No announcement yet.

Variable throttle

  • Filter
  • Time
  • Show
Clear All
new posts

  • Variable throttle

    $3.75 a gallon has even got me thinking what else can I do? I basically have a box stock 92 toyota tercel --- even though its rated by to only get 33 highway I actually do much better than that --- at 42 to 44 highway my car does pretty well even by todays standards, But, not good enough for Mwah, I achieve better ratings for all kinds of reasons, for one having a drivetrain thats got over 220,000 miles on it helps, seals lose their grip a little, gear teeth get polished in along with bearings ect.
    But nothing effects mileage more than driving habits -- and iv adapted some good ones, it takes allot of focus to keep an engine in its sweet spot and not overshoot or de-accell -- it takes slow starts and also anticipating stop lights and signs and "coasting" in (more for city mpg ratings) Even though my engine is just a little 1.5 liter it is still very responsive --- its easy to over shoot and then have to slightly back off, Iv gotten far better than an average cruise control as most of them have problems with cycling if you pay attention --- also I will out do a cruise for MPG anyways simply for the fact that some shorter hills are better to give up a little speed on and then a slow recovery on its other side rather than to "charge" up them,
    On the highway it still takes much focus to keep my engine where I want it for optimum efficiency - I do keep speeds down to the average, All it takes for my car to achieve 65 mph is a very slight crack of the throttle plate, its got to be about .175" of gas floor pedal --- a touch more and your over, to little and then you have to compensate, I have found that when I dont pay attention I actually lose about 2 to 3 mpg, Its for this reason that I built what I built this morning, its a variable throttle -- it takes way more foot pedal travel at crack/open position then it does close to wide/open, it will make it very nice to have a much smoother cruise without the jumpyness of what I had, For those of you thinking that Im trying to "trick" the engine out of its fuel please understand that thats not whats this is about (sorry I had to print that -- just used to some people not getting the point) Although It will in fact make it easier to get into the "granpa" mode esp. around town.
    I mapped out where I was going to ratio change the standard unit and then cut and welded it back together, It worked out very slick and everything works great throughout the range, Its very "feathery" at the top and I can dial in what i want much better, it also has a very noticeable progressive spring rate so if you want full throttle you have to put your foot into it to achieve it (much more pressure than stock because I was still limited to stock gas pedal travel I had to move the fuller throttle cable position to a closer radius to achieve close to stock full pedal travel) , At first I thought I might have to build a cable casing pivot because I thought the angles would drag the cable on the housing mount to much but its smooth as silk -- its got a teflon insert or lining and I also threw some fresh mobile 1 syn grease at it.
    I dont expect to see much improvement as I was already making most of them when "in my mode" -- I still may see a little -- what I expect to see is an improvement for when I forget to focus on the pampering -- now it will be more automatic, Plus its going to be hard to tell because I just switched over to mobile 1 syn. trans lube and 0w30 mobile 1 syn engine oil, they will both save -------- what surprised me also, after the oil change this morning I went to the store to pic up some grub, came back and noticed I had to set my idle down,,, Way down,,, very nice indicator...



    Last edited by A.K. Boomer; 05-22-2008, 06:04 PM.

  • #2
    Very cool idea! Especially if you have owned the car for a while. One gets to know where the pedal is. Install this and maintain your habits, sure it would help. Just keeping in mind it takes a little longer to get to speed. Can't wait to see what you come up with when you get to $6 a gallon like us
    Don't drive my 4x4 suburban much anymore.
    Cheers, Bob


    • #3
      $3.75 a gallon

      I can almost remember when gas was that cheap here.
      Last edited by loose nut; 05-22-2008, 09:47 PM.
      The shortest distance between two points is a circle of infinite diameter.

      Bluewater Model Engineering Society at


      • #4

        Was a guy on the nightly news tonight.. he is making and selling big bicycles with a weed eater engine. NEWS said $100 for kit.. I know that can't be right.. I pay more for a part for my weedeater..

        He was getting 137mpg.. I looked on the local news for the story, not there.. so I guess it was not a headliner?

        Another great idea for a home shop machinist to make for money to support his "more machines" more tooling habit.. Bicycles with engines.. Imagine the diesel they sell on ebay..
        Excuse me, I farted.


        • #5
          I used to think that mileage was very dependent on throttle finesse but I've changed my thinking. Took the wife's Toyota Solara on a 600 mi trip last weekend. It has continuous MPG readout. The big factor is grade. Hills you can barely see really hammer the mileage. A lot more throttle doesn't change mileage much, it only uses a given amount of fuel for the speed, grade and acceleration. Zero to 60 in 6 seconds, yes, 65 to 70 in a few seconds, no. Kinda like trying to walk really light on thin ice so you don't fall through.

          Want good mileage? The smallest engine that will get the job done at wide open throttle. What sense does it make to put a restrictor plate (a nearly closed throttle) on an engine. Engine has to work as a vacuum pump just to get a charge in the cylinder and then there isn't much charge to expand and do work. Over-sized engines have more friction and accessory losses. Lose, lose, lose.


          • #6

            Revise the numbers to make the playing field level... Give the mileage in Ton Miles per Gallon , not Miles per Gallon.



            • #7
              At the present rate of increase, you will be paying $10 per gallon this time next year, and $20 one year later.

              By August we should be north of $5 per gallon and rising.

              I don't know why anyone should even consider a gasoline vehicle worth repairing, let alone diddling with, at that rate.

              Let 'em rust out.

              Correction............. at the present rate of increase, 17% in 3 weeks, gasoline is projected to be $54 per gallon at this time next year.......... and oil will be at $1862 per barrel..............
              Last edited by J Tiers; 05-23-2008, 12:52 AM.

              Keep eye on ball.
              Hashim Khan


              • #8
                Diesel here hit $4.68 today. A month ago today it was $3.48 at the same station, according to my log book. Guess its time to get my walking shoes resoled and get back into shape!
                24 Hours after the above post the station with the $4.68 a gallon diesel raised it to $4.75 a gallon. Time to invent the cosmic radiaton collector, storage device and motor.
                On a strange note, the station that carries the 120 octane fuel my 1970 Trans Am runs on, just lowered the price of it from $6.79 a gallon to $6.59 a gallon!
                Last edited by RetiredFAE; 05-23-2008, 03:05 PM.
                NRA Life Member


                • #9
                  Even though its a variance within a variance (because after all a throttle is just a "variable") It would have been more appropriate for me to have named the title to the this thread "progressive ratio throttle"

                  GK man, Hills and grades will take there toll no matter what, just the matter of having to lift the vehicle vertically along with all the wind drag, Finessing a throttle does work, and depending on who's driving and their previous habits can have anywhere from mild to extreme results,
                  Having an engine small enough thats designed to run full throttle is a pipe dream in the practical world, because we only use a fraction of an engines rating to do most of the drive time (cruise down the highway) it means we have to have overkill or we would never get over any hills (or where I live up any mountains) never be able to tow anything or load anything, never be able to get out of the way when pulling out in traffic and on and on,
                  Dont want to pay the dividend of having an engine ran as a suction pump?
                  Get a diesel --- most are now designed with wide open full bore as much as they can get their pistons on, So no more suction problem --- but --- Now even when the demand is low your compressing an incredible amount of air volume just to light off the amount of fuel that 1/20th the air could have burned efficiently -- now instead of losing it to suction your losing it to uneeded compression volume, but its needed to keep the ratio up and light off the fuel, so whats a girl to do?

                  Variable displacement anybody?

                  Actually, future compromises will be more and more evident, Even in the state of colorado I could drop another 200 CC's and run a 1.3 liter instead of a 1.5,
                  Im in agreement as i think everyone would be - that up to a practical degree smaller is better, But --- you get to high altitude in the summer with a little P-shooter like mine and your thankful for the most part thats its always so much cooler up there cuz even with a 1.5 the cars such a dog that running the A/C would teeter on holding up traffic, But then again, when people have to start walking instead of driving the entire A/C argument goes right out the window.


                  • #10
                    Originally posted by J Tiers
                    At the present rate of increase, you will be paying $10 per gallon this time next year, and $20 one year later.
                    Ouch!! That would hurt.. I dont drive much anymore after retirement. We were spending about 270 a month on gasoline, easy to track cause we use a card. Thats when I was working. Its still about 270 a month!!! Next my wife is gonna have to retire to keep it down LOL Oh wait, she works outta the house, doesnt even drive to work.. Oh no, we are in trouble. Guess we are gonna have to take the kids outta school cause I think thats where the gas is going, driving the kids to school. Ill home school them, teach them how to run a lathe LOL JR
                    My old yahoo group. Bridgeport Mill Group



                    • #11
                      Originally posted by loose nut
                      $3.75 a gallon

                      I can almost remember when gas was that cheap here.
                      A gallon! we pay that per litre now


                      • #12
                        91 octane has just gone NZ$2.00/litre last night. That is $9.00 for a real gallon.
                        Damn speculators!
                        Damn polies!


                        • #13
                          Geeze Oh pete, I hope I didnt sound like I was complaining

                          Many people are adapting already and looking for alternatives, Iv never seen so many little vespa's and mopeds in my little town, Of course, whats going to happen come winter...

                          JRW's got a good point, if you do the math the little one person haulers are fuel hogs, they have little four strokes that do a little better (but I guess there gutless), anybody know of a little 50cc turbo diesel on the market?, I could see adapting that to a pedal bike and having some fun with it. Its about as close as you can get with underating an engine yet also having it have the capability of supplying much more than its standard displacement, it is the real beauty behind the turbo diesel.
                          Last edited by A.K. Boomer; 05-23-2008, 09:56 AM.


                          • #14
                            Read an article in some outdoor magazine a few weeks ago about how to get better fuel mileage in your vehicle. Two of their points stuck in my head.

                            The first was just plain stupid. They said to ignore the tire pressure information supplied by the vehicle manufacturer and to always run your tires at the maximum pressure shown on the tire sidewall.

                            But the second point makes sense: "Drive as if you had no brakes."


                            • #15
                              Ya want to get into it?

                              A tiny motor running a energy storage system with a "look ahead" gps system.. a 7hp engine could pull a small car if 7-10hp was stored somehow. In braking, energy lost could be restored to system, climbing a hill? engine would run ahead of time to build to top level power to zoom over it.

                              Honda has went to servo controlled throttle valves.. your foot feed goes to the computer.. the computer tells the car's engine what to do. A simple economy switch could be added to the ecu, and be available for FULL POWER when needed. No more worry ing about the feathering of the throttle.. AND.. why not have "steps corresponding to speed limits".. the computer could accellerate to the proper speed?
                              GO down in 5mph clicks? Pretty soon you'd be able to run around town, all the traffic lights geared to speed limits so you lost less time zooming up to park and wait?
                              Excuse me, I farted.