safety devises can actually get you killed.

and nothing gets me going more than cars that "intervene" that's wrong on so many levels...

mattthemuppet
07-22-2014, 06:35 PM
I had a 91 Mitsubishi Lancer that was one large crumple zone for other cars. It was so flimsy that you could jack up one wheel and the other 3 would stay on the ground, with no way to open (or close) the doors while it was up in the air. Got great mileage (40mpg?) out of it though and when the kids started bawling because they were hot and miserable (this was in Australia) the car was small enough that I could reach both of their window cranks, open all the windows and then not hear them crying over the wind noise.

Ah, those were the days!

M_C
07-22-2014, 07:28 PM
and nothing gets me going more than cars that "intervene" that's wrong on so many levels...

What about trucks?
All new european trucks requiring a new type approval needed crash avoidance systmes as of November last year, with all new trucks needing them by November next year.
http://ec.europa.eu/transport/themes/its/road/application_areas/vehicle_safety_systems_en.htm has a good summary of what's needed in Europe.

Although these systems will intervene, they are all overidable to a certain degree. I know most of the collision avoidance systems issue a warning to the driver several seconds before it thinks it won't be able to stop the vehicle before the obstacle, and will only brake if the driver doesn't respond. Off course if the obstacle suddenly pulls out in front of the lorry, it'll repsond with minimal warning.

A.K. Boomer
07-22-2014, 07:39 PM
It's very dangerous thinking, it yet again further removes people from what they should be doing in the first place, driving.

it is not the direction we should be going,,, look at the stats on how many accidents are simply from people not paying attention it's staggering, and now they will have a reason to remove themselves even further, it's wrong - it's dead wrong...

we are going to hell in a bucket... but don't worry - it will steer itself...

Bluechips
07-22-2014, 08:33 PM
we are going to hell in a bucket... but don't worry - it will steer itself...

If Google has their way we'll have driverless cars sooner than later. If the PR hype is to be believed, they're "almost" perfected. One of the prototypes that is being kicked around won't even have driver controls. No way to take over if the computer screws up. Just sit there dumbly tweeting about your impending crash on your cell phone while your car drives into a crowd or off a cliff.

boslab
07-22-2014, 09:09 PM
There are so many different steels in a car its amazing, the biggest driving force in Europe is safety and corrosion followed by economy, to satisfy safety there are as pointed out "crumple" zones, to acheive that there must be a stronger steel either side of a sacrificial area of weaker steel, HSLA, high strength micro alloyed being the favourite, the steel is thicker and heat treated, temper rolled amongst other things, all adds weight, then there are the decorative panels, deep draught pressings, designers require some very curvy bits these days but as they are exposed surfaces the extended corrosion warrenty of anything up to six or eight years requires a steel that dosent succumb to rust, the chosen material is usually an ultra low carbon steel, truthfully its not even steel! The carbon content is below 0.0035, there is more phos at 0.022 max, technically its Titanium Iron not steel, its soft as poo and needs to be thicker
A lot of pressings are made of several steels laser welded together like dressmaking.
I worked for TATA who also do Jaguar and Land rover, the big plants over here are in the process of dropping steel for Aluminium, great news for the steelmaking section!, all the markes are destined for Aluminium over the next few years, we even did some test rollings of aluminium slabs on the steel rolling mill, turns out to be very sucessful, the high speed mill is built for much higher rolling forces with steel so its rolling rate and speed was much higher than processing a steel slab, all aimed for weight saving and economy saving on fuel, sensibly they are trying to cut down on plastic! VAG are very much heading the same way also BMW.
It seems that engines and the rest arent getting much lighter or better, simple reasoning should tell you that they can be made lighter and more economic, but its not happening i wonder why? Lol
MPG isnt improving much, and hasent changed for decades, it could, i have seen ceramic and plastic engines, quater of the weight but as yet none have appeared on the high street, ok piston crowns, valves and cranks were steel, bore liners were ceramic.
It would hurt the fuel industry if cars got suddenly lighter and did not use as much fuel, methinks a hidden agenda lives there somewhare?
How about steam powered cars!
Mark

PStechPaul
07-22-2014, 09:49 PM
I am a firm believer in electric cars and I have been active on the DIYelectricCar forum for several years now. I am lucky to have one of the last Saturns that was still built for economy and I average 35 MPG and regularly get 45+ MPG on long trips, so for now it is not really economically viable for me to buy or build an EV. It is sad to see how the resurging HP wars of the 2002+ model years changed the emphasis from frugality, efficiency, and conservation, to "zoom-zoom" and "aggression, in it's most elegant form". Car manufacturers (probably in collusion with gas companies) built more models with higher power and emphasized the thrill of driving aggressively and competiively and ridiculed smaller cars as being silly and effeminate. There is an obvious appeal to testosterone and sex appeal that is very effective when applied to teenage drivers and guys with middle-age insecurity, and they are probably the largest segment of the market.

Now they are adding other features such as automatic parallel parking that I hope is not allowed for driver's tests. I am glad that everything in my car is manual and I can tell by feel or sound when the brakes are sticky or the steering feels imprecise. I would hate to drive a car where having the ignition turn off disables everything including the shifter and parking (emergency) brake, or where a dead battery might mean I can't unlock the doors or roll down a window. It's bad enough that my car is controlled by a microcomputer, but they seem to be reliable and usually their "limp home" backup systems work OK.

AD5MB
07-22-2014, 10:26 PM
Oh, and Americans must have their V8s when a 6 or even a 4 would do.

just one state west of you, we got rockies

if you drive the speed limit you are a menace to traffic

and everybody is pulling some kind of trailer.

you just try pulling a trailer through the rockies at 70 with a 4 cylinder

RichR
07-22-2014, 10:47 PM
It's very dangerous thinking, it yet again further removes people from what they should be doing in the first place, driving.

it is not the direction we should be going,,, look at the stats on how many accidents are simply from people not paying attention it's staggering, and now they will have a reason to remove themselves even further, it's wrong - it's dead wrong...

we are going to hell in a bucket... but don't worry - it will steer itself...

Absolutely correct. The last thing we need is to tell people it's OK to pay even less attention to what's going on around them than they already do. And you
just know there will those that want to play games. Can you picture two dumb asses playing chicken to see whose collision avoidance system flinches first?

PStechPaul
07-22-2014, 10:55 PM
Wanting to be able to drive 70+ MPH on steep grades with a heavy trailer is typical of "American Greed" and the obsession with power and wanting to go somewhere as fast as possible without enjoying the experience (and be safer) by slowing down. People seem to be hell bent on getting somewhere with their RV or camper and then setting up and spending most of the time cooped up in it watching TV, playing games, or sleeping with the A/C full blast. This is another unfortunate lifestyle choice that has been promoted by "Big Iron" in Detroit and the gas companies. There will probably come a day when most long range travel (and heavy transport) is once again the dominion of railways which are many times more efficient, and provide much better safety for everyone by staying off the roads. And it will also provide more true enjoyment by allowing a relaxing ride with opportunities for enjoying the scenery (or playing games/watching entertainment if you prefer), rather than getting stressed out on long drives cursing traffic and promoting road rage and "accidents".

kf2qd
07-22-2014, 11:03 PM
If Google has their way we'll have driverless cars sooner than later. If the PR hype is to be believed, they're "almost" perfected. One of the prototypes that is being kicked around won't even have driver controls. No way to take over if the computer screws up. Just sit there dumbly tweeting about your impending crash on your cell phone while your car drives into a crowd or off a cliff.

Awesome Idea. NOT! So we are going to have these cars driving around with software, created by fallible humans, and we are to assume that those programmers made no mistakes... I am a programmer and I don't believe it can be done. The more lines of code, the more unknowns that are hidden there, and the more people involved that don't have a clue what was happening in other portions of the code...

PStechPaul
07-22-2014, 11:33 PM
It can probably be proven that the reliability of a properly designed autonomous road vehicle is many times less likely to fail than a human driver, especially with the many distractions such as cell phones, GPS, and entertainment systems. This would be especially true if all cars were so equipped and required for operation on main highways. It is usually a combination of idiotic and aggressive driving combined with inattention and distraction of other drivers that cause most serious accidents. But really the solution is eliminating most cars and trucks on highways, and using rail transport, which can also ferry vehicles to their destinations much more efficiently than driving them.

Willy
07-23-2014, 12:07 AM
.........
.....and nothing gets me going more than cars that "intervene" that's wrong on so many levels...

Expect this trend to continue.
We live in a world where everyone expects someone else to be responsible for our well being.
Instead of addressing the root cause of the problem we find it easier to legislate safety. This type of thinking distances us from the problem. As long as the act of obtaining a drivers license biggest hurdle is coughing up the examination fee we will see more carnage and increasing knee-jerk reactions in order to deal with the issue that conservatively costs the US economy alone 1 trillion dollars (http://www.rmiia.org/auto/traffic_safety/Cost_of_crashes.asp)! That's a thousand billion.
There is no a way to put all of the untold personal suffering in perspective.

Unfortunately this problem won't go away even with intensive driver training and licensing procedures. How do you instill in people that strict attention to what they are doing behind the wheel is paramount above all else? How do you change attitudes? How do you legislate sanity?:confused:
Rant off.

On a note more in keeping with how increasing vehicle weight affects collision survivability you may find this report interesting. I don't expect everyone to read all of this report as it does get somewhat technical in it's scope but if nothing else at least read the first 2-3 page introduction. This points out that in a two vehicle collision, being hit by a vehicle 1,000 lbs. heavier, the fatality rate increases approximately 47% to those in the lighter vehicle.

Pounds That Kill: The External Costs of Vehicle Weight
(http://are.berkeley.edu/~mlanderson/pdf/anderson_auffhammer.pdf)

mattthemuppet
07-23-2014, 01:25 AM
The push towards more driver aids is necessary because most drivers are crap and even good ones are fallable. More collision avoidance systems equals fewer deaths, it's as simple as that. All the arguments for better driver training have had their decades to prove themselves and the key driver towards lower deaths had been increases in vehicle safety and systems, not better drivers. It may seem unpalatable to people who think themselves excellent drivers ( pretty much everyone), but that's just the way it is.

Sun God
07-23-2014, 01:38 AM
Good point Willy - in reality the average family car could probably weigh 6-800kg and be ultra fuel efficient due to weight savings. The catch is the comparative survivability of the lightweight car is drastically lower than a heavier vehicle in a multi-vehicle collision (I don't believe the same contention applies to single vehicle or one stationary vehicle collisions); so putting yourself on the road in a very efficient, ultra lightweight vehicle is putting yourself at a safety disadvantage compared to other road users - and then there is the unavoidable mass of heavy vehicles, which is unlikely to reduce commensurately.

The vast majority of passenger vehicles could probably be made of a light aluminium body over a small steel rolling chassis for fatigue strength, should they only be required to be engineered for comparable survivability with vehicles of similar type, weight, and construction. Such a lightweight vehicle would benefit hugely from hybrid diesel/electric power, and would have amazing performance to boot. But get into a multi-vehicle accident with a light truck or heavier, and they'll be scraping you out of the interior with a frosting spatula...

PStechPaul
07-23-2014, 02:07 AM
Maybe small efficient vehicles should be equipped with bumpers made of reactive armor (http://en.wikipedia.org/wiki/Reactive_armour). It might neutraliize some of the kinetic energy of a larger impacting vehicle, and if nothing else, may guarantee that they suffer a similar fate to your own. MAD (http://en.wikipedia.org/wiki/Mutual_assured_destruction)?

I also once thought that an ejector seat might be a good safety device. But if both drivers have them, and they have a head-on collision, they may both collide with each other in mid-air. Something like this has been proposed:
http://www.sumobrain.com/patents/wipo/Easy-ejector-seat-indo-skeletal/WO1999015379.html

(Maybe I had too much beer - I think the hops make me a bit goofy) ;)

MrFluffy
07-23-2014, 04:28 AM
just one state west of you, we got rockies

if you drive the speed limit you are a menace to traffic

and everybody is pulling some kind of trailer.

you just try pulling a trailer through the rockies at 70 with a 4 cylinder

My Mercedes sprinter van with a 2.9 five cylinder turbo diesel can tow a 1.75 box trailer, with another ton inside the load area of the van (well I hope it was a ton officer, it was a entire car) on a "private section of hilly road" at 100mph.
There is also a hill out of calais port which brought my old 2.5d renault master panel van down to 10mph at its top screaming stinking hot with a full load but no trailer. The sprinter with box trailer combo was still doing 60mph at the top of the hill barely phased with the above load and trailer. Its not unknown on a quiet empty motorway or autoroute or autobahn to see one canting along at 115+ mph, which for something with the aerodynamics of a large brick is pretty impressive.

Turbodiesel four's have come a LONG way. And that five cylinder om602 merc engine is epic, its just run in at 180,000 miles too. Its got more torque and power than my v8 powered range rover I had previously.

dian
07-23-2014, 04:38 AM
well, the two vehicles i mentioned have ac, electric everything, the mercedes has seat heaters and 18" wheels. it is still one of the fastest cars on the autobahn and as for sound deadening, you cannot tell, if its idling or not and 240 kmh is a comfortable travelling speed. the jeep will pull a trailer at 70 mph in the mountains easily.

MrSleepy
07-23-2014, 04:43 AM
This video by the uk tv show fifth gear show a crash between a 1980s Renault Espace and a newer version of the same model.

https://www.youtube.com/watch?v=xQS-7heF-og

Is demonstrates why you'd want the newer ,heavier design.

Rob

dian
07-23-2014, 08:03 AM
what happens when the newer, heavier design crashes against another newer, heavier design?

Mike Nash
07-23-2014, 08:23 AM
Wanting to be able to drive 70+ MPH on steep grades with a heavy trailer is typical of "American Greed" and the obsession with power and wanting to go somewhere as fast as possible without enjoying the experience (and be safer) by slowing down.

Or maybe they are just trying to NOT be selfish by NOT inflicting some pokey-butt, traffic congesting, road-rage inducing arbitrary slow speed on all the rest of those sharing the road with them. My fond wish would be to see everyone traveling at the posted speed limit and staying off of each other's bumpers, front OR rear.

Seriously, have you never experienced the craziness that goes on when everyone realizes there is some travel trailer or motorhome ahead approaching a long hill? No one wants to be stuck behind them, resulting in people jerking over in front of the the ones who have sped up so as to not be caught, etc, ad naseum.

wendtmk
07-23-2014, 08:30 AM
Aluminum? How many aluminum engines and transmissions and differentials are out there? I'm sure there are some, I had an aluminum engine once, but just how many? I mean really, what percentage? And would you buy them? I wouldn't buy a vehicle with an aluminum engine again, at least not without an impossible liberal guarantee (completely free repairs and FREE loaner delivered to my door within 15 minutes, FOREVER).

Oh, I don't know about that. Had a 1998 Chebby Z28 Camaro that I traded in this past year that had over 320,000 miles on that aluminum engine.

Mark

J Tiers
07-23-2014, 08:31 AM
If you want the ONE key problem that contributes disproportionately to traffic accidents..... it is the cell phone. Particularly texting...

The cell phone has negated decades of driver training, etc..... If there is a crash now.... around here there is nearly a 50% chance one of the drivers was texting. If an 18 wheeler is involved, it may be as high as 80% chance the driver of the truck was texting.

IIRC, there was a case a few years ago of a COP driving at 120mph to some call while texting..... of course he crashed into some people.

[QUOTE=dian;928331

why are new cars so heavy? [/QUOTE]

"because they can"..... :D

Actually, most cars are lighter than they used to be, taken with comparable vehicles...due to fuel economy requirements. Old US cars from the 60's were often REALLY heavy, with big but often lower power engines, heavy sheet metal, heavy beam frames, etc. Old european cars were lighter..... and smaller.

The "safety crap" (most of which works, and which you would quickly stop calling "crap" if you get clobbered by a drunk driver) is actually a smaller part of the weight. It's being accomplished by improved structural shapes, folded sheet metal, etc that adds relatively little weight relative to it's strength.

Just look at an older car and a newer one.... the older car will often look bare and simplified, like a bicycle next to a full-dress Harley-Davidson. All the stuff you don't see in the old car weighs something.

Some things are new additions for various regulatory issues... door beams for side impact (thanks, I'll keep them, YOU can be the one killed without them if you like), catalytic converters (which are a silly solution, but now universal), etc.

Other stuff is "luxury stuff".

I'd bet that a current model Cadillac generally weighs less than the 1960's finned monstrosity version, and not by just a few kg.

MrFluffy
07-23-2014, 08:50 AM
Not sure its entirely weight/inertia related. From my direct experience I've actually dismantled a espace the same as the red one in that vid after it was written off hitting a jack rabbit at speed (the rabbit splattered the front fibreglass and the cost to replace exceeded the value of it), and murdered a mk2 with the digger getting the transaxle out the easy way for a kitcar (un1 transmission on certain models, its very sort after in race/kitcar circles) its mostly a fibreglass cover over a spaceframe with very very little of frontal protection, I think if it hit a contempary it would have crumpled in the same way too and that impact is exactly the least protected of impact areas on the car, so a bit of a rigged video for the shock factor also ;)
The builders were matra, not Renault despite the badge and the mk3 espace had put weight on vs the mk1 featured and still had the spaceframe. The mk iV espace which hit it, was the first to discard the spaceframe concept and go back to steel unibody construction because it was cheaper to make on a renault production line as the iv was the first truly renault built espace, and gained weight as a result of the construction changes to a cheaper method. Pity they didn't reduce the price when they rebadged it the "grand espace" to reflect this, but it went UP in price if I recall.

Other stuff like that, the bedford rascal midi vans, theres not much in front of the forward mounted driver, and most accident recoveries involve cutting the drivers crushed legs out the remains of the cab as a result. VW buses also, in fact anything which puts you ahead or astride the engine.

My wife has a ford galaxy (vw sharan/seat alabhrama etc) and that has been engineered to be much more robust in this kind of impact. Most of the weight is from the geegaws it has though, dual aircon circuits for climate control zones inside, 7 removable seats, electric mirros and windows right through, cup holders everywhere etc.

thaiguzzi
07-23-2014, 09:39 AM
Just love that new lexus commercial (I think it's lexus, but could be anyone of the douche-bag high end overpriced newer japanese POS like acura or infinity)

anyways - it's about their new "crash avoidance" system and this guys driving (I guess you could call it that) and he gets to avert an accident because the cars constantly watching over him, they have him talking to himself and he says something like "wow that was a close one" then five seconds later after he almost rear ends somebody and the car stops it from happening he says something like "didn't see that one coming"

then the overpaid douche-bag narrator that sounds like he should be talking about wild boars on the discovery channel comes on and starts talking about how great the system is and it can do it's job so you can focus on more important things "like driving"

HELLO if you were focusing on more important things like driving in the first place you would not need the POS system,,,

wait a go arssholes --- now the text messages will just get longer and more in depth along with the phone calls,,,IDIOT's can't even comprehend what's going on, same with the morons who actually buy the crap... were going to hell in a bucket people - and there's no better sign of the times than whats happening to the typical automobile,,, and yet somehow the "status" and insecurities rule, somehow you have these moron's behind the wheel thinking that somehow they "made it"

grow a freaking nut sac people...

+1.
You, AK, are the Man !

mixdenny
07-23-2014, 10:33 AM
Well, there are light cars. I have a first generation Scion Xb, the little box, and love it. It weighs 2400 lbs (1090 kg) and has 102 hp. It handles like a sports car and gets an *average* of 36 mpg. It holds a lot of stuff, I use it for construction work. In the past year I have bought a 48" brake and 36" foot shear at auction and brought them home inside. (Separate auctions). Another time I carried (2) Sanford surface grinders with accessories. I recycle lead bullets and regularly haul 500-700 lbs worth of plastic buckets.

It has all the features that are more or less standard in nice cars: power everything, cruise control, traction and stability control. And as boxy as it is, it is the quietest car I have ever driven at speed with the windows down, my preferred way of driving. And the AC will freeze you when I do want it.

When the second generation came out in 2007, they added 450 lbs and 40 hp and ruined the economy.

Dennis

needlenose
07-23-2014, 11:22 AM
we are going to hell in a bucket... but don't worry - it will steer itself...

Lol! ...and avoid any obstacles we attempt to place in it's path to slow it down!

bob_s
07-23-2014, 11:54 AM
Maybe, just because they have to share the roads with semis, b-trains, c-trains, .....

lakeside53
07-23-2014, 12:11 PM
Aluminum? How many aluminum engines and transmissions and differentials are out there? I'm sure there are some, I had an aluminum engine once, but just how many? I mean really, what percentage? And would you buy them? I wouldn't buy a vehicle with an aluminum engine again, at least not without an impossible liberal guarantee (completely free repairs and FREE loaner delivered to my door within 15 minutes, FOREVER).
.

There are so many reliable and long lasting "aluminum" engines and transmissions out there, but I'm guessing you don't buy Japanese.

Just a couple I own - Mazda B series trucks (at least up until they got Ford running gear) have "AL" transmissions. Subaru has all "AL" engines and transmissions. Not unusual to see 250-300k miles on these. I just rebuilt one at 130K miles because of and oil leak, and you could still see the crosshatch on all parts of the bore. Other than preventive replacement of timing related parts, I did nothing other than replace the gaskets. Even the valves and seats were perfect. it's good for another 130k now but I doubt I'll live that long :-)

jdunmyer
07-23-2014, 07:59 PM
But really the solution is eliminating most cars and trucks on highways, and using rail transport, which can also ferry vehicles to their destinations much more efficiently than driving them.


The point isn't efficiency, or we'd stayed with trains and trolleys, etc. An automobile spells FREEDOM for you as an individual, you're not beholden to someone else's schedule.

And the person who says that all this safety stuff leads to people driving less safely is SO full of it. I'd imagine that he removes the guards from his machines to force himself to pay attention and not get his fingers in the belts or gears.

The self-driving cars will no doubt crash because of a software or hardware failure, and there will no doubt be plenty of lawsuits to follow. BUT, they'll save countless lives due to far fewer crashes. Yes, we shouldn't be texting or even talking on cell phones, but which one of us hasn't had at least a close call because of gawking around?

PStechPaul
07-23-2014, 08:39 PM
Of course, efficiency has only recently become a major issue in transportation, because oil has been so cheap and because the oil companies have reportedly been in collusion with car companies to promote bigger, more powerful vehicles, and resultant higher fuel consumption, while marketing it as having fun or proving ones "manhood". And of course, cars have always been a symbol of freedom, and something of an equalizer where almost anyone can purchase enough power to blow anyone else off the road.

Railroads were to some extent disadvantaged when truckers effectively lobbied for greater subsidies, and the fact that it meant a lot more good-paying union jobs compared to those of railroads. There were more public projects to build the Interstate Highway System, while railroads were left on their own, and found it hard to compete. The trucking industry has also been an expression of "freedom", with the new cowboy image of the independent trucker rolling over the country, with more glamour than the well-regulated railroads.

The proliferation of suburban sprawl that began shortly after the war heroes returned from Europe and Asia also contributed to the concept of long commutes in individual cars rather than the pre-war norm of taking public transportation. This was no doubt also encouraged by "Big Oil", and it intensified during the 1950'-1960's flight from increasingly crime ridden cities to the safer enclaves of Suburbia. Public transportation was seen as mostly for poor people, and became unused and impractical for most people.

Now it has become a virtual necessity for national security and global peace to limit our dependence on foreign oil, or that obtained through increasingly dirty and inefficient means, so our "love affair" with cars, especially "muscle cars", is nearing the end. Trucks have become increasingly hazardous on highways shared with others, particularly those with smaller, more efficient vehicles, and it seems logical that long distance heavy hauling should be returned to railroads. This will eliminate a lot of jobs, but that is true for many industries, and we will need to become used to working less and enjoying life more.

As for the illusion of freedom created by the automobile, consider the amount of time and frustration involved in most driving, and that most people would rather be playing electronic games and listening to powerful entertainment systems and chatting on cell phones, while there is not that much scenery to be enjoyed, especially if you're stuck in the rocking chair among a few semis.

Willy
07-23-2014, 09:35 PM
...................
and it seems logical that long distance heavy hauling should be returned to railroads. This will eliminate a lot of jobs, but that is true for many industries, and we will need to become used to working less and enjoying life more........


Well I guess if you think enjoying life more means a life without fresh produce, dairy products and a multitude of other time sensitive products then yeah eliminate trucks.
The logistics of moving freight is a partnership between truck, rail and air freight, they complement each other.
You would be very unpleasantly surprised if one of those legs of this tripod went missing.

The trend to "just in time inventory" and society's thirst for a better way of life is responsible for increased truck traffic, those guys aren't out there just for the joy of being independent cowboys. Your life would be much different than it is now without the convenience and speed of truck freight.
Also, if you think the railways are adverse to accepting subsidies you'd be very wrong.

danlb
07-24-2014, 01:40 AM
You asked for, you got it! Toyota! Can you even order a Toyota, Honda or Nissan with a 4cyl. engine?

Yup.

You can get 4, 6, 8 and hybrids too!

My hybrid has a 4 cyl engine supplemented by the electric motor. My wife's Camry has a bigger engine, but it's still an inline 4.

To add to the weight issue... Similar sized cars.
2010 camry hybrid 3680 lbs
1963 Plymouth Belvedare 3019 lbs

The Plymouth I bought when it was 10 years and 100K miles. I paid 100 dollars for it. It was worn out. The Camry has 85Kmiles and it looks and runs like new. Might it be that they are being built better?

Dan

Spin Doctor
07-24-2014, 06:14 AM
Aluminum? How many aluminum engines and transmissions and differentials are out there? I'm sure there are some, I had an aluminum engine once, but just how many? I mean really, what percentage? And would you buy them? I wouldn't buy a vehicle with an aluminum engine again, at least not without an impossible liberal guarantee (completely free repairs and FREE loaner delivered to my door within 15 minutes, FOREVER).

"...obsession with rigidity..."? You betcha. It is called safety.

And, of course, the creature comforts. My first car had hand cranks for all the windows. Hand cranks! Now every window has an electric motor. Steel, copper, etc. AC, power steering, motorized seats, motorized mirrors even. Not only does all those motors have weight of their own, but they need wiring that my first car did not have. Fewer cables? Probably more. Oh, bigger and heavier battery. The alternators are probably not much heavier than the older generators due to better technology.

Oh, and Americans must have their V8s when a 6 or even a 4 would do.

You asked for it and you got it.

A Vega maybe

J Tiers
07-24-2014, 08:30 AM
"...obsession with rigidity..."? You betcha. It is called safety.



An EXTREMELY FALSE STATEMENT

"Rigid" vehicles transmit ALL the force of the collision DIRECTLY TO YOUR BODY. You must be supported by some sort of harness with some 'give", in order to reduce the "g" forces on you.

A perfectly rigid vehicle would act somewhat like a billiard ball. What you really want is behavior more like a lump of putty..... absorbing the energy over a distance. A proper safe vehicle collapses in a controlled manner, dramatically lowering the "g" forces applied to the cargo (you). It is designed with a "crush zone" outside of the passenger compartment, so that the passenger compartment comes through the crash reasonably well, and the drastic damage is in the "crush zones".

As for the "massive is better" idea.....

1) Massive vehicles get worse mileage

2) Massive vehicles use more material, resources, and cost more, but offer zero advantage as far as the basic idea of traveling from "a" to "b". It's about luxury, and an unconcern about use of resources.... "I can afford it"...

3) Massive vehicles are designed to use the "opposing" car as their "crush zone"... No need to have a crush zone if you can use the other car.... just put in enough to pass the barrier crash testing, proportioned, of course, to the huge mass of the vehicle.... so it's very stiff and smashes lighter weight vehicles flat. One can argue they are DELIBERATELY designed so that the people in the other vehicle involved in the crash are the ones killed.
The massive vehicle is essentially a weapon in the car crash arms race. It would be possible to design vehicles so that they did NOT smash smaller vehicles flat, but this is not done, and the only possible conclusion is that it is deliberate on the part of the designers. Yet another case of the privileges of being rich..... you get to kill the other folks....because you are rich and important....

jdunmyer
07-24-2014, 09:00 AM
Paul,
I don't think things evolved just as you've described: people left the cities because they COULD, largely because of automobiles. Yeah, there are some folks who want to live in a city, but many more prefer a bit more space for a lawn & garden, etc.

If you've been following the industry, you should be aware that we're hardly dependent on "foreign oil" any more. The best way to understand exactly what the situation is with oil or other fuels is to look at the price; gasoline is actually quite inexpensive, relatively speaking. Yeah, I remember gas at $.319/gallon, but that was when I was making $4000.00/year.

I do agree that electric autos are the wave of the future, my daily driver is a Nissan Leaf. But, I can't give up the VW TDI just yet.

As to the original subject of cars being heavier: they last far longer than years ago, require much less routine maintenance, and are far, far safer. Here's a good summation: http://en.wikipedia.org/wiki/List_of_motor_vehicle_deaths_in_U.S._by_year Cliff's Notes show a peak of over 29 deaths/100K population in 1937, down to 26/100K in 1972, falling to <11/100K in 2012. It isn't all due to safer autos, of course, roads are much safer also, and we've clamped down severely on drunk driving.

Royldean
07-24-2014, 11:13 AM
Aluminum? How many aluminum engines and transmissions and differentials are out there? I'm sure there are some, I had an aluminum engine once, but just how many? I mean really, what percentage?

Is this sarcasm? Or are you serious?
http://www.cleveland.com/business/index.ssf/2011/07/automakers_turn_to_aluminum_to.html

That article suggests that over 70% of all new vehicles have aluminum engine blocks. And I would bet that 100% of transmission cases are now aluminum. When was the last time you crawled under a car?

lynnl
07-24-2014, 12:59 PM
I just wrapped up a 2-3 month car shopping odyssey, with the purchase of a Toyota Camry Hybrid. I checked out most of the more common makes and models, and did not encounter one 8 cylinder engine. ... in fact there were very few 6 cylinders, most more powerful models seemed to be turbo charged 4 cylinders.

In their attempts to meet the forthcoming, tightening fleet gas mileage requirements the auto makers are cutting every pound of weight, wherever possible.

This hybrid only has about 450 miles on it, so it's much too soon to offer an informed evaluation, but so far I really like it, especially the quiet smoothness.

danlb
07-24-2014, 07:38 PM
I just wrapped up a 2-3 month car shopping odyssey, with the purchase of a Toyota Camry Hybrid. [ snip ]
This hybrid only has about 450 miles on it, so it's much too soon to offer an informed evaluation, but so far I really like it, especially the quiet smoothness.

I suspect that you will like it. The largest disappointment comes from salesmen who build your expectations so high that the car can't possibly make you happy.

My wife drives from Silicon Valley to San Diego every month in her Camry hybrid. The car is substantial enough that the winds in the central valley don't bother it. It rides smoothly and has had no problems with her habit of driving 90 MPH for hours at a time. About 80K miles on it now.


Maybe part of the heavy car syndrome has to do with plush ride and handling in windy conditions?

Dan

PStechPaul
07-24-2014, 08:51 PM
It is interesting that a semi truck can have a CAFE figure of 6.5-8 MPG. If that is a realistic figure for a car carrier hauling five big SUVs or pickups, which might (even now) get only 22-25 MPG, it is more efficient to transport them by carrier than driving them individually. I think one reason is diesel vs gas, but is likely due to the fact that trucks slow down to 40 MPH or so on steep climbs, while the average Jo wants to be able to tow a boat over a mountain at top speed.

I made an on-line calculator using JavaScript, mostly for analyzing EVs for torque, speed, power, and other metrics, and it may be surprising how much more power is required at 60 MPH as compared to 40. A 9000 kg (20,000 pound) vehicle requires 240 HP on a 5% slope at 100 km/hr (62 MPH), while at 63 km/hr it needs just 148 HP. That's at 1.25 m^2 frontal area, and at four times that, the values are 255 and 152. On a flat road, the requirements are 88 vs 47, and for a small car of 1000 kg (2200 lb), it is 29 vs 10 HP . With an EV, it may be possible to recoup a good portion of the potential energy stored at the crest of the hill, whereas a gas or diesel vehicle cannot do this.

http://enginuitysystems.com/EVCalculator.htm

So, the extra weight of a car with all sorts of safety features and creature comforts is not that big a hit, especially for a hybrid or EV.

A.K. Boomer
07-24-2014, 10:38 PM
The savings is huge no doubt - but there's one thing your forgetting,,, the car "taking the hill on" get's it over with allot quicker,

so even though the consumption rate per second is allot more it's getting it done in just 2/3rds the time frame,,, not trying to totally sour what your stating , just stating that it's not all there is to look at...

danlb
07-25-2014, 12:47 AM
The savings is huge no doubt - but there's one thing your forgetting,,, the car "taking the hill on" get's it over with allot quicker,

so even though the consumption rate per second is allot more it's getting it done in just 2/3rds the time frame,,, not trying to totally sour what your stating , just stating that it's not all there is to look at...

It's taking 50% more power to get there 35% faster. That's a loss according to my math.

Dan

A.K. Boomer
07-25-2014, 01:17 AM
Oh of course - im just saying don't forget to add (or subtract) the time frame... not quite as bad as it originally sounds...

RichR
07-25-2014, 01:31 AM
It's taking 50% more power to get there 35% faster. That's a loss according to my math.

Oh of course - im just saying don't forget to add (or subtract) the time frame... not quite as bad as it originally sounds...
Even that probably does not tell the whole story since it doesn't take into account how efficiently the fuel is being converted into HP in each case. MPG gives
a clearer picture.

Royldean
07-25-2014, 09:13 AM
So, the extra weight of a car with all sorts of safety features and creature comforts is not that big a hit, especially for a hybrid or EV.

For highway cruising, maybe. But I drive to work in stop-and-go.....

A.K. Boomer
07-25-2014, 09:59 AM
It is interesting that a semi truck can have a CAFE figure of 6.5-8 MPG. If that is a realistic figure for a car carrier hauling five big SUVs or pickups, which might (even now) get only 22-25 MPG, it is more efficient to transport them by carrier than driving them individually. I think one reason is diesel vs gas, but is likely due to the fact that trucks slow down to 40 MPH or so on steep climbs, while the average Jo wants to be able to tow a boat over a mountain at top speed.

I made an on-line calculator using JavaScript, mostly for analyzing EVs for torque, speed, power, and other metrics, and it may be surprising how much more power is required at 60 MPH as compared to 40. A 9000 kg (20,000 pound) vehicle requires 240 HP on a 5% slope at 100 km/hr (62 MPH), while at 63 km/hr it needs just 148 HP. That's at 1.25 m^2 frontal area, and at four times that, the values are 255 and 152. On a flat road, the requirements are 88 vs 47, and for a small car of 1000 kg (2200 lb), it is 29 vs 10 HP . With an EV, it may be possible to recoup a good portion of the potential energy stored at the crest of the hill, whereas a gas or diesel vehicle cannot do this.

http://enginuitysystems.com/EVCalculator.htm

So, the extra weight of a car with all sorts of safety features and creature comforts is not that big a hit, especially for a hybrid or EV.


There's important factors to realize with what was wrote in this and also the comment I made earlier as it being "not as bad as one thinks due to the vehicle pulling the hill and ""getting it over with""

Im talking only about the effort of what it takes to climb the pass, as most all of the extra ponies you put into it is rewarded in work benefiting a reduced corresponding time frame,

So keep in mind (Danlb) that the calculations that PStech wrote down in the above statement is not in a "pure form" for just the effort it takes to pull the hill, as he has also included the wind drag and frontal area of the vehicle,,,

This is a completely different beast, as it more equates to "double the speed --- quadruple the force"

another words, when it comes to air drag, want to go twice as fast? then it's going to cost you 4 times the horsepower and this is where in the name of economy things eat it REALLY REALLY bad --- for it does not matter if you get there twice as fast if your engine is sucking on a garden hose and using 4 times the amount of fuel whilst doing so,,,

in comparison the hill is not that way, and the further the speed gets reduced because of it the more the tables shift in the direction of being rewarded for your extra work you put into it,
take an extreme example of an overloaded vehicle, yes the same rules will still apply to the air drag if you go from 8 mph to 16, but if it only takes 1/3hp to go 8 then tossing in an extra pony is no big whoop and all the rest of the horsepower you use goes to directly shortening the time frame on a pretty even steven basis,

again not so with aerodynamics... You may indeed shorten your time frame, but you are going to pay dearly for it,,, this is why cars and trucks really eat it at high rates of speed...

so my point to all this is go ahead and pull that hill - get it over with, there will be inefficiencies in the engine itself running full bore as compared to half throttle and such but it's not a bad way to go as compared to bucking the wind... two totally different birds...

J Tiers
07-25-2014, 10:58 AM
another words, when it comes to air drag, want to go twice as fast? then it's going to cost you 4 times the horsepower and this is where in the name of economy things eat it REALLY REALLY bad --- for it does not matter if you get there twice as fast if your engine is sucking on a garden hose and using 4 times the amount of fuel whilst doing so,,,
..............
again not so with aerodynamics... You may indeed shorten your time frame, but you are going to pay dearly for it,,, this is why cars and trucks really eat it at high rates of speed...


Apparently there are some serious problems with the above. part is true, but does not support the rest.

It would be true IF the drag were to account for all the power used. But it does not, so drag increases do not directly multiply the fuel used.

If that were all true, then a 30 MPG vehicle would get 7.5 mpg at a higher speed where drag required 4x power. But that is obviously not what actually happens.

My 5 speed manual tranny S10 gets approximately 25 to 27 MPG at any speed from 50 to 75 mph. I have no data for higher speeds. There is no gross penalty for higher speeds such as the advocates for a 45 or 50 mph limit like to claim.

The REAL agenda of those folks is to make use of a car so onerous that people won't buy them. You can discount a lot of what they say, they mix truth with unsupported conclusions, basically telling lies that support their agenda.

The truth is that the drag is higher, but that it is not a large enough part of the fuel usage to make the sort of difference that those biased individuals like to claim.

A.K. Boomer
07-25-2014, 11:19 AM
If that were all true, then a 30 MPG vehicle would get 7.5 mpg at a higher speed where drag required 4x power. But that is obviously not what actually happens.



Again you missed an earlier point,,, even at 4 times the power being used your talking half the time frame, so your calculations are off - way off, the fuel line may indeed be transporting approximately 4 times the amount of goodies to the engine,,, BUT, it's only doing it for half the time, or covering twice as much ground,,, so it's not 7.5 MPG's - it's 15

But still piss poor, and again - the example with the hill is not, as long as the total speeds are fairly low and you don't have to start entering in aerodynamics the fuel for work exchange rate is much more "tit for tat"...

Edit; as far as your results with your S-10 and just bumping things up from 50 to 75 and there being no real detectible change I can believe that, you may be hitting a mechanical "sweet spot" in the way the truck was designed - gearing and how the engine is camm'ed and on and on, this happens all the time actually, does not really prove anything or disprove anything when you track the the real reasons as to why,,, and due to complicated shapes the "double the speed quadruple the force" rule is just a rough draft,,, at a slightly higher speed in a truck you may be getting that "rolling ball" or air in the back of the pick-up bed, where as if you slowed things down some it will start to turbulate.

what is a little more predictable is a vehicles frontal area, not perfect as there are still irregular shapes that create different situations depending on the speed but much more easy to predict throughout the range...

Willy
07-25-2014, 01:48 PM
.............
..........My 5 speed manual tranny S10 gets approximately 25 to 27 MPG at any speed from 50 to 75 mph. I have no data for higher speeds. There is no gross penalty for higher speeds such as the advocates for a 45 or 50 mph limit like to claim.

The REAL agenda of those folks is to make use of a car so onerous that people won't buy them. You can discount a lot of what they say, they mix truth with unsupported conclusions, basically telling lies that support their agenda.

The truth is that the drag is higher, but that it is not a large enough part of the fuel usage to make the sort of difference that those biased individuals like to claim.

Your joking right?
The easiest way to reduce drag and fuel consumption is to reduce speed.

Aerodynamic drag has a huge impact on fuel economy. Aircraft fly with the prevailing winds to reduce fuel consumption. They fly at high altitudes in order to reduce air density induced drag. Lately you'll also see wing-lets on the ends of fixed wing aircraft. These are either incorporated in newly designed aircraft or added on to older designs because they save fuel by reducing parasitic drag.


Every major truck manufacturer and carrier is scrambling to either use integrated aerodynamic drag reducing designs and technologies or add ons in order to reduce the largest cost of operation...fuel usage.
When fuel costs are $300-$600 a day per unit you do everything economicly feasable in order to lower your costs.
Aerodynamic drag increases substantially past 55-60 mph. Most major fleets have strict guidelines and penalties for drivers who consistently exceed 60 mph. The biggest factor influencing this stance is a reduction in fuel consumption. This can mean a savings of millions of dollars annually to a large fleet. Or the differnce of remaining viable for a small fleet.
Like the old saying goes...don't piss into the wind.:)

The picture and the link to a study below is already a little dated but have quick look at it anyway as it does underscore very well the importance of drag reduction.


Reducing Aerodynamic Drag and Fuel Consumption
Fred Browand
Aerospace and Mechanical Engineering
Viterbi School of Engineering
University of Southern California


(http://gcep.stanford.edu/pdfs/ChEHeXOTnf3dHH5qjYRXMA/10_Browand_10_11_trans.pdf)
http://i76.photobucket.com/albums/j31/250willy/AerodynamicDragvsFuelconsumption_zps8667391d.jpg

danlb
07-25-2014, 02:36 PM
So, the extra weight of a car with all sorts of safety features and creature comforts is not that big a hit, especially for a hybrid or EV.

For highway cruising, maybe. But I drive to work in stop-and-go.....

In the case of the hybrids, the impact of stop commute and go is MUCH less than in a normal car. Where my old car would get 12 MPG in stop and go traffic my hybrid gets 43 or so. Of course, it would probably be even better if the car were lighter. It takes more energy to accelerate a larger mass from a stop to 5 MPH than it does for a lighter mass.

I guess the real take-away is that your mileage while cruising down the level highway at a steady speed is barely impacted by weight. Air resistance and rolling losses are your enemy. When you are city driving it's the weight of your car and the weight of your foot that matter more.

Dan

Rich Carlstedt
07-25-2014, 04:56 PM
...............
why are new cars so heavy?
any thoughts?

Well, It has to do with the tires.
They put compressed air in them....
Compress anything and you get ? ...Heavy


Remember the old time cars with solid tires ?
Man, they were light ...but Detroit got carried away when they figured out that more weight is more traction...case solved !

By the way, that's what the Greenies are arguing about, compressing C02 makes the cars even heavier.
They want pure air so that mileage gets better...very simple !

Rich :)

Norman Bain
07-25-2014, 05:53 PM
I do like driving and think I do ok at it.

That said, I am firm in my mind I will be getting a self driven (driverless) car when they become practical.

Ries
07-25-2014, 06:42 PM
I live about five miles from Paccar's R&D facility- and almost every day, I see test mule semi's drive by. They spend millions every year trying to engineer an additional .25 mpg out of a new Kenworth or Peterbilt over there.
And a LOT of it is aerodynamic stuff.

CarlByrns
07-25-2014, 07:17 PM
I do like driving and think I do ok at it.

And therein lies a problem: everybody thinks they are an above-average driver :)

cameron
07-25-2014, 08:11 PM
And therein lies a problem: everybody thinks they are an above-average driver :)

And, of course, half of them are right.

J Tiers
07-25-2014, 10:08 PM
Your joking right?
The easiest way to reduce drag and fuel consumption is to reduce speed.


Not in the slightest. I assume YOU are.....

And AKB's 15 mpg is still so far wrong it is silly.

I get roughly the same mileage at 50 mph as at 75..... and this S10 is NOT the only vehicle to do that.

Take all those graphs and throw them away.... you are not using them correctly, and there is just no point....

If there was such a huge reduction in mileage, every car company in the world would long ago have been making cars that are aerodynamically good. BUT THEY DID NOT AND ARE NOT. Cars are "pretty good", but not designed to be extreme. And that is because the makers need styling, and they can AFFORD it, since the drag is not overwhelming everything else.

They use aerodynamics to shave small amounts of gas usage, not to make gross 2:1 savings.... not even 30% savings.... And they do it because they ahve to... they have to meet the requirements, and any tricks that get them a few tenths of an MPG more are all good.

The best aerodynamic design can ONLY affect the portion of the total engine load that is due to the air drag. Anything else is totally separate, and probably not affected by the shape of the car. Might be by weight, engine size, other parasitic loads inside the vehicle, etc.

Anyone can check out the "huge" reduction in gas mileage for themselves.... IF the power required is simply proportional to the speed ratio squared, WHICH I DENY, then 50 vs 75 is a ratio of 1.5, and the square is 2.25, so it should take 2.25x the power to go 75 mph meaning you burn gas at 2.25X the rate. You get there in 2/3 the time, and so you should use 1.5x the gas to do that.

If the vehicle gets 26 mpg at 50, then it should, according to the "reasoning", get cut to 26/1.5 = 17.33 mpg at 75 mpg. But, I certainly do not see that, and I suppose few if any people do. I continue to get 25 or so MPG at 75 mph.

The truth of the matter is that any particular shape of "projectile" has a somewhat different graph of drag vs speed. For some, it may be negligible until several hundred knots, that would be jet aircraft. For particularly bad shapes, it will begin to be important well within the automotive driving range of speeds.

For instance, a car progressing at 5 mph.... if you speed up to 10 mph, you do not burn gas at 4x the rate.... From 10 to 20 mph... again, not 4x the rate...... Obviously, there is a minimum speed below which the drag is simply not an issue. And that will depend on the shape of the vehicle.

Jet aircraft, which cannot even remain in the air at driving speeds, have in the past been fitted with "speed brakes"..... spoilers to increase drag, because they are so "clean" that they do not slow down well, even with power cut drastically. And that is a speeds many times faster than autos. It is their shape that allows them to go several hundred knots.

yes they burn more fuel, but the point is that their shape makes drag at driving speeds negligible. They must go much faster to get into significant drag.

ONLY if the drag becomes a significant portion of the total power needed at a particular speed, does the drastic savings occur from either slowing down, or improving the aerodynamic design.

It is wrong to assume that the wonderful graphs will necessarily give the effect on gas mileage shown for air drag alone.

The best thing to do is "know about it", and realize that there are a lot more details involved. Let the rabid tree-huggers squeal and squall about that stuff, looking ridicuous, you just start believing your actual gasoline bills.

Black_Moons
07-25-2014, 10:44 PM
Some fuel for the fire:
I get 110MPG riding at 37MPH on my motorized bicycle (Full throttle all the time, city traffic), bike is about 60lbs + 200lb rider. With next to 0 rolling friction, I can go up light inclines and still be doing 31MPH.
10MPH headwind? I'll be doing 29MPH. 10MPH tailwind? 45MPH.

If it was all about weight, a 1000lb car should get 25MPG and a 2000lb car would get 12.5MPG. But it seems 1000lb cars and 2000lb cars and even 4000lb cars all get 20~40MPG.

at 110MPG, most of my fuel is being spent on fighting drag. I am 18"~ wide and 4' tall on my bike (frontal area) Compare that to your 6' by 6' truck frontal area, also doing 40MPH.
Compare that and you might figure out 20~ MPG for most cars. Indeed many early cars/trucks are 20MPG.

Much more modern engines and designs are getting 30 or even 40MPG out of a similar weight car. Kinda pointing to the fact that my cheapo 2 stroke motor getting 110MPG is actually very inefficient, much like a 1900s car. Its just my drag is so much lower because I am smaller.

A.K. Boomer
07-26-2014, 12:35 AM
Not in the slightest. I assume YOU are.....

all due respect I would pick Willy over you to double check my math any day of the week, esp. since you already proven to yourself and everyone else that you are not only capable of missing huge links in your calculations but when brought to your attention keep on missing them and still continue to somehow have the audacity to "go on the offense"
It makes me wonder what the Cd is for being "thick as a brick"


And AKB's 15 mpg is still so far wrong it is silly.

again, my calculations are right on the money, it is you my friend who forgot the fact that twice the amount of ground was covered and therefore made the mistake and arrived at 7.5mpg,,,

rookie...


"If that were all true, then a 30 MPG vehicle would get 7.5 mpg at a higher speed where drag required 4x power. But that is obviously not what actually happens."


Again --- re-read post #62 and things will not be such a mystery to you,,, vehicle design and gearing and engine camming and on and on, and not by accident - wake up JT speed limit is not 55mph anymore, and while in most cases the drag increases drastically there is a mechanical efficiency factor that cannot be ignored, vehicle manufacturers realize this and try to design there vehicles so there mechanical "sweet spots" will fall into the range of where they will be driven...


plus the fact that pickup's create a perfect "roller bearing" of air in the back of the bed with the tailgate up at certain HIGHER speeds that actually cut drag down on that part of the truck, YES actually REDUCE it than if it was going slower and just creating turbulence ...


But don't listen to just me or Willy - take it from Nasa - watch the hillbilly video they put out about double the speed quadruple the force,,, it's really quite amusing - done up with a fish scale and a flat board on a stick in the back of a pick-up so you should be able to relate...

http://en.wikipedia.org/wiki/Drag_%28physics%29





For instance, a car progressing at 5 mph.... if you speed up to 10 mph, you do not burn gas at 4x the rate.... From 10 to 20 mph... again, not 4x the rate...... Obviously, there is a minimum speed below which the drag is simply not an issue. And that will depend on the shape of the vehicle.

yes now your starting to make sense , at that low of speed mechanical friction and accessories trump wind drag, look at Willy's truck chart - while not ideal it will give you an idea of how it works,,, 50mph is the speed at which mechanical drag is the same as air drag - and then things start taking over in the opposite direction and at an incredible rate, your truck probably varies some from this BECAUSE IT'S FRONTAL AREA IS NOT SHAPED LIKE A GARAGE DOOR --- so your match up between mechanical drag and accessories to the air drag might be 55mph or more...




It is wrong to assume that the wonderful graphs will necessarily give the effect on gas mileage shown for air drag alone.



Nobody here was stating that - that iv read anyways --- so many factors I don't have the time to go into it,,, but - at certain speeds where the air drag has taken over as the main HP consumer - rest assured if you start pushing it beyond you will have to come up with the extra goods to make it happen, and not just some extra goods - again and in general - double the speed --- quadruple the force... just a basic law of fluid dynamics... which also applies to aerodynamics...

J Tiers
07-26-2014, 01:32 AM
DAMN, dude...

Can anyone be so bloody insulting by accident.? What's the russian for "go face up in a hole and puke"? Consider it said.

You are also wrong.....

Nobody disputes that drag goes up with speed. the point is that it doesn't matter unless you get to the speed it DOES matter for your vehicle.

As for the rest of it, I got jumped for stating that I do not see the drastic change in fuel economy at higher speeds. I stand by that, and if "willy" is disputing that, he's wrong also. That "jumping" seems to indicate that numbers of people are expecting the drag equation to be dominant.... like any of the tree-hugging car haters who want to force folks to drive across country at 40 mph.... or not at all.

Other than that, we agree that IF you get above the critical speed, THEN it makes a big difference. That won't happen on the highway in any half-assed modern car, so your condescending crap is just so much puke when it comes to practical cars in a practical world, on real highways, at the real speeds people drive..

In THEORY, it CULD be a big deal... but in REALITY, it just gets buried in otehr losses, and has nowhere near the effect some are appearing to claim.

BTW... name a case of my being so far wrong on calcs, and prove how they are wrong.... I believe you will have a very hard time finding many, if any.

A.K. Boomer
07-26-2014, 02:26 AM
JT - at the speeds were talking somewhere in the middle lies the truth, again look at Willy's chart...

get away from those speeds and try to double them and your in for a big reality check,,,

don't like my attitude? change yours pilgrim,,,
You missed a major factor - I leveled the field at least double more accurate yet there is still all the mechanical frictional losses at lower speeds to content with - at higher its more about air and at that point - double that and it's almost all about air drag...

try a mileage run @ 120 mph in the S-10 and get back to me... have a nice day :)

The Artful Bodger
07-26-2014, 02:52 AM
Yeah, it is all about air drag, not so much at low speeds then increasing with a rush.

My ute uses less fuel towing a small trailer at 80-90 than it does without the trailer at 110.

Willy
07-26-2014, 06:19 AM
jt, no need debating this here with us, we didn't make up that silly graph or come up with those silly conclusions.
That's right, take it up with Fred Browand (http://ame-www.usc.edu/personnel/browand/), aerospace and mechanical engineering University of Southern California.


Education:

1965 Ph.D., Aeronautics and Astronautics Engineering, Massachusetts Institute of Technology
1960 M.S., Aeronautics and Astronautics Engineering, Massachusetts Institute of Technology
1960 B.S., Aeronautics and Astronautics Engineering, Massachusetts Institute of Technology
USC Academic Positions:

1981-: Professor, Department of Aerospace Engineering
1976-81: Associate Professor of Aerospace and Ocean Engineering, Department of Aerospace Engineering
1973-76: Senior Research Associate, Department of Aerospace Engineering
1967-73: Assistant Professor, Departments of Civil and Aerospace Engineering
Other Professional Positions:

1998: Visiting Professor, Graduate Aero Labs, California Institute of Technology
1991: Visiting Fellow: Wissenschaft Kolleg of Berlin
1991: Visiting Research Associate, Graduate Aero Labs, California Institute of Technology
1980-81: Research Associate, CNRS, University of Grenoble, Grenoble, France
1979: Visitor, Woods Hole Summer Program in Geophysical Fluid Dynamics
1966-67: Post Doctoral Fellow, Assistant Professor, Department of Aeronautics and Astronautics, MIT








But what does he know about the effects aerodynamic drag anyway other than that goofy study he did on it's effects on fuel consumption that I left the link to previously. I'm sure you didn't feel the need to read it after seeing his silly graph.

Better yet please notify all of the automobile and truck manufactures and tell them to stop this nonsense of needlessly spending billions of dollars on trying to reduce the coefficient of drag on vehicles. After all we are not going to drive them fast enough to have it make a difference.
You'll save them billions chasing this fallacy.

As for me, well I'm done with this. I'm going to be busy shopping for for an S-10 today. I've never heard of, never mind owned a vehicle that can do much more work, (well in my estimation at least) and yet use virtually the same amount of fuel in the process, all the while having the same coefficient of drag as that of a brick.
Hey I know this sounds like free energy but apparently it happens. Just think, I'll be able to drive at 75 mph and it won't cost me a cent more than when doing 50.
What's not to like?

A.K. Boomer
07-26-2014, 08:27 AM
While JT's mileage story does seem a little stretched there are funny things that can happen with certain vehicle design, heck even the guys that built and programmed his ECU could have a hefty hand in it with the unit falling into a certain lean spot at a certain load and demand,,, tons of factors and while it is a little tough to swallow that one could do as good at 70 as they do at 50 I also don't think JT's a liar,,, but his reasoning as to why it's happening is off that's all,,,

it is a pretty big deal at those speeds - it is the speed at which air drag has taken over as the major consumer of HP's

so anything above starts to get stacked on an ever increasing vertical graph...

as far as every car iv ever owned - they all seemed to consume more the more I pushed them --- just typical for me, but granted some worse than others,
My honda CRX's were amongst the best --- it did not matter as much, I accredit that to the cars being very slippery and the graph to where mechanical friction and air drag cross as equals was much higher to begin with,,,
so with a higher starting point not as much was noticed,,, the CRX's Cd was that of a modern hybrid, it also only took about 125 hp to push that car @ 135mph,,, I averaged 125mph going through kansas one time, my father was ill/dying and I had to get back to mich. I was not in the mode to keep track of mileage, I was peeing in coffee cups and tossing it out the window, I can tell you it was not my best tanks lol but I can also tell you I was going places.

my current vehicle - my honda del-sol is a drag queen,,, it has the same Cd as a crown vic -- and it is one of the worst for showing it, just from 60 to 70 I take a major hit in fuel economy, I would say I go from 35 to 30, that's terrible,
so I end up driving allot slower because of it... it's helped me cool my jets some and that's a good thing I guess...

the thing is is the front of this car looks pretty slippery, allot like the CRX except maybe not as much of a lower front air dam,,,

I guess it's the funky cut off at the top rear that's creating all the fuss,,, oh well it's still pretty good if I just keep the speed down,,, I have an extra 20 HP in the del sol V-tech and I can not even come close to touching the top speed of the old CRX, both cars I ram aired and have headers on and such, but the del sol is about 15 to 20 MPH off the mark of what the CRX could do... just flat out falls on its face... testimony to what it takes to go faster and the whole - double the speed quadruple the force factor... in my experience the shoe fits pretty accurately... and if there are discrepancies then there's logical reasoning behind it...

PStechPaul
07-26-2014, 09:59 AM
I'll show the formulae that I used in my EV calculator to demonstrate how it comes up with the force, power, and energy requirements:


fForce = (fMass*fGrav*fRoll) + ( ( (fAir*fDrag*fArea)*(fSpeed*fSpeed/12.96) ) / 2 ) + (fMass*fAccel);
fPower = fForce*fSpeed/3.6;

This may be a bit simplistic, but it bears out for many real-world cases. These are only the theoretical requirements to obtain or sustain the given speed, so the actual power needed and energy used will be greater.

One may estimate the drive-train efficiency as about 90%, and the fuel efficiency of an ICE at 25-30%. The calculator was designed for EVs, so the fuel efficiency is not taken into account at all.

For an EV, it is possible to consume zero power when not moving, and actually recoup energy (negative power) when going downhill or braking, while this is generally not the case for an ICE.

The torque, power, and efficiency curves for an electric motor are much different from those of an ICE, and are probably much more consistent and predictable.

For my own "real world" figures, my 5 speed all-manual Saturn averages about 30-35 MPG (better in the summer), and gets 40-46 MPG on long highway trips.

I usually don't do much more than 65 MPH, but I have a feeling that I get better fuel economy at 65 than 55, and it would probably drop somewhat at 75.

J Tiers
07-26-2014, 10:10 AM
Well, AK, you seem to have backed off a bit from your "Airsmith" mode.... that's all to the good.

Willy.... Chill out.... And try reading the posts.... it may help your understanding. Dr Broward's info is fine, IF YOU USE IT CORRECTLY. If you try to apply it where it does not apply in the slightest, well, garbage in, garbage out, you will go into the weeds.

That is why I suggested that Willy throw away the graphs.... he isn't using them right, and they will only confuse the issue.

OK.....

I seem to be getting 100% buy-in from AK here on the major point I made... he is NOW AGREEING that the shape of the vehicle makes a difference.... that the point where air drag overcomes mechanical issues is higher for some than for others. This is progress towards real understanding.

Willy, I am not so sure about..... he seems to think that a PHD's study applies to everything under every circumstance.... no matter how different from what was studied.

Dr Broward shows this very clearly in the first graph, but of course the point of it was missed.... THAT WAS FOR 18 WHEEL TRUCKS.

Willy apparently thinks those are the very same thing as a sedan that has been somewhat optimized for airflow.... or even a small truck with a cap. Maybe on some other planet, but definitely not here on earth.

The standard 18 wheel truck, even with some streamlining of the cab, is an aerodynamic PIG.... wheels, undercarriage, big flat back, in many cases no air shield over the cab, big gap between shield and trailer box... they purely SUCK, and yet, even they have a turn-over point in the 50 mph area.... where drag and friction are equal. This is all brought out in the paper, if you will only READ it, and not jump to conclusions.

Read further in the study and notice the multi-vehicle tests. Two vehicles, close enough to form a semi-single vehicle that is longer, have a total drag that is less than they have in isolation, summed up. In some cases the drag is so much less that the net for BOTH is nearly at or below the drag for ONE.. the two van shaped vehicles show 0.6 and 0.7 x the drag when not in tandem, if the separation is zero. If there were no gap due to the sloped front of the "van shape", the net ratio might be closer to 0.5, and the combination might actually reach the same drag as one alone. I'd like to see results on the effect of filling in that gap.

That likely explains the S10.... it is a LONG vehicle, since it is an extended cab, with a close0fitting cap and very little gap between the cap and cab. The cap itself has some slope on the rear, and is not a square box. It is a 2000, so it has a lot more streamlining on the nose than older S10 types have.

The net is probably enough to move the crossover point up. I would certainly expect the crossover to be better than an 18 wheel truck.... even given the much lower friction. But of course I cannot prove that, other than observing that the fuel economy is not adversely affected by the speed ranges mentioned.

A run a 110mph? I doubt it could GET TO 110 mph. it has a 4:10 rear end..... and a 2.2l flex fuel engine. But at 110 mph I would not be the slightest bit surprised to find a much more significant drag effect. I just don't see it at 75 mph....

Now.... If you look at the effect of running at 1/2 the turn-over point, vs AT the turn-over point.....

At turn-over, the total drag equals friction. At half speed, drag is 4x less. But, using Dr Broward's graph, friction is 1/2 as well....(plus a base line) so drag is more like half of friction at the lower speed, not 1/4. That tends to dilute the effect, BUT it also implies the ability to get better mileage by running slower than even highway speeds. It implies a proportionality that experience suggests is not present, although I admit I have not run a full tank out at 35 mph and then another at 50 mph, under same conditions. The old "Mobil economy run" may give some data about that, assuming it still applies to modern cars.

And teh baseline friction probably makes the effect of lower speed less marked. THAT is going to be very dependent on the exact vehicle, oil type, tire type and inflation, etc.

If you are AT the turnover point, then drag is half the total. AND ITS EFFECT IS HALF OF THE TOTAL... in other words, if you ELIMINATED drag at that point, you would take away ONLY HALF the total power needed.... reducing drag by half would only improve fuel usage per unit time by 1/4.

That significantly dilutes the supposedly huge effect of drag. You need to be at a point where drag is DOMINANT to get the real square law effect.

I am not sure this proportional friction idea applies universally, either, although it must apply to 18 wheel trucks per the study data. It assumes some things about friction, such as that it provides a constant force opposing motion. If friction were a constant force, then moving half as far per unit time would equal half the power expended. However, on-road fuel consumption does not really seem to follow that. There are many more factors.

In any case, the argument about fuel per unit time vs units of time used to make the trip come into play. if you want to predict liters per km, or miles per gallon, you need to always look at the data in those terms.... it gets confusing to quote off some things one way, and try to compare them to others in different units, like fuel per unit time, etc.

As for teh friction, I suspect that some of the friction is reasonably constant in proportion to speed, and some is non-linearly speed dependent. Some is viscous, some is due to tire deflection, etc. At speed, centripetal force may affect tire deflection, for instance, since it acts in the same direction as tire pressure.

And, there is a base constant fuel usage for engine 'stuff", some of which is again linear, and some may be non-linear. Engine efficiency is also a factor.... some fuel is used if you go at ZERO speed, and that gets added in as well, further confusing the issue.

It is very difficult to do the predictions unless you stick with the goal, which is miles per gallon/liters per km.

vpt
07-26-2014, 10:10 AM
My 4 ton+ diesel excursion gets 20mpg+.

Seastar
07-26-2014, 10:46 AM
OMG! OMG!
My head is about to explode!
I long for the good old days when all we talked about was top speed, 0 to 60 times and how fast you could do the 1/4 mile.
BTW I drive a 2014 Jeep SRT and love it.
Bill

PS: I hear ford will have an all AL F150 next year.

danlb
07-26-2014, 11:46 AM
I'm not trying to start a fight, but it seems that it's really easy to claim any mileage that you want on any car. It's usually a matter of one of these;

a) Remembering the outstanding mileage that you got one time.
b) Using the mileage from that stretch of road that has a very slight downgrade
c) Using the roads where you get on and drive for hours without ever encountering a hill or any other reason to slow down.
d) Over filling the tank once and underfilling it the next, which effectively adds a gallon or two to the equation.
e) Not doing any measuring at all and just guessing.
f) Measure when going one direction but not the other (negates slopes)

Many of the recent models have instrumentation that will will give you real time mileage information. On my particular model, I'd get MORE THAN than 65 MPG if I could drive from San Francisco to LA at a constant 43 MPH with no stops or reason to speed up.. That's the sweet point where everything is running at it's most optimal and the wind resistance is balanced against driving time. Of course, there is no road where I can safely do that.

I've seen the results of extra speed directly. I drove the same route every day for weeks. It was about 90 miles and I drove outside of commute at 55. IT took exactly 1/4 tank of gas round trip, day after day. One day I overslept. It was extremely important that I was not late. I had a bit more than 1/3 tank of gas when I jumped in the car and blasted down the freeway at 80 MPH. And ran out of gas. That extra 50% speed did me in.

... and an old joke, updated: The neighbor on my left has a new Chevy volt. He brags that he gets over 50 MPG and the first 50 miles are free because they are electric. While chatting with my other neighbor, we discussed the miraculous mileage of his car. "How can I get mileage as good as his?" I asked. "Simple", came the reply. "Do the same he does. Lie about it."


Dan

PStechPaul
07-26-2014, 12:12 PM
A couple of jokes:

1. The highway patrolman pulled over a pretty blonde who was speeding down the road. When asked why, she said, "Officer, I was almost out of gas, and I had to hurry to the gas station before it ran out!"

2. A true story (I think). There was a guy where my father worked who had bought a new VW bug (when they were still uncommon), and he was bragging about how he was getting, like, 30 MPG while everyone else was getting about 20 in their big 60s gas gulpers. So a couple of the guys conspired to put extra gas in his tank (no gas cap locks those days), and after a while he bragged even louder that he was now getting 40 MPG, and then even an unbelievable 50! But then they pulled the reverse trick, siphoning some out every day, and then he became rather quiet, and I think he even got so discouraged he sold the car!

BTW, I keep records on the fuel consumption and mileage on my vehicles, although I've been somewhat remiss lately. But here is the chart showing the MPG and $/gal since I purchased it in 2008:

http://enginuitysystems.com/pix/GasMileage_Saturn99.jpg

MPG - Blue, $/gal -Magenta

A.K. Boomer
07-26-2014, 01:14 PM
I seem to be getting 100% buy-in from AK here on the major point I made... he is NOW AGREEING that the shape of the vehicle makes a difference.... that the point where air drag overcomes mechanical issues is higher for some than for others. This is progress towards real understanding.

.


STOP ---------- stop it! this is why you catch so much dang flack,,, you don't make sense and you also try to constantly and unfairly twist things around...

this is what I wrote BACK ON POST #72 It's what Iv been saying all along...

look at Willy's truck chart - while not ideal it will give you an idea of how it works,,, 50mph is the speed at which mechanical drag is the same as air drag - and then things start taking over in the opposite direction and at an incredible rate, your truck probably varies some from this BECAUSE IT'S FRONTAL AREA IS NOT SHAPED LIKE A GARAGE DOOR --- so your match up between mechanical drag and accessories to the air drag might be 55mph or more...


Stop freaking out dude, Gain control of your situation and stay there...


PStech where the hell did you get gas for a buck and a half in 2008?

A.K. Boomer
07-26-2014, 01:28 PM
Paul, at second glance your chart fascinates me...


there is an incredible relationship between the price paid for a gallon of fuel and the MPG's

and barring cheaper ethanol fuel stations that do indeed sell for a lower rate the graph shows substantial fluctuations and in fact too much so - it's beyond ethanol - even though it is cheaper and yes you take a hit in MPG's, but not that much with only about 10 to 15% added...

I think the chart shows what I would expect to see if I had a graph of the same nature,,,

you adjust your driving habits depending on how much you had to pay at the pump - and not by a small margin --- your in tune pretty good that way...

you get stung at the pump and you baby that tankful.

PStechPaul
07-26-2014, 01:31 PM
It was at Hughes Oceanic in Lutherville:



Date
Description
Odometer
Miles
Gallons
Price
Total
MPG





11/24/08
Hughes Oceanic Luth
67497
325.8
10.117
$1.819
$18.40
32.20


12/01/08
Hughes Oceanic Luth
67813
316.2
10.475
$1.539
$16.12
30.19


01/26/09
JiffyMart Finksburg
68106
292.2
10.454
$1.719
$17.97
27.95



Funny that my fuel consumption hit an all-time low at the same time as the price? Maybe it was E85? Corn squeezin's? An evil right-wing plot to crash the economy right after Obama's election? (Oops, it already had crashed!) Change we can believe in? I got change back from a twenty for a full tank - don't see that much anymore... :p

RichR
07-26-2014, 01:47 PM
I once graphed the fuel mileage I got for my car and the graph was very similar to Pauls. The fluctuations you see are seasonal, with mileage dropping off
in the colder weather and improving when it gets warmer.

mattthemuppet
07-26-2014, 02:02 PM
Blimey, this is like one of those old iron vs chicom arguments!

Another anecdote, purely backed up by days of driving and subject to the fallacies of memory - while we were driving across country I kept an eye on the mileage at each stop cos I'm anal like that. When we were doing around 65 we were getting around 28mpg, going up to 75 ( which my 14 year old overloaded focus did not like at all) brought it down to around 25 and titling through Yellowstone at 45mph brought it up to about 33mpg. Load was around the same ( distance should cancel out the effect of bowl evacuations) and it was all pretty much constant speed. With me on the car alone at 60 or so it gets around 30mpg.

The drop in fuel economy with higher speed was noticeable enough for me to not bother trying to do the speed limit through Montana, even if the car could do it (doubtful). Saw a lot of trucks with side skirts and those funky trail feather things too

A.K. Boomer
07-26-2014, 02:03 PM
That's a good point Rich but why would that drag the price along with it?

it's not perfect but on the average follows (or should I say leads) the MPG's esp. some of the huge spikes...

SteveF
07-26-2014, 03:12 PM
..............
I get roughly the same mileage at 50 mph as at 75..... and this S10 is NOT the only vehicle to do that.
...................

Too bad you couldn't get CR to include it in their tests.

http://www.consumerreports.org/cro/news/2009/09/tested-speed-vs-fuel-economy/index.htm

Steve

RichR
07-26-2014, 05:07 PM
That's a good point Rich but why would that drag the price along with it?

it's not perfect but on the average follows (or should I say leads) the MPG's esp. some of the huge spikes...

Supply and demand? Summer vacationers driving to their destinations?

J Tiers
07-26-2014, 06:06 PM
In case there is any question... I drive the same long trips every year.....(visit same relatives) and I keep a log of gas consumption, etc, for each vehicle. Gallons purchased, and miles driven are logged, along with other data, for all the vehicles, all the time. It's very very difficult to quarrel with mileage on a trip that is consistently the same distance at the same time of year, on the same roads, and takes multiple tanks, so that gas is bought at least once during any leg of the trip.....

It's also hard to argue for poor record keeping when the vehicle consistently goes to the same place, +- a few miles, on a full tank, before needing filled.

The S10 has been very consistent, drivings slower, or driving faster. Some years there is so much construction that we have a large part of the trip at 50 or 55 mph, but there is no particular difference in fuel usage or end-of-tank point. Some times I just drive slower for one or another reason. Some years we leave late, and I "lead-foot" it, but it doesn't make a big difference.

AK, who is getting a little *dramatic* with his "stop freaking out" routines, may, or may not, be still arguing for the drop to 17 mpg.... but if that were teh case, I should see a 25% drop in mileage, and a need to buy gas far sooner, However, I do not see any such thing.

Dry tank range at 25mpg ought to be 475m, but only 323 at 17mpg, which is well into the noticeable difference area.... I'd for sure know about that.

There are definite "outliers", like the car years ago that usually got 27mpg, but got 33 one time on "kokolene" bought in Indiana.... It wasn't ethanol gas, but "pure gas", so it is understandable. And teh fact that the records "caught" that outlier tends to validate them, actually.

You have to remember, it is not all friction and drag. There is acceleration, which is not so much of the time, but there is also going up hills, often long grades. Yes, you get a benefit on the way down, but that doesn't affect your "baseline" fuel consumption, the zero speed consumption.

Every highway outside of Kansas etc has hills, and each one requires the energy to lift the vehicle to the top from the flat, but you do not necessarily get it back... it is not a "reversible" operation. It could only be partly reversible if you coasted down after reaching the peak, not holding down your speed, but just letting it rip.

You might be surprised how much acceleration and deceleration you do even when you THINK you are holding speed. It's one reason for cruise control, but even that "races" up hills at teh set speed, instead of allowing a slow-down. Back with carbs, you could do well holding a constant manifold pressure.

It all adds up.

A.K. Boomer
07-26-2014, 07:24 PM
JT your 2000 S-10 has the same Cd rating as a volkswagon vanagon, not exactly what you would call "slippery":p

go into dimensions and capacity's and expand; http://www.carsdirect.com/compare/compare-tool?acodes=USB00CHT163B0

so solly,,, no silver bullet there pal --- you better start looking for answers elsewhere,,, Your not "special" (well actually not true, you are special) your not "immune to the laws of physics" you haven't found some kind of secret loophole,,,

now, I have given you many possibilities as to the hows and whys --- it would be a great thing if you want to add to the mix, but if not then at the very least stop yappin yer gums and try to read what i wrote and learn "why"

don't keep burying your head in the sand saying "can't be true --- not how my truck works"

you just maybe standing in your garage a week from now with one of your precious S-10 pistons in your hand that has a melted hole in it finding out just how it really works,,,

for the most part I like your "devils advocate" type nature,,, but when persistent in the face of reason it starts to get a little old ---- Now ------------ just to clarify --- nobody's "out to get you" and there's no huge conspiracy theory's on drag coefficients and how "the gubbermint won't tell you the truth"

it's all out there to grab and get a hold of my friend - and stuff it in your brain and maybe it will stick... good luck on your new journey for the truth...

Rich Carlstedt
07-26-2014, 07:42 PM
I see no sense in showing mileage comparisons without recognizing the change in fuels.
I get 2 MPG more in my F 150 PU when I use gas without ethanol versus "Up to 10 % Ethanol " fuel

I can see the difference and feel it

Rich

justanengineer
07-26-2014, 07:57 PM
My 5 speed manual tranny S10 gets approximately 25 to 27 MPG at any speed from 50 to 75 mph. I have no data for higher speeds. There is no gross penalty for higher speeds such as the advocates for a 45 or 50 mph limit like to claim.



In case there is any question... I drive the same long trips every year.....(visit same relatives) and I keep a log of gas consumption, etc, for each vehicle. Gallons purchased, and miles driven are logged, along with other data, for all the vehicles, all the time. It's very very difficult to quarrel with mileage on a trip that is consistently the same distance at the same time of year, on the same roads, and takes multiple tanks, so that gas is bought at least once during any leg of the trip.....


JT, my '99 does the exact same thing but is a bit better on mileage, ~32 pretty much regardless of the speed. Vehicle dynamics are just that, dynamic and change greatly over the entire speed range. In my truck for example, <30 mph I bounce quite a bit with the bumps, >30 mph and I "float" over the same bumps/potholes. Cant say Ive noticed an effect in the truck, but my Firebird's suspension is hugely influenced by speed. It shifts into high gear 70-75 mph, then it starts to seriously squat down and the handling improves with speed, below 70 I have issues with the rear of it "skipping" sideways around curves bc of a lack of downforce.

A.K. Boomer
07-26-2014, 10:43 PM
Ok - this is just for the record, JAE, are you making the statement that you get 32 MPG in your stock S-10 pick-up @ 75mph or More?

Old Hat
07-26-2014, 11:10 PM
Quit weighing your rides in metric and try our system.
It's less for sure!
Nothing you own will weigh in at more the '3' (three)

Less than 3 tons, sounds lighter allready.:o

J Tiers
07-27-2014, 12:49 AM
Rich... my data DETECTED fuel differences.... which seems to validate it.... All the S10 data is with modern ethanol mixes of 10%


JT your 2000 S-10 has the same Cd rating as a volkswagon vanagon, not exactly what you would call "slippery":p



AK, you need to learn to READ.... and write less condescending "new journey to the truth" bull crap.

Did you forget a few little detail things? Such as the fact that this vehicle has a CAP ON IT? That significantly modifies the aerodynamics by lengthening the full cross-section portion of the vehicle, AND eliminating the large flat behind the cab..... It also adds some tapered tail effect. In fact, it does to the S10 many of the things recommended for 18 wheel trucks in the report from the professor that was linked earlier.

It has been shown in other discussions right on this forum, back when Evan was still actively contributing, that an optimum cap shape was very beneficial.

I would not claim that this cap is shaped exactly like that optimized one that was in a report linked to back then (with test data), but it is intermediate, and certainly produces a shape very different from a "vanagon", which is basically a relatively short big box on wheels.

The unaltered S10 may have a less good drag coefficient, but that is not the same vehicle as it is with a cap on it. So the data for that are invalid, they are for a different and untested configuration.

In any case, you have what might be called "wikipedia info", and stats on a rather different configuration of vehicle from mine. I have long-term data for thousands of highway miles, on various roads with different speed limits, relating to this particular vehicle. My data shows an effect *somewhat different from* your "wikipedia" type links.... (OK "wikipedia" is mean, and you haven't cited it, but that doesn't mean I won't call it that... it is general data that doesn't apply directly)

At least Willy's link was to measured data by a respected researcher. And, Willy's link shows some reasons why I SHOULD see what I do see.

I don't know what you are getting at with whatever you said about pistons.... but they have gone 160,000 miles so far, and don't owe me a thing. I suppose you are making some comment about lean mixtures, overheating and knocking, etc... but ....

Basically I have 160,000 miles of road data..... All the sputtering and stammering in the world isn't as good as test data. It is up to YOU to give a cogent reason why you think the data is what it is.

If you think the data is wrong, you need to explain why it is wrong, aside from stammering that it "can't be right because these other sites don't show it".

As for the vanagon..... it's shorter..... wheelbase 96 inch, vs 123 inch, 179" overall vs 204", so the S10 has the advantage on the length improvement.

The S10 is not as wide (68 vs 72 inches) and is well shorter (63 vs 75 inches), so it's cross-section is less. The length to cross-section form factor is different.

With the cap on it, the S10 is generally a longer, but slimmer shape, totally lacking the big blunt front, and sharp squared-off back of the vanagon. No relation the the bare truck with the cab that sticks up like a bobtail semi....

You simply cannot use the drag coefficient from the no-cap truck for the truck with cap. It's a different unit.... Saying it's the same unit is much like disregarding the improvements that professor in willy's link suggested..... saying "ah, those won't do no good"..... When the prof has the data to back them up.

Maybe *you* need some sort of your own "journey toward truth".........

Old Hat
07-27-2014, 01:16 AM
Tiers!
You been swimming in cold water?
Your sig has shrunk down to nearly nothing!;)

big job
07-27-2014, 07:46 AM
Then I should get the heavy award. 5900lbs dry weight 1959 Lincoln MK 4 Continental. I owned it since 1961. We have
gas records from back then allmost 19 1/2 mpg= now with this junk gas its down to 15 16 mpg probably cause I have to
run it retarded (its 10:5) compression made for 100 leaded octane. I cant even keep gas in a lawnmower no more.
sam

A.K. Boomer
07-27-2014, 08:31 AM
Well that's one magic cap JT, don't sell it or anything, don't change a thing, it's strange because I have many customers with all kinds of caps and they never talk about such gains, and im aware of what they get efficiency wise because it's always brought up...

Now you really have me curious about justanengineers claim of 32mpg regardless of speeds,,, Does he have one of these magical caps?


caps help some - but they also hurt some too,,, there's just a little more help than hurt that's all - they by no means effect the PRIMARY DRAG of a vehicle which means you are stuck with the same old bulky front end which incidentally is responsible for the majority of the "lame" .44 drag coefficient rating...

yes youv cleaned up the secondary air some, the behind the cab drag and pick-ups bed, but you don't get off "scott free"

you now have created a higher "blunt stopped" profile in the rear and are dragging air along with you in turbulence behind... just how it works,,, now if you kept it going after that and shaped it like a turd you may have something called an "aerodynamic longtail"

But you don't - don't confuse your truck with anything that would be considered "slippery"

its still a wind pig... good day.

A.K. Boomer
07-27-2014, 08:43 AM
Ladies and Gentleman I stand corrected,,,

picture of JT's "magic cap" that defies the laws of fluid dynamics... the faster you go the more the "turd taper" will push you...

it's one of those slap your forehead while saying "why didn't I think of that"

http://i146.photobucket.com/albums/r249/AK_Boomer/Misc.jpg (http://s146.photobucket.com/user/AK_Boomer/media/Misc.jpg.html)

seriously JT, even if your vehicle does look like the pic above, it still has to pay the same old price with the POS front end that everyone else does and is still subject to all the laws of aerodynamics that apply including double the speed quadruple the force,,, again, good day...

J Tiers
07-27-2014, 09:17 AM
AK....

Since you are just getting ridiculous here, I am basically DONE WITH YOU......

But. the cap is not a flat back, it is somewhat sloped, which you would know if you actually read the posts, instead of skimming a couple sentences and jumping to conclusions.

Your arguments seem to be that a brick and a trout are just the same thing as far as flow is concerned. You seem to believe that shape has no effect on the drag coefficient. And as soon as anyone suggests they may be different, you go into that mode of "kindly suggesting some study and learning"..... or trying to throw scorn on the "magic cap" etc..... Instead of reading the post, doing some learning of your own, and increasing your understanding.


Lesseee.... "a" is a rectangular block.... "b" is smaller, longer, and more streamlined...... NAH, they are just the same thing..... makes no difference.

It does not seem as if you even read the link from Willy.... or you would not keep saying that the total force on the vehicle quadruples from a doubling of speed. The graphs would have shown you your error...... too bad you didn't look at them.

So please do have a nice day..... but I am sure you will, it seems to be always sunny and happy where you are.... even if it's raining.

A.K. Boomer
07-27-2014, 09:51 AM
JT, it's just a rough draft but separate the mechanical/frictional forces from the air drag,

then go back and look at Willy's graph again and just look at the air drag chart and compare it to what it takes HP wise --- that's what im talking about, it's actually stacked greatly in the favor of "double the speed quadruple the force"

and when it takes over as the main drag contributor in ANY vehicle then to go beyond simply starts to take allot more energies, done deal can't be argued... one of those "is what it is" things...

Now, Still waiting to hear from just an engineer about if he has one of your magic caps or not --- what do you think of 32mpg out of a pickup regardless of speed? would really like to get your opinion on that...

I don't call people liars because I always give them the bennie of the doubt mostly due to mistakes not intentional,

but besides all the information I gave you about possibilities on the hows and whys that you seem to refuse to acknowledge (don't mind me JT, just been at it for over 40 years here bro),,, back on post #82 Danlb put together some things together that may help you diagnose your situation also,,,
and I know it will help justanengineer due to what he claims being unexplainable unless some kind of error was made...

so anyways for what it's worth please do go through Danlb's checklist for if it's not some of my suggestions or similar then it most likely lies here;

"I'm not trying to start a fight, but it seems that it's really easy to claim any mileage that you want on any car. It's usually a matter of one of these;

a) Remembering the outstanding mileage that you got one time.
b) Using the mileage from that stretch of road that has a very slight downgrade
c) Using the roads where you get on and drive for hours without ever encountering a hill or any other reason to slow down.
d) Over filling the tank once and underfilling it the next, which effectively adds a gallon or two to the equation.
e) Not doing any measuring at all and just guessing.
f) Measure when going one direction but not the other (negates slopes)"

justanengineer
07-27-2014, 10:28 AM
Ok - this is just for the record, JAE, are you making the statement that you get 32 MPG in your stock S-10 pick-up @ 75mph or More?

I'm saying that I get ~32 under normal driving situations, which for me is ~50 locally and ~70-75 on longer trips, but my truck hasnt had a stock ECM tune since new. Thinking about it last night I am surprised I missed the obvious, if JT's truck is geared like mine with the 2.73 (IIRC) rear its only turning ~3k RPM at 75 (IIRC, mine's ~2800) which from my vague memory of some charts I made 15 years ago should be well below peak efficiency (~4k IIRC). I suspect there is an offset between engine efficiency and aero losses. Above 75 mph I dont believe I ever had enough data to make any claims, even at 3k RPM these engines are screaming and my truck is a daily toy for hauling (hopefully today a 50s jukebox!), not for acting like a fool. I have had it maxed out at 94 several times for short bursts when it was still new so I know it can do it, but that was ~15 years ago now.

A.K. Boomer
07-27-2014, 10:41 AM
Well that makes much more sense - still high MPG to begin with but It's an easier pill to swallow with around town driving and high highways speeds equalizing.

your also on the right track as far as gearing - it's one of the things I mentioned to JT long ago in this post,,, gearing, cam timing, and perhaps the ECU falling into a nice little sweet spot with all the sensors are where it's at.

You have the realization that it indeed takes a fair amount of power for JT to go from 50 to 75mph in the form of air drag and are looking for answers elsewhere, that's where it's at, JT seems to be stuck in thinking that there's no real extra penalty to pay... he's dead wrong. it's just that his truck is compensating in other area's for it...

last question to you JAE -- are you running a topper?

A.K. Boomer
07-27-2014, 11:58 AM
AK....


Your arguments seem to be that a brick and a trout are just the same thing as far as flow is concerned. You seem to believe that shape has no effect on the drag coefficient. And as soon as anyone suggests they may be different, you go into that mode of "kindly suggesting some study and learning"..... or trying to throw scorn on the "magic cap" etc..... Instead of reading the post, doing some learning of your own, and increasing your understanding.





And once again YOUR NOT LISTENING -------- what Im saying is no matter if you have a brick IN THE BACK or a trout it's irrelevant because you still have a brick UP FRONT and that's the MAJORITY of your air drag,

unless your driving a brick in the back @ 50mph and then switching over to the trout ass end when going 75 your screwed --- your not doing that are you?

once again -- your not immune to the laws of fluid dynamics... deal with it, there's changes elsewhere that are making no change in fuel consumption, period... it's taking more energies but many things have changed with the trucks gearing and RPM range and on and on,,, your forgetting about the efficiency change that the engine is going through...

there is NO FREE LUNCH, YOU HAVE MORE DRAG, SO YOUR ENGINE IS RUNNING MORE EFFICIENT AT 70 than 50 ------------------------------------------ GET IT?


Or - you've missed something when calculating your mileage... end of discussion...

Glug
07-27-2014, 12:09 PM
Fwiw, it is fairly easy to measure the "pulse width" of the signal that actuates the fuel injectors. That will give a very accurate instantaneous measure of fuel consumption on fuel injected vehicles, or total consumption over time.

A project called the MPGUINO does just that, using an arduino and just a few electronic bits. It also measures the speed of the vehicle, giving MPG. This is a great way to determine efficiency at various cruising speeds.

http://ecomodder.com/wiki/index.php/MPGuino

Glug
07-27-2014, 12:14 PM
Btw, on the original topic-

In the 90's I worked on the r&d campus at one of the big three. We were all invited to stop by the weight reduction engineering center to review designs for possible improvement. That consisted of an entire vehicle spread out on many tables in a large room. Each part was tagged and you could write your suggestions for reducing the weight of the part on the tag. The aluminum suppliers liked to write "make out of aluminum" on all the tags.

Another room was full of car doors from many different manufacturers. Porsche 928 doors are heavy.

So they were very very serious about weight reduction, even way back then.

J Tiers
07-27-2014, 12:42 PM
Glug.....

Most of those fuel usage indicators, at least the ones built into some vehicles, are not as accurate as they could be. I have seen cars with them (belong to folks I know) which if you believe the computer, the thing is "over unity" driving with air as fuel.....

But it's very difficult to argue with "X" fuel in and "Y" miles driven. That's actual data, averaging over many hundreds of thousands of fuel pulses. And the gas pumps are pretty accurate.... the state inspectors make sure of that. I'll go with the log over the calculation any day, although the calculation by the car computer is bound to be pretty good as a short term RELATIVE indicator at any given time.

On the original subject.... The very fact that weight reduction is considered important is a strong clue.... It's too bad that AK (and others) is so fixated on that "if you drive faster you WILL BURN MORE FUEL ACCORDING TO THIS EXACT DRAG FORMULA" idea.... If he paid attention to all the other things that manufacturers do to get better mileage, he might actually learn something.

For that matter, if they looked at Willy's graph they might notice that the friction is the main loss up to a certain speed, which is about 50 mph for an 18 wheeler... probably a lot better for any somewhat streamlined vehicle.... But then, they think all vehicles are the same shape as a Volkswagen van.....

A light weight car, with high pressure tires and decent streamlining, is bound to get better mileage, assuming it does not waste fuel on non-essentials like A/C, entertainment, etc, etc. But so far that isn't what is being built, it's seemingly huge SUVs that get built (and bought), heavy things with the aerodynamics of a square block.

Many cars USED TO GET much better mileage..... 1960s VW bugs easily got 35 mpg.... so did early import Japanese pickup trucks.... which were not particularly aerodynamic....

over the last maybe 20 years, until recently, that was considered exotic good mileage...that could only be had with tiny 3 cylinder vehicles... only now are mainstream vehicles getting there again

A.K. Boomer
07-27-2014, 01:41 PM
. It's too bad that AK is so fixated on that "if you drive faster you WILL BURN MORE FUEL ACCORDING TO THIS EXACT DRAG FORMULA" idea.... If he paid attention to all the other things that manufacturers do to get better mileage, he might actually learn something.


hello, Never ever stated that,,, what I stated was that if you drive faster you will create more drag and have to use more Horsepower to get over it,,, and incidentally im the one that brought it up to you about manufacturers being aware of this and designing their drivetrains to fall into a certain "sweet spot" for improved efficiencies at certain speeds...


For that matter, if he looked at Willy's graph he might notice that the friction is the main loss up to a certain speed, which is about 50 mph for an 18 wheeler... probably a lot better for any somewhat streamlined vehicle.... But then, he thinks all vehicles are the same shape as a Volkswagen van.....

JT, cars are not that far off from the big rigs -- about 5mph increase to where the break even spot is --- everybody pays the price after a certain speed including you but i'll explain how and why,

well no actually I won't i'll let someone else do it because you don't seem to listen to what I say so I will let someone else tell you what iv been saying all along;

How much?

According to studies backed by the department of energy, the average car will be at its advertised MPG at 55 mph. But as the speed increases:

- 3% less efficient at 60 mph
- 8% less efficient at 65 mph
- 17% less efficient at 70 mph
- 23% less efficient at 75 mph
- 28% less efficient at 80 mph


Why?

This effect happens for two reasons:

1) "Pushing air around actually takes up about 40% of a car's energy at highway speeds. Traveling faster makes the job even harder...The increase is actually exponential, meaning wind resistance rises much more steeply between 70 and 80 mph than it does between 50 and 60. "

2) Engines are designed for specific speed, temperature, and rpm ranges. Driving out of these ranges goes against the fundamental design of the engine.


http://www.mpgforspeed.com/


now --- about the price you pay,,, if your vehicle gets the same mileage at 70 that it does at 50 then guess what? chevy is robbing peter to pay paul, anotherwords your truck could be doing so much better down low, you would probably be in the low 30's --- but hey - if you spend the majority of your time well above 55mph its a wise choice, just telling you how stuff actually works...

Your not "cheating the wind" in any way shape or form from 50 to 75, you can cheat it for both - but it will still be far more at 75 than it is for 50 no matter what shape you make that turd...

A.K. Boomer
07-27-2014, 02:32 PM
more; different shapes and sizes don't really matter all that much


Which cars?

Regardless of your vehicle, engine, or size, the numbers hold true. Green Car Congress did a study comparing different car model against this topic.

http://www.mpgforspeed.com/different_cars.png

and im sure the prius is way more slipperier than your truck ,, any questions?



and you were talking jets?


Other applications

This principle not only applies to cars, but other vehicles as well. Recently airlines have been slowing down their planes in an effort to ease fuel consumption. Most flights are being decreased by 10 mph, adding an average of 2-3 minutes more travel time in most cases.

The effect?
- Southwest Airlines will save $42 million in fuel costs per year.
- JetBlue will save $13.6 million per year
- United will save $20 million per year

danlb
07-27-2014, 05:14 PM
Glug.....

For that matter, if they looked at Willy's graph they might notice that the friction is the main loss up to a certain speed, which is about 50 mph for an 18 wheeler... probably a lot better for any somewhat streamlined vehicle.... But then, they think all vehicles are the same shape as a Volkswagen van.....



At first I thought you had it wrong, then realized that if you had a moderately decent cd (coefficient of drag) and high friction losses you do end up with a vehicle that breaks even at a higher speed. The parsing of the phrase "probably a lot better for any somewhat streamlined vehicle" could be taken many ways.

One of the neat things about trucks (18 wheelers) is that they have a decent cd for such a large vehicle. The frontal area is fairly small when compared to the cubic feet. The number of pounds of cargo per gallon of fuel per mile is pretty impressive.

What is really ideal is a low cd (like the Prius) AND low RR (rolling resistance). If I recall correctly, my model of the Prius uses more energy to overcome the air resistance starting at about 38 MPH. That's because the rolling resistance is really very low AND the cd was (at the time) the best on a production model.



And back on topic. Random curb weights. Similar sized cars.
A 2014 Focus.. 3223 lbs
A 2014 Prius... 3042 lbs (hatchback)
A 2014 Prius-C 2500 lbs
A 2002 Prius... 2765 lbs
A 2002 Focus.. 2598 lbs
A 1976 Pinto... 2590 lbs ( sedan, V6)
A 1964 Mustang 2445 lbs
A 1958 T-Bird.. 3897 lbs
A 1953 Nash... 2400-2685 (Nash Rambler)

It occurs to me that the beefing up of the sedan is probably related to the sales pitches of SUVs where they claim that the SUV is big enough to do every job. In the last 3 years there has been a resurgence of smaller models along with the bigger ones. The new Chevy Spark is only 2269 lbs. The Scion line has some little dinkie cars available too.

Dan

A.K. Boomer
07-27-2014, 06:14 PM
Your right for what they move and how much they can carry they are very efficient when it comes to that, and the reason why the 18 wheeler is not all that bad of a comparison with the average automobile is due to the fact that it has both lots of wheel friction and a pretty piss poor drag coefficient, looked it up yesterday and it was something like .90 with out the top air dam...

according to Willy's graph and the info I found on automobiles the paths at which the two converge is within 5mph --- close enough for what were talking by a long shot... and it's all you need to know as anything beyond and air drag starts RADICALLY taking over...

fact is - is even with a prius it takes copious amounts of extra energies to go from cruising at 50 to 75 MPH as the chart shows,,,

and that's just a given and simple law of aerodynamics that cannot be logically opposed or debated...

danlb
07-27-2014, 07:07 PM
fact is - is even with a prius it takes copious amounts of extra energies to go from cruising at 50 to 75 MPH as the chart shows,,,

and that's just a given and simple law of aerodynamics that cannot be logically opposed or debated...

Yep. I can attest to that. I've put 130K miles on one, and the mileage is definitely better at a steady 55 than it is at a steady 75 on the same road and same conditions. On the other hand... my Prius at 75 gets better than 4 times the MPG of my F150 at it's best, so I don't feel too bad about wasting a few gallons on occasion.

Dan

boslab
07-28-2014, 12:16 AM
I had noticed all European cars getting more and more alike since wind tunnels were put into use during design, they all look like jellow moulds
Mark

thaiguzzi
07-28-2014, 12:32 AM
Jeez. 12 pages on why crappy cars are heavy... You guys got nuthin' better to do? Lets change tack - why are Hardley Dangerous's (HD) so heavy?

J Tiers
07-28-2014, 12:53 AM
AK... I'll try ONE last time.....

A) Nobody denies the effect of air drag..... the whole point is that with different vehicles the crossover point will vary... That's just a fact..... If the car looks like a flat plate 6 x 6 feet, it is going to be a pig no matter what, and it will directly follow a drag rule at any speed, , it's likely nearly all drag..... But you take that SAME 6 x 6 plate, and put even a standard nose on it, and taper the back , like a regular "car"..... it's going to be a lot better.

Don't get trapped into the idea that cross section tells the whole story. You already equated a long somewhat tapering nose plus sloped windshield with a more nearly flat-fronted VW van having a larger cross section, almost flat back, and a 2 foot shorter body.... so your credibility here is not super high... Maybe if you compared it to a T5 transporter, it might be a little closer.

No use talking about "average cars", eitehr, if you mean a specific vehicle.....

There may be other effects unrelated to anything we are discussing that affect the fuel mileage. But is those were serious effects, I'd expect to notice them in the data.

B) It's no use stammering ans sputtering about physics and laws that as "just what they are", when there is data to show something that you don't think should be so. You ONLY HAVE two choices..... either you can discredit the data, OR you can explain why the data shows what it shows.

I have 160,000 miles of data on fuel mileage, and it does not support the idea of dominant and overpowering effect of drag at highway speeds cutting fuel mileage by radical amounts. It just does not show up in practical operation of standard vehicles I have owned.

I estimate that something between a 5% and 10% real change is detectable, due to variables of all sorts in the trips. Evidently the drag effect is under that, because it seems to get lost in the "noise".....

If my mileage was cut from 25 to 17, I'd see that immediately..... But it has NOT happened.

I have more data than than that if I count in other vehicles that show the same behavior. Data that has already detected and identified things like change of gasoline formula....weather changes like wet roads, strong headwinds, etc, data that corresponds with the average distance to low fuel light on the same roads....so it is validated data.

You have stammering and sputtering about how "it can't be so....because , well, it just can't". And a few unsupported claims of the drag coefficient of a vehicle you have never seen.

Data is winning that one..... by a mile.

C) I have never OWNED a car that was a real pig..... The Saabs all were in the 35 mpg range, but were likely to have very good drag coefficients (Saab 96). The Volvo wagons are long, low, and should have a decent drag coefficient, they have always gotten 27 or so mpg at any reasonable speed. So I have no data for a car that really DOES get rotten mileage at as low a speed as 75 mph.

D) Suppose the crossover is 50 mph..... That is the speed at which friction and drag are EQUAL..... so halving either one makes only a 25% difference..... It is not as if as soon as you reach that speed, suddenly the drag is the whole story..... NO, that will be at a higher speed where the drag is perhaps 3.2x the friction.

So the idea of a 4x increase of fuel use is not supported..... first take half, due to the reduced travel time.... then halve again, because the effect is diluted by the equal friction. You can argue that friction uses more fuel, and that's true.... but the dramatic increase is supposed to be teh drag, and it is diluted to half....

Net result is that drag effect is 25% of that expected, max, and there is an increase of friction (assuming the prof is correct for a car or light truck as well as for an 18 wheeler). That's a considerably lower effect, and might easily be masked by any num ber of other things.

E) But friction is increasing linearly..... (per the prof, although I have doubts with regard to non-18 wheelers) and if so, that pushes teh "drag is dominant" speed just a little higher.... not a ton, just a bit. Every bit makes a difference.

Now, I do not doubt that you will again be repeating that prof so and so says it can't happen..... or whatever... And repeating the tired old lecture about how I need to learn this or that "reality".....

But I'm not claiming over unity here, just that there is no support for the drastic drag effects in good data that I have. The explanation must lie elsewhere.

It might be more profitable to determine why it DOES happen.... The data is there, and has proven reliable..... the question is to explain it, and not go on reminding us all how the bumble bee really cannot fly.....

boslab
07-28-2014, 02:12 AM
Discounting bumble bees and drag etc, also the weight they must have sticky tires and super dense petrol and obese drivers and several anvils in trunk and a big trailer with a mill lathe drill and ironworker behind
Mark

PStechPaul
07-28-2014, 02:23 AM
Just as my own "sanity check" I computed the HP needed for a default vehicle based only on speed. It takes 8.8 HP at 50 MPH and 18.2 HP at 75 MPH. So the argument for higher speed=more drag=more HP is valid. But this assumes a perfectly level road, and other conditions, and the corresponding fuel usage figures tell the story that there is much more to take into consideration. The power figures correspond to 131 and 183 Wh.mile, and should show up as 30.6 vs 21.8 MPG (or some similar ratio).

But there is always some acceleration involved, and without regeneration, it can be considered a positive number, equivalent to perhaps a 1% grade. In this case, the numbers go to 11.8 and 22.8 HP, and 174 or 227 Wh/mile, or 22.9 vs 17.6 MPG. You may begin to see where the fuel consumption difference becomes less dramatic as acceleration is introduced as a factor. But there must be other other factors that even more strongly influence the numbers as reported in real world experience. I think this has much to do with the fact that automotive engines are designed with ten times the power that is really required, as can be seen above, and the efficiency charts are rather unclear at such low levels. Electric motors are much more linear beasts, and are quite predictable at such low levels. An ICE may have efficiencies that vary by an order of magnitude from light throttle to WOT, and the best torque may not be available at other than a very poor efficiency point because the engine is basically designed for high end performance and not so much for cruising.

This has been an interesting discussion but it seems to be getting silly. EPA estimates and customer reported data and anecdotal evidence based on individual vehicles are very likely skewed and highly variable, even when best efforts are made toward honest reporting. It is often found that driver technique is a greater factor than any other, and that may be the case here. One certainly might drive differently at 50 MPH compared to 75, even subconsciously.

dian
07-28-2014, 07:46 AM
"It takes 8.8 HP at 50 MPH and 18.2 HP at 75 MPH."

how did you "compute" that?

J Tiers
07-28-2014, 08:38 AM
"It takes 8.8 HP at 50 MPH and 18.2 HP at 75 MPH."

how did you "compute" that?

It looks very like a simple application of the drag formula.... ratio of speeds squared times the lower number.... Possibly with a slight correction, since the straight formula comes up with a bit higher number.

the original number looks like a table value for a "generic average" vehicle.



This has been an interesting discussion but it seems to be getting silly. EPA estimates and customer reported data and anecdotal evidence based on individual vehicles are very likely skewed and highly variable, even when best efforts are made toward honest reporting. It is often found that driver technique is a greater factor than any other, and that may be the case here. One certainly might drive differently at 50 MPH compared to 75, even subconsciously.

There are definitely a lot of factors. MANY more than simple drag calculations.

And of course a "default" vehicle may not be the same as a "real" vehicle....

HOWEVER.... I take very strong issue with characterizing well over 14 years of *logged data* as "anecdotal" (including several vehicles). Particularly when the logging was not done with the idea of proving anything... it was just taken as plain data, as has been done with every vehicle I have ever owned (and as my family has always done since the 1960s).

"Anecdotal" refers generally to the classic "I know a guy who...." type evidence.. To undocumented reports, etc. To single unrepeatable cases. To information based not on facts but on hearsay.

You may consider the existence of a "single case" (i.e. it's all concerning one vehicle, or a very small sample) to meet a somewhat constrained definition of 'anecdotal". But a real "anecdotal" report would be more like "I got 50 mpg on my last tank of gas".

When a person has documentation for many many tens of tanks of gas, that is much more accurately termed a "body of evidence". Each "case" is a tank of gas... not a vehicle. And when the data was simply read off of dials and signs... so many gallons, so many miles...type of gas, date, where bought, price per gallon... it's hard to claim bias. Calculating mileage based on tak fill and miles is a consistent and known calculation.

Unless, of course this is all a vast conspiracy to hoodwink AK...that started before the internet did....

Aside from that, I tend to agree, driving habits are much more variable. I tend to drive in such a way as to get very good mileage, always have. For a long time I had a manifold vacuum gage on the dash (in another vehicle) and it stuck with me.

I would not be surprised to see good mileage... I am sometimes surprised to see better than average, or worse than average mileage, generally traceable to mechanical faults or oddities about the gas (Kokolene).

See yah all.... I got other stuff to do

Glug
07-28-2014, 09:07 AM
Just as my own "sanity check" I computed the HP needed for a default vehicle based only on speed. It takes 8.8 HP at 50 MPH and 18.2 HP at 75 MPH.

Nit: shouldn't the units for constant speed be expressed as Force (torque, newtons, etc), and not HP? I'm rusty at this stuff, so I could be wrong - and I surely don't want to derail this thread down that pedantic rathole.

The 460 in my truck produces a lot of torque, even at idle. A certain amount of torque is required to maintain 50mph, and a certain additional amount is required for the rpm, and additional, drag necessary to maintain 75mph. I'd suggest the base inefficiencies, combined with the baseline torque at any rpm, might mask some of the expected higher fuel consumption as speed increases. The engine consumes a lot of fuel even at idle.

In the late 90's I wrote a chassis simulator that used torque curves (simulated or actual) to estimate vehicle performance. The model included aerodynamic drag, implemented from the formula found in Milliken and Milliken, _Race Car Vehicle Dynamics_.

/* AERO DRAG
/* Force = .0025 * Cd * A * V^2
/* A = frontal area in square feet
/* Cd = Coeffecient of Drag
/* V = Air velocity in MPH
/* Assumes standard air temp and pressure

lynnl
07-28-2014, 09:45 AM
-...... and I surely don't want to derail this thread down that pedantic rathole.



It's been a long time since I laughed this hard! :D :D

dian
07-28-2014, 10:05 AM
btw, do i get any kind of bonus, a free issue maybe, if this is going to be the longest thread ever?

also, looking at the dyno sheet of one of my vehicles, the drivetrain loss at 75 mph is 7 hp. the hp used at a certain speed can easyly be determined by measuring decelaration, e.g. fro 80 to 70 mph.

if glugs formula applies, then, for example:

a = 25 ft2
cd = 0.5
v2 = 5625
f = 176 (what?)

if pounds (= 5 newton), then 5 x 176 x 33 m/s = 29 kw.

so drag would be 5 x drivetrain loss (incl. rolling friction and accessories) at 75 mph. quite weird.

RichR
07-28-2014, 10:09 AM
btw, do i get any kind of bonus, a free issue maybe, if this is going to be the longest thread ever?
You have a very long way to go to catch up to the Shop Made Tools thread.

dian
07-28-2014, 10:29 AM
its a pity thats still a thred, because its "unsearchable".

A.K. Boomer
07-28-2014, 10:39 AM
AK... I'll try ONE last time.....

A) Nobody denies the effect of air drag..... the whole point is that with different vehicles the crossover point will vary... That's just a fact..... If the car looks like a flat plate 6 x 6 feet, it is going to be a pig no matter what, and it will directly follow a drag rule at any speed, , it's likely nearly all drag..... But you take that SAME 6 x 6 plate, and put even a standard nose on it, and taper the back , like a regular "car"..... it's going to be a lot better.

Don't get trapped into the idea that cross section tells the whole story. You already equated a long somewhat tapering nose plus sloped windshield with a more nearly flat-fronted VW van having a larger cross section, almost flat back, and a 2 foot shorter body.... so your credibility here is not super high... Maybe if you compared it to a T5 transporter, it might be a little closer.

You want to try and hammer on me about credibility? seriously? well - ok here goes...
My credibility throughout this entire mess is flawless, your the one that's continually "missing the big picture"

I guess you think I just brought up the vanagon to be cruel --- I mean --- your going on and on about how terrible it is drag wise... ( BTW thank you for that! ) and how im way off in my comparison,,, Are you aware it has exactly the same drag coefficient as YOUR TRUCK?... .44 http://en.wikipedia.org/wiki/Automobile_drag_coefficient that's why I used it as an example ---- Hows that credibility thing working out for you JT? I mean this is your whole basis for trying to discredit me?... ooops,

oh but I know --- you have the magic cap... Well --- I believe iv also just covered that and you must have missed it too,,, it's just right up above when I asked you if you thought your truck magically transformed itself into a vehicle that had a lower drag coefficient than one of the best in the bizz --- the toyota prius, incidentally it's .26 and incidentally the prius takes a big hit in fuel economy along with everything else tested in the batch after 50mph --- so drag coefficient does not mean all that much, so, not only have I pinned you down on your truck not being that great to begin with, your big ticket out of this mess, iv also pinned you down on it not mattering very much one way or another,,, http://www.mpgforspeed.com/different_cars.png

credibility you say? damn, just keep talking...






B) It's no use stammering ans sputtering about physics and laws that as "just what they are", when there is data to show something that you don't think should be so. You ONLY HAVE two choices..... either you can discredit the data, OR you can explain why the data shows what it shows.

And I have done this time after time, I have been more than gracious with explanations --- and most all is in your drivetain design, AGAIN --- you don't get to "cheat the laws of fluid dynamics" your truck takes much more energies to cruise at 75 as compared to 50, and if your getting the same mileage and your actually not in error then this can only mean one thing, it falls into a much better range with the drivetrain efficiency wise at 75 MPH --- gearing/cam timing/ECU and sensors are all working in harmony,,, this also means another very important thing --- if these things were all working in harmony @ 50mph instead of 70 or 75 your fuel economy would be unbelievable @ 50 --- you would be well into the low 30mpg range... once again - chevy is robbing peter to pay paul... and if you cruise at a higher rate of speed it's worth it... Do you get this? do you understand this? this is the big mystery your missing and why you continue to think that somehow your cheating the air drag at a higher speed - your not, the air drag is exceptionally more.








I have more data than than that if I count in other vehicles that show the same behavior. Data that has already detected and identified things like change of gasoline formula....weather changes like wet roads, strong headwinds, etc, data that corresponds with the average distance to low fuel light on the same roads....so it is validated data.

and that's all fine and dandy,,, and everyone else here has "data" of their own, including me, and it does not correspond with what your experiencing,,, but that's all good too JT, nobody's calling you a liar, were just trying to help you understand where it's coming from...


You have stammering and sputtering about how "it can't be so....because , well, it just can't". And a few unsupported claims of the drag coefficient of a vehicle you have never seen.

here we go again, NEVER stated "it just can't be so" and HAVE GIVEN YOU REASONS WHY IT CAN,

PULL YOU HEAD OUT OF YOUR ASS!

also - I don't need to "see your vehicle" I have the specs --- nothing magical going on JT as your somewhere between a volkwagon vanagon and a toyota prius and neither are immune to the effects of the extra drag that were talking GET IT? DO YOU UNDERSTAND THIS?





So the idea of a 4x increase of fuel use is not supported..... first take half, due to the reduced travel time.... then halve again, because the effect is diluted by the equal friction. You can argue that friction uses more fuel, and that's true.... but the dramatic increase is supposed to be teh drag, and it is diluted to half....

Im glad to see you have now added the reduced travel time into your equation, :p something you missed before remember?

It's not the total, But If you double the speed you will be using 4 times the amount of fuel that you were previously using to get over the air drag. that's a substantial increase and if it starts out at where wheel friction meets air friction the deck is quickly stacked against you - period,,, that's if all systems are equal mechanical efficiency wise, it's a very simple and basic rough draft, it takes 4 times the horsepower in air drag that it previously did - and the power has to come from somewhere... now - we could get real finicky and come up with all the extra frictional drags that are evident when LOADING an entire drivetrain @ 4 times the air friction load, (not wheel friction) and this begins to be a very large extra factor... it all equates to heat, and can be directly monitored in everything from the transmission to even the wheel bearings as they are no longer just carrying the load - they are pushing the vehicle against a force that is 4 times stronger,,, driveshafts and or CV axle assembly's and even tire temperature and the like, everything suffers and it all adds up to well beyond your primitive calculations... that's why it's so critical ---

this is why when you look at the real HP charts that include it all the results are staggering,,, it's not just the fact that the wind has this compounded effect to begin with, it's that the effect get's further compounded due to all the increased drivetrain friction,,, I won't even begin to try and calculate it - for you would need an in-depth schematic of all the working parts and layout of the vehicle... and even the types of fluids used, I have far better things to do with my time and will just look at a chart that ran a test...

So even when your just thinking the effect does not get to run the full "square" and it's just a 33% increase of the total you are again missing the big picture as to just why it's so critical and why all the tests prove it to be,,,
everything from piston skirts to connecting rod bearing to main bearings to transmission gears and bearing to what drives your wheels (and god forbid you have a bevel type rear end with hypoid fluid) and on - and on - and on,,,

that's what you have to look at, and even when you just toss in double the loading of air drag,,, or go from 50 to 75 mph, it's already been compounded simply because you only have gone 50% over the speed you were going and are now paying 100% more of the load price for that particular drag, but it does not stop there, that particular drag creates even more compounded effects throughout the entire drivetrain...

That's why when you see a real HP graph of a car (any car) going double it's original speed from say 50 to 100mph it's actually no where near the original air drag rating of double the speed quadruple the force, it's off the charts,,, it's more like 6 times the amount due to what the extra air drag does to the entire drivetrains efficiency... not critical ? I beg to differ,,,
there are severe consequences for loading an engine, that's why they put fans on radiators,,, and when your main drag starts using a fair amount of the engines total output then it's the thing that has to share the brunt in the efficiency reduction,,, compounded - it's not just it's load bu the frictional load it's putting on the entire drivetrain,,, so don't just think "squared" go way beyond,,, or even if just doubled then think much more...



But I'm not claiming over unity here, just that there is no support for the drastic drag effects in good data that I have. The explanation must lie elsewhere.

It might be more profitable to determine why it DOES happen.... The data is there, and has proven reliable..... the question is to explain it, and not go on reminding us all how the bumble bee really cannot fly.....


Beautiful, your first step to understanding, now go back and read what I wrote as to the all the reasons WHY...

that's what iv been covering all along... like I say - it either lies there or you have miscalculated once again when figuring your mileage out - and no offense but when it comes to calculations your credibility on this subject does not exactly have a stellar record... :)

PStechPaul
07-28-2014, 06:31 PM
I thought I was being fair to JT when I provided some explanation of why his data very well may show the results he has put forth. The numbers I came up with are from my EVcalculator (http://enginuitysystems.com/EVCalculator.htm), and you are free to use it as you wish or fine tune the numbers or the calculations, but I have used it to double check the actual energy and power figures that EV owners have provided, and they are very consistent with those real world numbers. The calculator shows what is theoretically needed, and then an efficiency factor must be added, but for EVs it is about 80-90%, as long as the components are conservatively rated and the vehicle is driven under "normal" conditions.

But there have been some "anomalies" when EVs are tested using what are supposedly equal conditions, and they have been much discussed and AFAIK there have been no fully accepted solutions to the apparent differences between theoretical and reported data. And this is much easier and more accurate for EVs, especially if you use a datalogger and include readings from an accelerometer. The only conclusion that made sense was that there was something more than just the average speed and the characteristics of the course, that accounted for the discrepancies. The most obvious factor seems to be the driving "style", which basically can be defined as unique profiles of acceleration and deceleration over the course, and how this may vary depending on the average speed and terrain.

For an ICE, there are many more factors, and unlike an electric motor, the torque drops off quite a lot at the low end (and may be effectively nearly zero below idle speed, while there is still quite a bit of power being applied in the form of fuel, but most of it is wasted because there is little torque and very low speed. An ICE cannot operate at zero RPM, and in order to be able provide acceleration from a stop, highly inefficient torque converters or clutches are needed until engine speed can closely match the speed of the drive train for a given road speed. The following chart from this source (http://www.epi-eng.com/piston_engine_technology/power_and_torque.htm) may help explain this:

http://www.epi-eng.com/images/Engine/ET-TqCrv3.gif

This chart does not show the efficiency at very low RPMs and torque levels that are actually required for normal highway driving, but it may be inferred that torque and power less than 5% of design specification are probably not very efficient.

OTOH, an electric motor coupled with an efficient variable speed drive (VFD) can have acceptable low speed and low power efficiency down to at least 10% rated load, and even close to 1%, according to the following:
http://www1.eere.energy.gov/manufacturing/tech_assistance/pdfs/motor_tip_sheet11.pdf

http://enginuitysystems.com/pix/Efficiency_Load.jpg

Here is some very technical information on electric motor speed/torque/power/efficiency curves:
http://www.reliance.com/prodserv/motgen/b7097_2.htm
http://texasiof.ceer.utexas.edu/texasshowcase/pdfs/presentations/d5/rschiferl.pdf

Some interesting reading:
http://en.wikipedia.org/wiki/Energy-efficient_driving
http://www.carcraft.com/techarticles/horsepower_vs_torque/
http://en.wikipedia.org/wiki/Engine_efficiency
http://www.epi-eng.com/piston_engine_technology/power_and_torque.htm

J Tiers
07-29-2014, 08:49 AM
I guess you think I just brought up the vanagon to be cruel --- I mean --- your going on and on about how terrible it is drag wise... ( BTW thank you for that! ) and how im way off in my comparison,,, Are you aware it has exactly the same drag coefficient as YOUR TRUCK?... .


If you can call me a liar..... And claim I can't manage to divide miles by gallons.... Whey shouldn't you"? You have been an insulting ass consistently, why stop now?

Well then I can certainly remind you that your claim about drag coefficients is false. And of course you will deny it yet again.

The number is for a different vehicle....one with NO CAP. No cap that fills in the big hole behind the flat back of the cab.... converting a flat surface to a longer and somewhat tapering shape.... just the length alone is a help.....

You can yammer about "magic caps" all you want. All you do is look ridiculous.... you are trying to argue a stone through a solid brick wall And it looks like the wall is in your head.

What you are really saying is "no matter what you do to a flat plate, it will ALWAYS HAVE THE SAME DRAG..... you can streamline it, but that won't change a thing....."

I don't think you quite understand HOW STUPID THAT IS.... try reading a few aerodynamics texts.... Evidently you have not.

One day you will understand, but it evidently ain't gonna be very soon.

And, after all that crap, the cap may or may not even be the issue....it's just a *possible* part of the picture.

As for the mileage? YOU don't know why it's so, and I don't know why it's so, but 14 years of data surely suggests it IS true. over 50 trips on same roads, mileage varies down in the noise.... NO SIGN OF YOUR 17 mpg... or the 7.5 mpg..... the numbers you so confidently explain to me that I am really getting, whether I know it or not....

I have had enough. I have had enough for some time now, and just because I am a stubborn Swede mixed with a argumentative Irishman and an arrogant Frenchman, I kept at it.

No more need to convince you, I probably won't even read anything more you write.... not here, anyhow. So feel free to write any sort of the condescending and insulting stuff of the type you love to write.... behind your screen name. it won't hurt me a bit....

A.K. Boomer
07-29-2014, 10:12 AM
First off JT - go back and read - we've insulted each other... so spare me the wha wah,

but your obviously more butt-hurt, im sorry - but it's been like talking to a wall and it got frustrating, and it's still going on with you stating "I can call you a liar" Geeze --- you know how many times Iv almost sent you a PM saying "you do realize im about the only one here that's trying to be on your side don't you"

I mean im the only guy standing up trying to come up with a viable explanation for what is happening with your truck so people "don't call you a liar" which you reject every time? go figure...

seems NOBODY has experienced what your experiencing and although im aware of some mild cases like this I have to admit iv never heard of such a radical span and someone still claiming identical numbers... Im assuming that's why some have immediately left the discussion - they probably were biting their tongue and didn't want to say anything bad,

They have more class than I - but for the record I never stated anything to do with you being a liar - I gave area's of potential where the gains could be hidden - if your mileage calculations are correct it's the only area where you have a leg to stand on,,, again JT - it's gearing change and cam timing and the ECU and all the sensors falling into a "sweet spot"

the magic is not happening with your cap, that is a given, your truck drags much more @75 mph than it does @ 50, and when you include all the frictional drag from loading the engine and the entire drivetrain and the double the power it takes in air drag the results are that your scale is way off --- you have increased your total HP consumption well over double yet are only moving 50% faster -
and again - that does not matter if your topper transformed your truck into a prius or it's still a wind pig like the vanagon.

like I said - your not running the truck without the topper @ 50 and then putting the topper on for the 75mph test are you? if so you should have let us know about this, if not your subject to all the same laws of fluid dynamics that everybody else has to pay...

you state "as for the mileage? YOU don't know why it's so."

your dead wrong, if your calcs are even remotely close then im telling you exactly "where" the "magic" is taking place, you then followed up with the fact that "you don't know why either" ---- your right --- so why don't you just listen for a second to someone who does?

If your calcs are correct then there's only one place to look, inside the combustion chamber... that's where your efficiency gains are as compared to a lower speed, there is no other choice for you, volumetric efficiency has changed some due to more demand but this can very well help engines that are not in their "sweet spot" as cam timing can better match up with the RPM range and if volumetric efficiency gets called on slightly and things are in sync then thermal efficiency can be improved esp. if the ECU and all the sensors are favoring lean,,, This is all you have, it's either here or youv miscalculated...
You will still use more fuel in this mode, but it is more-so on a level playing field with the extra ground that your covering...

Sorry, but you have to realize that if you claim anything else then you actually start throwing a wrench in other peoples data base, Like we should all have to bite our tongues and tip-toe around JT because his calcs buck the rest of the worlds experience,,, well be careful how you throw this stuff around cuz guess what - in a sense you call everybody else a liar with your claims...

so when someone like me - someone who has 40+ years of experience over you on subject matters like this "gives you an out" then for gods sake take it and run with it,,, and do it graciously, your trying to cling to the "superior aerodynamics" of your wind pig is testimony to you simply do not know enough about this subject matter to claim anything else,,, You should be thanking me, im the one last guy trying to make what you say believable --- and it's the ONLY area in which it could be...

Here's your trouble shooting chart I put together for you,

#1 does the physical truck (WITH CAP) use more energy per mile to travel at 75 as compared to 50 even though it arrives at its destination sooner?

answer ABSOLUTELY

#2 So why is it that it takes the same amount of fuel to do so?

answer --- there has been a miscalculation in question #2 and OR the trucks engine is operating in a much more efficient range...

see how simple that is?

and here's something for even more perspective

#3 If the trucks engine was operating at the same efficiency @50mph that it is @75 would there be an increase in MPG from the original 50mph readings...

Answer YES substantial...

any questions?

becksmachine
07-29-2014, 05:24 PM
looking back on yesteryears cars it's almost as if they were designed by aliens, and not very intelligent ones at that,,,



You sayin Harley Earl was from Mars??

:)

Dave

Alistair Hosie
07-29-2014, 05:34 PM
Usually things are heavy scientifically speaking due to a rapid reduction during the weighing process in lightness.In theory if you filled your car with feathers it would possible so light it would float along remember the Hindenberg.Albert einstein talked about things and light he pointed out that when we are born we are light but as we get older we incrementally become heavier even though we are the same person.Strangely he pointed ot that we have a reversal of this scientific wonder when we die.as within a few months we incrementally become lighter.So he proposed that it a living lack of lightness that makes things heavier.whilst a dieing and therefore lack of heaviness makes us lighter.When we become the ghosts we were before being born we are not one bit heavy.Hence the term being ligh spirited.I f there is anything else you need explain refer to Albert Bullis a direct descendent of his grandfather one stone which is what einstein means.All of this being scientific makes it apply to everything else and therefor cars when they get older they too become lighter.So your problem is that your current car is far too new and you need an older model Alistair

The Artful Bodger
07-29-2014, 11:33 PM
If your truck, car, omnibus, motor cycle produces the same mpg at 70mph as it does at 50mph you probably should stay out of high gear a bit longer.