View Full Version : turbo chargers

steve schaeffer
03-19-2003, 11:59 AM
i know this isnt a racing site, but i know a lot of machinists are gearheads by nature. my question is regarding turbos. i found a unit by warner-ishi model rhb3. it is shown in a book next to a box of film for a size comparison. it is rated for .5-1.25 litre engines. my problem is i have tried to find out where or what these units come on, if i can buy one direct from the manufacturer or what. i have emailed several turbo distributors, as well as warner ishi and have recieved no responses. it seems as though you have to have c.i.a. level five retinal scan clearance to get anywhere. that is just my experience with turbos, just wondering if anyone has an "in" with a comany. any help is appreciated. i have a summer time project coming up that involves turbo charging a 400 cc engine. but it has gone nowhere as i can not locate the unit, and i dont want to use an oversized unit because the inertial mass will be too great, and lag can not be excessive

thanks ,


extreme tractor racing

Ragarsed Raglan
03-19-2003, 01:05 PM

You need to give more details of what you expect from the turbo engine, so can you define the application of the engine a little more. Can you define where you want maximum torque, max power and where you want the boost to start. Its also good to know what maximum engine rpm will be. This is the basics for 'turbo mapping' and will define the compressor and turbine ratio's.

Don't get carried away with thinking that a turbo will be a 'top end' performance aid, one of the benefits of turbo's are that they produce power in proportion to mass through put of the engine (in other words they respond to throttle demand). This is contrary to popular belief, and as a direct result of some bad mapping of turbo applications in the past. Superchargers (when mechanically driven) produce power in proportion to engine speed, hence these units tend to give top end power at the expense of low rpm torque, which flies in the face of common concepts between the two methods of boosting.

A good starting point for you may be to visit the following website:-


There are some good calculators for basic turbo mapping available on this site.

One other point to remember is that if the engine is fitted with a carburretor, then you would be well advised to fit the carburettor downstream of the turbo (i.e. as a pressurised unit). This will prevent the compressor centrifuging the fuel out at high speed, not something which is beneficial!! This does raise the problem of having a pressurised fuel delivery system which is capable of varying the pressure delivered to a float chamber, a Malpassi unit is required to do this.


Edit note Whoops wrong url!!!!

[This message has been edited by Ragarsed Raglan (edited 03-19-2003).]

03-19-2003, 04:27 PM
My best friend works for a rebuilder that does starters, alternators, product blowers, and turbocharges. They are pretty large into turbos. He is in charge of the turbo line. If you give me a pic and serial/model info, I will pass it on to him.

steve schaeffer
03-19-2003, 04:36 PM
thanks for your information on turbo mapping etc. i didnt mention all the details, but i have considered all of the specs etc. the reason for my post is unless it is a honda civic, people cant help me get what i need.i contacted the manufacturer directly and got no response, but like i said before, i have a picture from a book about turbos, and it shows this small class of turbos which is what im trying to get my hands on. Fyi, turbo lag should be null with the class of turbo i want to use. if i try to get away with a larger turbo, i fall out of my compressor map and will be in surge sector which is no good. obviously, lag is inherent by its nature, but because of the clutch system i am using, this is tolerable in the low ranges, as clutch slip will give a dwell where the turbo can ramp up. after this point i need peak torque through the midrange . if i have too big of a compressor turbine combo, it will just lag lag lag.this smaller turbo based on the air flow throught the motor is ideal, its mass is small, its a/r ratio is ideal, and im smack dab in the center of its map. i just cant locate them. one company quoted me a larger turbo,(2.5-3.8 liter engines,) and i just laughed. im trying to superstuff a lawnmower engine!

03-19-2003, 04:59 PM
Here's a couple of links that google turned up searching on "rhb3 turbo"
Turbo 4-wheeler:
www.paatving.com/Articles/turbo400ex/turbo400ex.asp (http://www.paatving.com/Articles/turbo400ex/turbo400ex.asp)

Buy a rebuilt ($100 core charge...)
www.turbo-power.com/pricing.html (http://www.turbo-power.com/pricing.html)

Ragarsed Raglan
03-20-2003, 07:37 AM

Sounds like you've got it all covered to me! Just got to go out and find the source of supply!!

One aspect you may want to consider, if this is a competition vehicle, is doing similar to one of my colleagues at work. He races a Ford Sierra Cosworth RS500 (sprints and hill climbs), he has modified the turbo with an external electric motor drive to the compressor. This allows him to hit the switch on the dash and get his turbo on full boost whilst sitting on the start line with only about 1500rpm on the engine, and light load.


steve schaeffer
03-20-2003, 08:02 AM
rr, thats a unique one! never heard of that. im not going to go that route though. i wouldnt want to spend the money on a motor that could spin that fast, nor the engineering involved to connect it, probably need a sprag clutch or something. amazing though. what will they try next? heh.

steve schaeffer
03-20-2003, 08:06 AM
lunken, good links thank you. i need to get googlin.

03-20-2003, 02:14 PM
Glad to help. I gave the search terms because I tried several combinations and those gave the best results. It's a trick to get Google to give just enough results, but not too many...

03-20-2003, 07:24 PM
RE:........ he has modified the turbo with an external electric motor drive to the compressor. This allows him to hit the switch on the dash and get his turbo on full boost whilst sitting on the start line with only about 1500rpm on the engine, and light load.

My old 1966 turbocharged Corvair, 164 CID (2.69L), 180 HP compressor turned about 10,000 at idle and 80,000 RPM at WFO. How does your buddy get his electric motor to turn the compressor (probably smaller and therefore spinning even faster!) up to speed? What speed does it turn when he drops the clutch?

FYI the old (1982), 650cc, four cylinder, Yamaha 650 Seca motorcycle had a turbocharger and at 11 PSI of boost and the motor turning 7500 RPM the turbo was turning 250,000 RPM. That is NOT a misprint. If I recall it was that same tiny , RB3 Ishi/Warner turbogharger too.

steve schaeffer
03-21-2003, 08:12 AM
kinda defeats the purpose of "free"horsepower.

Ragarsed Raglan
03-21-2003, 08:26 AM

It just happens that part of our business (the EV branch of our group, EV standing for Electric Vehicle) is high speed DC brushless motors, the largest of these is 110Kw 15Kg weight and run at 20,000rpm, the smaller ones are in the 25Kw range and spin at upto 80,000 rpm. We even do some smaller still that are gearchange actuators for fly by wire that are geared to well over 100,000rpm and can gearshift in 4 millisecs (faster than either pneumatics or hydraulics). These motors run on 300V and above. We did the electric hub motors for a Chrysler concept car a number of years ago. I'm afraid I can't reveal too much as a lot of this is sensitive information.


Forrest Addy
03-21-2003, 01:01 PM
It's hard help you when you play your cards so close to your chest. I can see why you've had problems getting info from the manufacturers.

So far we have "supercharging" and "Honda Civic" and your frustrations with directly dealing with turbo manufacturers. Nothing about cam, carburation, stock, modified, strong parts, RPM, service, reliability trade-offs; there's very little to go on.

Lemme give you some background.

People expect a lot from superchargers. The problem is, physics frequently frustrates these expectiations.

Failure to understand the physics of superchargers leaves you at the mercy of people who claim they do and want to either sell you one or have you buy into whatever line of nonsense they're spouting.

There's no-one who's taken a harder look at superchargers on piston engines than the military and aircraft engine manufacturers during WW II. No expense have been spared and experience gained is preserved in librarys. There's little theory in today's engine supercharging niche that wasn't developed in this era. Subsequent advances have been made because of manufacturing, computer modeling and new materials.

Airplane engines operate in a somewhat different regime than automotive engines but the information gained back when is applicable to present-day piston auto engines. Superchargers increase charge density in the engine cyclinders. The more fuel/air mixture is stuffed into the cylinder the greater the expansive force of the conbustion gas acting on the piston. There's a figure associated with this BMEP - brake mean effective pressure.

Supercharging increases engine torque. Period. Increased torque at a specific RPM results in increased HP in direct proportion. Since supercharging improves engine "breathing" associated benefits include a potential for effective operation at higher RPM. Increased torque at higher RPM results in HP figures to delight any testosterone secreting mammal. It's also an excellent way to scatter engine parts.

Supercharging may be mild or massive depending on the end use, reliability, budget, and mechanical strength of the engine. Much can be said on the subject of supercharging engines but when all is said and done self-appointed experts and ICE engineers all agree: optimizing a supercharger to an engine is ultimately more dependent on tinkering than calculation.

A supercharger is an air compressor and it requires power to compress air. As the weight of charge increases via supercharging the HP demand of the supercharger increases. Thus a significant fraction of the engine output is required to drive the supercharger. Nothing is free. Even the exhaust driven turbo chargers draws power normally wasted from the exhaust stream and thus increases exhaust back pressure.

Further, compressing air heats it. You can stuff less warm air in the same volume than cold air. If the supercharge pressure is high enough an intercooler is required for safe combustion and to take advantage of the potential power increase.

The increased HP to drive the supercharger comes from the engine via the exhaust back pressure. Exhaust turbine driven superchargers (turbochargers) increase their boost as a complex function of the weight of flow through the engine, exhaust heat, and a number of other factors. The potential for engine destruction from the effects of turbocharger runaway overboost is such that waste gates sensing boost pressure are installed to bypass exhaust gas thus "linearizing" boost.

Materials and manufacturing advances have sparked developments in recent years but don't expect miracles. If you're looking for big HP in a small engine and a pre-engineered kit doesn't seem viable, you're going to have to do some studying. If you don't understand the basic concepts it's very difficult to relaize what's possible and what isn't. If you're unable to speak the "engineering-ese" you won't be able to articulate your questions in a way busy engineering types can readily understand and respond to.

Manufacturers are normally thrilled at the prospect of selling their products. Denying a purchaser info is not in their interests. They may be reluctant to give you pricing information becuase they have contracts with their distributors.

This is not to say you can't purchase direct from the factory at a substantial discount a turbo for an "engineering prototype" but you'll have to sound plausible as a kit developer or whatever when you approach Warner Ishi.

As for "Zero lag", that's careless talk. You will always have lag in a turbocharger because of the rotating mass and the time taken to accellerate it. The lower the rotating mass the quicker it will accellerate to boost RPM. If the mass is low enough the lag may be imperceptable but it will still be there.

Lastly, adding a turbocharger is only part of the problem of increasing an engine's output. The cam, carburation, valves, racing class rules, and a dozen other parts and factors (including the depth of your wallet) have to be balanced together if you're going to gain the most bang from your engine.

If your HP requirements are transitory (passing, drag racing) NO2 might be a better choice than a turbocharger.

[This message has been edited by Forrest Addy (edited 03-21-2003).]

steve schaeffer
03-21-2003, 04:20 PM
forest, i appreciate your information. let me stop you before you post another long reply. i did not need your explanation of how a turbo works, how manufacturing distributors work, how a turbo has lag, etc. i am fully aware of all the associated details. my question was finding a very small series of turbo such as the one i have seen and the associated documentation. i did not ask warner ishi if i can buy it direct, i was mereley asking for information on the said unit for available turbine/compressor a/r ratio's, draw through or blow through seals, etc. etc. no one i have spoken to can get me the info on that. i can get all the info i need for a rayjay or warner or whatever else, if it goes on a common application and the information is readily available, hence the reason for my post. i did not go into all my specifications, what size cam, compression, powerband, etc, for the sake of simplicity in my question.". Fyi, turbo lag should be null with the class of turbo i want to use. if i try to get away with a larger turbo, i fall out of my compressor.... " this is meant to mean "not relevant" for the amount of lag that would be present and the range in which it would occur for my application. i fully realize that lag is an inherent phenomena in the turbo charger. i appreciate the information on this site, just dont assume i dont know anything and dump your vast knowledge of turbochargers onto my post like you are gale banks. and to answer your last suggestion about nos vs. a turbo, not into that. wheres the fun in that? please dont take this the wrong way, but i am a little defensive when i feel like i am getting answers to questions i didnt ask, because it is assumed that i dont know anything. maybe i worded my post "carelessly" , speaking casually instead of scientific. sorry for the confusion.

03-22-2003, 12:27 AM
Forrest, you took the words right out of my mouth.

I just want to install an Eaton M90 on my Slant Six. No I'm not kidding. I've already designed the adapter for my intake(Offy 4Bbl). I'd rather cast a blower intake to bolt the M90 to directly, thus doing away with the adapter, and a potential vacuum/boost leak. I can bolt a Weiand 142 to my Offy by making an adapter from 3/8" or 1/2" aluminum plate. But I like the Eaton's boost bypass for idle and cruise conditions.
Not that any of you care to hear about this. It was just on my mind.
Anyone remember the Turbodyne Superpac? It was an electrically driven centrifugal supercharger offered for sale in the late '90s. I'd still like to have one of those. Hmmmm, if I get an inverter and a couple of leaf blowers..............

Dave Opincarne
03-22-2003, 02:09 AM
Basic question for you all. Does HP/torque increase directly with air volume (assuming the same final compresion ratio) or is there some other advantage to turbo/super charging? In other words, other than engine weight what's the difference between a turbo engine and a proportionaly larger engine with a combustion chamber small enough to provide the same compresion ratio?

03-22-2003, 04:23 AM
HP out is pretty linear with air/fuel mass, modulo power to drive compressor. An intercooled turbo can generate more power
than a bigger engine w/ a higher compression
ratio since the latter will detonate due
to a higher charge temperature. Also, a larger engine cannot spin as fast as a small one, so small engines built stout w/ lots of intercooled boost will make a lot of power
given the right fuels (alcohol).

<font face="Verdana, Arial" size="2">Originally posted by Dave Opincarne:
Does HP/torque increase directly with air volume (assuming the same final compresion ratio) or is there some other advantage to turbo/super charging? In other words, other than engine weight what's the difference between a turbo engine and a proportionaly larger engine with a combustion chamber small enough to provide the same compresion ratio?</font>

03-22-2003, 09:02 PM
Some guy runs around town with a sharp little turbo hanging off the side of his HOG. No2 system if you think he is kidding and a front break that looks like it might work. go figure. Try looking for some HOG hot rodder.

03-23-2003, 05:33 PM
RE:............ In other words, other than engine weight what's the difference between a turbo engine and a proportionaly larger engine with a combustion chamber small enough to provide the same compresion ratio?

Tons of difference. First off, you DON'T want your turbo engines C.R. to equal a normally asperated one. You want it to be lower. Reason; more space = more air/fuel mixture that the turbo can cram in to it and that equals more HP. Usually it is skewed towards the top end. An engine that has a lower CR will have a longer throttle response time though.

From about 1980 to 1989 or so F1 allowed 1500cc(91.5 CID) turbocharged engines to compete directly w/3000cc NA ones. Within a few years you either had a turbocharged engine or were relagated to the back of the pack. The best 3000cc (181CID) NA engines made (then) around 650-675 HP. The turbos made from 700 to 1000 hp depending on the boost (later actually adjustable from the the cockpit). Towards the end of that formula teams actually had turbocharged engines built strictly for qualifying. That is one lap warm up two or three laps at ABSOLUTE MAXIMUM speed and one lap cool down (actually just hope it hung together long enough to get it back to pits!). Those engines made between 1100 to 1250 HP and were ONLY designed to last five or six laps MAX.

In the late 60's - early 70's Porsche built a flat 18 cylinder motor (490 CID) as an engineeing excercise and to be used if their twin turbocharged, flat 12 cylinder (5.4 L) motor did not put out enough power. That motor(5.4L) made 1200 HP from 326 CID and could do so for short periods of time. It was usaully rated at 750 HP to 850 HP and could win Le Mans (24 hrs flat out) in that state of tune. When Porsche got out of Cam Am racing in 1973, after winning the series for two years in row they retired the 18 cyl car too. It made just over 2000 HP but was never needed.

One of the best books on state of the art turbocharged engines is "Anatomy of the F1 Racing Cars" from, I believe, Classic Motorbooks, in Osceola, Wisconsin. You need to find the one that came out in the late 80's or early 90's. I'm not sure that it is still in print though.

Neat trick about the brushless DC motor RR. I liked it!

Regards, Ken

Forrest Addy
03-24-2003, 12:02 AM
Sorry Steve. I wasn't dissing you. It's hard to determine technical attainments and the questions behind the questions from a posting or two particulalry if the starting info is sparce.

I'd suggest to anyone posting a technical question that a sentence or two discussing respectively their background, the present stituation, what they want to happen, the resources available, and the budget if germain.

If I presented too much too and basic info is its possible it will benefit someone if not the original poster.

As for your lack of info from company and distruibutor sources, I couldn't say. If your original info came from a magazine it's very possible the lower levels have little knowledge of what new products may be happening in their company's future. Then too magazines frequently garble little details and report tentative discussions and rumors as established fact. Magazines have pages to fill to attract readers and thus accrue advertizing revenue.

steve schaeffer
03-24-2003, 07:21 AM
i didnt mean to be abrasive, i was a little cranky when i wrote that, i had just got up. and yes, it is good for someone to read to benefit. any info is good info.
no hard ones,


Dave Opincarne
03-24-2003, 07:28 PM
Thanks for your response Ken, but thats a little two much detail for me, give it to me simpley. In the example you give, is the 1500 cc turbo breathing more or less air than the 3000 cc engine? As I understand it, for any given fuel displacement isn't realy what counts, but how much air/fuel gets crammed into the combustion chamber.

Interesting about the outcome of the turbo/NA outcome. I remember watching some F1 races when both types where running and recall that the NA engines had a real advantage everywhere but the straight aways since they didn't suffer a lag time. They would realy hit the brakes hard if a turbo was behind them and then take advantage of the quicker low end tourqe.

TIA - Dave

03-24-2003, 09:37 PM
Hi Dave,

Re:...........is 1500 cc turbo breathing more or less air than the 3000 cc engine?

WAY MORE AIR!!! The name of the game is getting as much air as you can into and out of a motor. Out is usually NO PROBLEM. The pistons will always push it out and the induction/exhaust piping can be used to "tune" the engine to use the weight of the air/fuel charge to actually pull out the spent gasses. This is done along with cams, head porting size and angle and length of headers and intake manifolds. Now it can all come together at only one single RPM range. You set up your motor for top end in dragsters and some kind of comprimise RPM for road racing. It depends on the tracks longest straight, number and type of corners and your transmission and final gear ratios. You always want the car to be accelarating. You want the engines to top out at the end of the longest straight (idealy)!
You can always get enough fuel into an engine but air movement and control is the name of the game.
After the turboes got thier act together for endurance and turbo lag they came off the corners like they were shot out of a cannon. Since they weighed less they also accelerated harder too! When they were allowed unlimited fuel thier higher HP made them untouchable. Figure 1000 HP in a 1800# car.

Forrest Addy
03-24-2003, 09:44 PM
Wa-a-ay back when I was a budding motor head I was interested in F-1 when it was 1500 cc NA only. There was a cartoon in one of the mags showing "trombone" tuning of the induction stacks and the exhaust complete with flyball governor Rube Goldberg operating mechanism. Hilarious. I had it in my tool box for years and got laughs all the ding dong time (never clean and reorganize your tool box.

03-24-2003, 09:55 PM

TURBOCHARGERS INC (901) 366-1646

they should be able to obtain it or cross it with a garrett for you. randy t

Dave Opincarne
03-24-2003, 11:15 PM
Ok, so torque has a more or less linier relation with air volume and the advantage of a turbo is how weight affects engine dynamics? SDDWGOSA(standard disclaimers dealing with gross oversimplifications apply)

Ken-I don't understand how a turbo can have a lower effective CI if more air is being drawn in.

-Dave (4" stroke, likes a tiny primary, 5k redline and 4.11 gears so I don't use a turbo but could use a good tri-Y header)

steve schaeffer
03-25-2003, 09:47 AM
dave O, i think you and ken are talking about two different things, static compression ratio versus cylinder pressure.
my feeling is cylinder pressure = torque. i know you like to use the word linear dave, but i dont feel that any engine is linear. they are usually kind of S curve. some i guess could be more linear than others, but usually once the valves start floating your horsepower goes bye bye. haha. a motor is a pump, agreed? a given motor will have a given volumetric effiency. the engine in the car you drive has a v.e. of about 75% (generic) with improvements in cylinder head, cam timing events and other modifications, it is possible to exceed 100% V.E. most prostock engines,nascar engines are over 100. heres where a turbo charger excels above naturally aspirated. V.e. is drastically improved because in effect " you are pumping air into the pump(motor)" if that is the simplest way to explain it to an engineer, i dont know what is. also, its not just high volume , but also pressurized. 8 psi of boost run in an engine with 9-1 static compression ratio produces a given amount of cylinder pressure, which equates to torque. horsepower scales upwards with boost pressure. the more boost you run, the more hp you will make. the limiting factor now is detonation in the motor, you ever see those pulling tractors with three stage turbos on them? they are running gobs of boost. they use water injection to cool the intake charge and quench detonation. amazingly they are almost using more water than fuel in a pull. thats why when you see one of those old allisons pulling, everyone gets back, with all that boost, when those 12's let go, parts go a flyin! there are many other aspects of the turbo, and i am no expert, i figured i would share some generic info for everyone.

Dave Opincarne
03-25-2003, 07:19 PM
OK, I got it compresion ratio doesn't take into account how well the engine breaths (partial vacum at the bottom of the stroke?) and the turbo effectivly improves intake efficiency to greater than 100% as compared to a larger NA engine Yes?

I know power curves aren't linier, I'm just trying to grossly oversimplify in order to get at the nub of my question.

Thanks All.

steve schaeffer
03-25-2003, 08:02 PM
and the light goes on, bling

03-25-2003, 08:42 PM
I recall a honda motorcycle using a tiny turbo, less than 1" diameter, I think. I wondered at the time if it wasn't possible to gate the inlet to the turbo, and drive it with a brushless motor, using an ironless armature. The limitation on speed would depend on the bearings then, and if attached to the turbo shaft, that's solved, also. Electronics would have no trouble keeping up, even at 250 krpm. I mention the gate firstly since it would allow the turbo to come to speed, and remain there, essentially in a vacuum, before any flow was req'd of it. Secondly, I brought it up because no one else did. Is it just a bad idea?

steve schaeffer
03-26-2003, 09:14 AM
no darryl, your idea is very intriguing. im just trying to figure out how to get the money to buy the turbo charger first. haha

03-27-2003, 05:16 AM
You sick , twisted, person!

Don't you know that is just the right size to make into a MAPP gas jet engine for a bicycle? Should be able to hit at least 60MPH with it.

Wish I had I little turbo...Sniff, sniff

steve schaeffer
03-27-2003, 08:32 AM
actually i am sick and twisted. this is for my little "fx lawnmower racer" just a little something for my home use. haha i wonder, because it already does 60 mph, will put you on your back in a flash, and makes you pee blood the next day because @60 ;with no suspension, running over a small bump makes your head spin. haha.

03-27-2003, 08:00 PM
Hi Forrest:

RE: ..............There was a cartoon in one of the mags showing "trombone" tuning of the induction stacks and the exhaust complete with flyball governor Rube Goldberg operating mechanism. Hilarious.

They are called venturis or velocity stacks when they are on just about on all racing NA fuel injected engines. Whenever an engine is being run on a dynometer (called a "Pull" BTW) they will always have a venturi on their inlet NA, turgocharged makes no difference. It is used to smooth out the centrifigual forces on the column of air as it enters the intake and is suddenly stopped by the intake valve slamming shut. FYI a Big Block (500 + CID) turning 6,000 RPM will make about 25 - 30 more HP with a venturi than w/o one! At least on the dyno.

Early on the racer/tuners found that velocity stacks made more HP both on the dyno and the track. They just naturally assumed that it would do the same on the exhaust side. They were mistaken. It was later found that the diameter and length of the exhaust pipes, RPM, piping bends and having each side of the engines exhaust (V-8's) meet in a "cross over" would have the biggest effect of scaveraging the exhaust. Even the intake manifold pleneum (sp)size affected it.

Back in the late 1950's my Dad worked for Ford Motor Co. in Dearborn, Michigan in the experimental engine division. His job was to take the experimental motors (literally handed to him a piece at a time from the machine shop[s]), assemble and tune them and do runs (pulls) on them to determine their torque, HP, and fuel consumption. A production engine (then) was run at WOT for 100 hours and then disassembled to check for any signs of wear.

One of the experimental motors that Ford was working on at that time (1958-59) was the "Indy 4-Cam" engine. He had one all set up to run one day and he had me wait in the car until all of the "straw bosses" went home. He snuck me in the back door one night and fired one of them up. The engine "cells" then were all steel about 10' X 8'X 9' high completely enclosed. The exhaust went out the top of the cell as I recall. He needed to make some small adjustment and he let me in the cell while it was running. After he made the (fuel adjustment?) whatever he reached over and started to rev up the motor. When that motor hit a certain speed (sorry I can't recall what speed) suddenly your pant legs and shirt sleeves began snapping back and forth at the exact same speed as the air in that cell. That engine had caused (tuned)the air in that room to hit a harmonic and EVERYTHING move at the same speed! You could actually feel it. It is somthing that I'll never forget.
Regards, Ken

03-28-2003, 08:56 PM
Steve I would start with CB performance and also try dennis kirk. google it...
archie =) =) =)

<font face="Verdana, Arial" size="2">Originally posted by steve schaeffer:
i didnt mean to be abrasive, i was a little cranky when i wrote that, i had just got up. and yes, it is good for someone to read to benefit. any info is good info.
no hard ones,


03-31-2003, 08:11 PM
No replacement for displacement, I put a 900 kawasaki sectioned frame into a suzuki 4 wheeler
front, and a honda big red rear axle. Knobs on the tires lasted less than 5 minutes.

04-01-2003, 04:56 PM
The old Hot Rod addage still applies, "When in doubt, bore it out"!

However, a turbocharger is only used when its needed so you don't have to pay for the loss of mileage and more pollution (from a larger displacement engine) when its not in use. It has been found when the turbocharger's compressor just sits and spins in a "no boost condition", around 10,000 to 25,000 RPM the mileage will actually GO UP! It is believed that this phenomenon is caused by the turbos action of:

1) The impellor's blades physically beating (mixing) the air/fuel charge up better (more homegenous) and

2) Having the fuel/air mass "swireling" and not just simply "tumbeling" (falling) into the combustion chamber.

Simple tumbeling is kinda like pouring a bucket of sand into an open window. It just piles up on the base board. The turbos action even when its just "idleing" is desireable as hell in getting more mileage (and lower emissions!) out of ANY engine. Now when it starts to produce boost you still keep these good points AND then you get a far denser mixture and the HP/torque can go right out of sight. Along with the pistons, rods, and bottom end if you're not too careful!

Do any of you recall the small diesel engined VW Rabbits (and small VW P/U trucks) of the 80"s. If memory serves they were about 1200cc (73 CID). Stock they got 35 to 40 MPG and couldn't merge onto a freeway safely. Bog slow acceleration! Diesels will ALWAYS get better mileage than a comparable sized gas engine because they compress the fuel/air charge so much harder. More compression = more HP; simple as that. They can go as high as 23:1 CR. When after market turbochargers were added to get better performance out of those little VW's (a NA diesel powered car is a stone and a 73 CID one will grow moss!!) they suddenly found that their milage went up as high as 75 MPG when they were NOT under any boost! Talk about a Win - Win situation!

FYI the highest horsepower NA gas motors (for their size) that will last for 1000 to 2000 miles using just pump gas and a 4-barrel carburetor are the 366 CID Nascar motors. Presently they can make a little over 650HP but have to run a CR as high as 15.00:1 or even 16.00:1 turning as high as 10,000 RPM. There is some serious engineering to make that much HP and get them to hang together at that speed. Trust me!

04-10-2003, 06:18 PM
Steve, have you tried http://www.ihi-turbo.com/

04-12-2003, 05:06 AM
Part of the reason diesels are more effecient is because they actually use a fuel with a higher molar heat value heavy oils like #2 fuel produce more power in highway tractors than the lighter #1. The #1 flows better in the cold because there are less paraffins than the #2 fuels. At cold temps the heavier fuels "gel" due to the waxes present. By removing the waxes in the fuel, they depress the pour point of the fuel at the cost of lost power.

There are no free lunches - everything is a comprimise. Propane injection in diesels is akin to nitrous. Because propane has about 138 Rankin Octane Number (RON, MON is Motor Octane Number) it performs better under very high compression (diesels). These is why propane conversions do not get better fuel economy than they should as they are often slapped onto a 8:1 smog motor. It was mentioned gasoline was a good fuel - not so, as RPMs increase, the combustion rate of the fuel limits maximum RPMs long before its energy potention is realised. Alchohol, is much like propane - they both have a extremely fast flame front, but require high compression to get the power out. Nitromethane is used to get reciprocating engines above the 10,000RPM as it has a flame velocity far in excess of 60,000mps (Nitroglycerin is over 500,000mps).

This is why as the speed and power go up we move from gas to methanol to nitromethane. Some racers put nitromethane in the 2 strokes for added power - the danger in that is Nitromethane polymerizes almost all 2 cycle oils (the reason Castor oil ss used in Nitro fuel for model airplanes is unaffected by Nitromethane) - some synthetics can stand up to 10% Nitromethane before they polymerize. It should be noted that High performance BB SP racing model airplane engines can get over 6HP/cid naturally aspirated (60-80% nitro)! Top fuel blown dragsters get around 5HP/cid for comparison (3000HP/600cid).

04-12-2003, 09:37 AM

Efficiency should NOT be in any way related to the fuel. It should be the power out vs power available, and is a dimensionless number.

That means that if a fuel with more available energy is used, the power out should indeed go up. But the ratio of avaliable to output should ONLY be afffected by the engine's ability to utilize the energy of the fuel.

So a perfect engine would be equally efficient on alcohol OR gasoline OR bunker 2. The actual power output would be dependent on the fuel.

04-12-2003, 12:35 PM
Perfect does not exist. THE only way to get equal power out of a wide variety of fuels is to use total mass to enegy conversion. So far we don't even have Fusion, never mind.

My point was that fuel does have an important key in effeciency - the motor needs to be optimised to that fuel for highest performance. Im my defense, Alcohol and diesel have been blended and produces considerably more power than just the #2 fuel oil by itself can produce (in the same motor). Stuff looks like liquid bear poo. They still have not determined if the injectors and pumps can take this abuse - they aded a surfactant to make the alcohol blend with the oil.

04-12-2003, 11:25 PM
I think you missed the point.....

The efficiency is how well the engine uses the available energy.

If one gives more total energy output than another per gallon, or per KG or whatever of fuel, that is irrelevant UNLESS they are both using identical fuel. Not both using gasoline, or whatever, but IDENTICAL gasoline.

Otherwise you have no idea what the comparative efficiency is. You are measuring with two different "measuring sticks", as fuels vary in available energy per unit.

Even alcohol, which appears to be a lower grade fuel, apparently has a slight advantage per unit weight. Trouble is, it is pretty light stuff, so volume is bigger. Therefore, mixing alcohol with gas lowers the energy density on a volume basis.

Your fuel mileage per gallon reflects that on a "gasohol" fuel as is used in the states. My truck will burn "E85", 85% alky and 15% gas (available in 2 pumps here). But my mileage will be worse on it, gallon-wise, due to the poorer energy density.

You have to determine how much available energy there was in the fuel used, and how well the engine converted that to mechanical output.
Only then can you state an efficiency, unless you are not talking about the same sort of efficiency.

[This message has been edited by Oso (edited 04-12-2003).]

04-13-2003, 01:01 AM

I am not really arguing with you, but I would like to clarify my thoughts.

What I was trying to get across was that some fuels are better choices than others for differing reasons. Today's gasoline is almost stoddard solvent - very low octane, and worse yet, they add butane in cold weather to make it more flammable for cold starts. If the daily temperature hovers close to 32F or 0C the butane makes the fuel line vapour lock. So fuels here in Alberta are not a constant formula during winter - they blend daily based on 3-4 day weather predictions. The addition of oxigenates (MEEP or Alchohol) is there to aid in cleaner burning fuel but cause injector and oil life problems.

In diesels Cetane is important - a diesel that blows white smoke (even though the pump is set up correctly) is a direct sign of low Cetane in the fuel. The cetane advances the ingnition curve and makes cold weather starts easier for diesels.

As complicated as engines have become, fuel is a major issue. Fuel effeciency of the motor is also dependant on fuel quality and its molar heat value. You cannot dismiss one or the other in the search for effeciency - they are co-dependent.

04-13-2003, 09:44 AM
Oh, well, of course an engine is designed to use a certain fuel type, in general.

But in essence they all are burned, so the differences are in the mechanical arrangements for fuel handling, and the effect those have on usability of certain fuels. Cetane rating is important for diesel, but good diesel makes a poor fuel for a gas car. Good gas would be a problem in a diesel, as they are optimized for different things.

In the US I rarely if ever see a diesel with white smoke, unless it is construction equipment just being warmed up on a cold morning.

Mostly it is the trash collector trucks blowing thick black smoke because some bozo mechanic can't manage to adjust the injector pump, and the drivers all put the pedal to the floor. Diesels are "smoke limited" when there isn't any more oxygen in teh cylinder to burn the fuel completely.

The Feds have always let big trucks pollute like crazy (partly burned fuel= carcinogens out the wazoo) but have stuck it to the auto driver twice as much to compensate.

Of course, the auto is probably driven for 20-30 min twice a day, and the truck is on the road all day. Which do YOU think has the bigger pollution potential????

Now, the fuel additives just take up space with lower energy (alcohol), or are "pre-burned". That is what "oxygenated" fuel amounts to....fewer bonding sites for oxygen as some are already full.

Or, some fuel additives which are mandated, but are major pollutants, like MTBE. We still use it (by law) here in St Louis, but it is illegal everywhere else in the USA.

Governments are committees, and comittees are inherently stupid. You can lower your effective IQ by just being on one. This must account for the stupid laws...........

I dunno what this all has to do with turbochargers for small engines. But, since when have we EVER stayed on topic around here?

04-15-2003, 01:58 PM
Well, the turbo itself can be turned into a jet engine - you can even throw an afterburner on them. You attach a combustion chamber to the turbine side and it drive the compressor that feeds the burner. A small one on a bicycle is a squirrely ride - it is easy to get them over 60mph!

Oh, the joys of bastardizing an application to create another unconventional one! http://bbs.homeshopmachinist.net//biggrin.gif

04-15-2003, 10:57 PM
<font face="Verdana, Arial" size="2">Originally posted by Thrud:
Well, the turbo itself can be turned into a jet engine - you can even throw an afterburner on them. You attach a combustion chamber to the turbine side and it drive the compressor that feeds the burner. A small one on a bicycle is a squirrely ride - it is easy to get them over 60mph!

Oh, the joys of bastardizing an application to create another unconventional one! http://bbs.homeshopmachinist.net//biggrin.gif</font>

I found a web site about building a jet engine from a turbo, cool site. I would try one myself but I don't need another project.

I found my typo error.

[This message has been edited by gunbuilder (edited 04-16-2003).]

04-15-2003, 11:59 PM

Plus, it would make a nifty sidewalk defroster! Or BBQ charcoal ignitor...

Everyone needs on of them, eh! http://bbs.homeshopmachinist.net//biggrin.gif