When accelerating... max efficiency???


bmwboy
09-17-2005, 11:12 PM
I know somebody that can make a car accelerate better than anyone else I know, which means that there is more to acceleration than powershifting within the powerrange (which we are all familiar with)

What has puzzled me for a long time is which method of depressing the gas is the most efficient one... lets assume we stay in the same gear ( to make the example easier) Most people think that pressing the pedal to the metal results in the best acceleration, however its too obvious and everybody does it so it can't be that. One could just gradually depress the gas and get the same result (i think) what seems to be faster than that is depressing the gas about 1/3 then letting go completly, then quickly pressing up to 1/3 and from there gradually press the gas until it reaches the floor 3/3 this seems to be slightly faster than the other two.

Does anybody have any experience, advice or an answer to this?? Does anybody else do something similar???

SiGNAL748
09-17-2005, 11:37 PM
http://img.photobucket.com/albums/v200/Ace$nyper/O-RLY.jpg

The only time I can see this working is if traction was a major issue. Obviously raw acceleration depends on a linear power curve. This "3 stage" throttle idea is pretty much the opposite.

stephenp
09-18-2005, 09:31 PM
carb? or fuel injection? id have to say either way no mash it and go...... if its efi the ecu knows what to do
if its carb there are boosters and crap that take care of that sorta thing....
go get a car at a sales lot and take it for a test drive ... drive until it is warmed up, and approx 10 minutes more to allow all bearings and such to be properly warmed
allow him to drive it and try and find a way to know it isnt just tricking you into feeling something your not.....
ok now drive for approx 10 more minutes and just floor it.... it was faster then right



if that doesnt prove it somebody give this guy a dyno.....

bmwboy
09-18-2005, 10:15 PM
fuel injection... he's not very cooperative in letting u observe what he's doing to achive this effect but he drove a friends car (e30 325) and got it to accelerate faster than the time given in the book and faster than the owner of the 325 (and they took the times together)
I once observed him when drag racing (between friends) with the 325 against a 3.2 L merc. and later against a audi quattro 4.2L , both automatic though so a bad example... the merc lost by far and the audi won repeditly by a half a cars length (same driver in the merc and audi) anyway it was only until 100kmh what was weird was that the 325 tires squeeked 4-5 times until 100... once at start then almost instantly after that, then on the powershift from 1st to 2nd then another 1-2 after that... what is also interesting is that he was accelerating faster than the the 325(e30) with a 525(e34) which has the same engine m20 170hp but is alot heavier this time at higher speeds (however i never saw the engine so i can't be sure) I have a 325 e36 and think I get a slightly better response when I do the described above than when i floor it, yes I loose abit in the begining when I let go shortly, but then it seems to go alot faster, or then again it might be the sudden weight transfer that feels faster...

Gohan Ryu
09-20-2005, 06:59 PM
If it's an automatic tranny just mash and go (adjusting for tire spin).

If it's manual you have to work the clutch - let it slip enough to get to peak torque rpm and keep there by slipping the clutch and working the accelerator - too much accelerator too soon and you'll spin the tires, not enough and you'll drop out of peak torque and you won't pull. That's why some launches feel better than others, and that's why it takes a lot of practice to pull fast and consistent 1/4 mile times.

The fact that he chirped the tires on take off, then the tires broke loose again as it reached peak hp, then chirped again upshifting thru two gears...means he knows how to keep the engine at peak torque and has enough finesse with the clutch to get the power to the ground without spinning the tires.

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