Launching for drags w Steptronic

K

k3nny

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#1
i have a steptronic e46, like most other ppls...and i was just wondering, if i was @ the track or planning to drag, how do i launch?

i have a friend w an auto car and he pulls the handbrake up while accelerating a tad bit and lets it go when its time to go however i tried that and the handbrake cant seem to hold my bmw down even with minimal acceleration...to actually get the car to not move while slightly accelerating, i would have to pull the handbrake REAL REAL hard and i was afraid i might damage the handbrake mechanism..snap a cable or seomthing.

and if i have my foot on the brake pedal, and let it go and floored the accelerator pedal, there would be a slight delay in response in regards to power delivery on the cars part...are our cars equipped w drive by wire? my car is 1 month old..

any suggestions?

thanksss a whole bunch guys in advance
 
frolf

frolf

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#2
don't to brake stands, just throw her in DS and mash the throttle, thats the best way to safely laucnh, if you wanted to light 'em up you probably should've gone with a manual, either way have fun [thumb]
 
Kirby

Kirby

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At SCCA autoX runs, I do what Black330 says - 2K RPM for about a second and release the brake, floor it at the same time. It's probably a risk, but I think a small one that I'm willing to live with.

Definitely turn off DSC for drag racing. Turn off braking control (hold DSC button for 5 seconds until BRAKE light comes on) for AutoX events.
 
jrt67ss350

jrt67ss350

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I agree with Black330 and Kirby. You tend to get the strongest launch with an automatic by holding the brake and applying enough gas to get the revs up to about 2000 rpm, then release the brake and floor it at the same time. This technique essentially tries to emulate a transbrake, which is a device added on to automatic trannys that all true drag racers use to launch their automatics quickly. This permits the engine to basically be running closer to its torque peak at launch, and at about the rpm that the torque convertor is doing a large amount of torque multiplication.

However, if you get a lot of wheelspin doing this (which you probably won't in a BMW), then you are revving too high or applying full throttle too quickly - it all depends on various factors related to the car. If I do this in my Camaro, it'll light the tires up, but it's a low-end torque monster, unlike a BMW.

I will also say that, while a emulating a transbrake is the quickest way to launch an automatic (a real transbrake is the fastest way to launch an auto), it is hard on the transmission and other drivetrain parts. Don't do it constantly if you don't want to be replacing expensive drivetrain parts - BMW's are not drag cars, especially 318's.
 
Kirby

Kirby

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Bimmerlife said:
Get a F****** Dragster if you want to do drag race. Not a $30000 BMW. What a dumba$$.
Click to expand...
People drag race $2000 Hondas, $100,000 Pro Stocks and $1 Million top fuelers. Why exclude a BMW just because it costs $30,000? [fake]


He also mentioned TRACK in his post. Many people track their $30,000 BMWs and he asked a very legitimate question if he intends to track his car.
 
N

NZL

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I'm curious as to why people would be so strongly against using the brake for a short period in conjunction with light throttle.

The brakes & engine should act independantly, wouldn't the car should just think its pulling a really heavy load or up a very steep hill with a sumo wrestler behind the wheel.

How does this damage the transmission?[hihi]
 
K

k3nny

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#16
Bimmerlife: i bought this car.

i do what the f*ck i want with it. you buy your car, you do what the f*ck you want with it.

i wont tell you what NOT or what TO Do.

I posted seeking advice and experience. not ppl telling me to buy another car.

editted by moderators
 
K

k3nny

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#19
fair enough...i understand yr reasoning but possibly word it in a better way.

i would've bought a 330ci or M3 with a stick or SMG if i could afford it but i paid AUD70,000 for this car just 1 month ago and were i living in the US, i could've bought me 2 330ci's.

many people drag many cars for many reasons. many people buy many different cars for many different reasons.

i bought a bmw not to baby it and work for it as opposed to it work for me.
i was asking abt how to launch cause i was planning to go down to my local plex and give it a shot and see what i'd get in the quartermile, not set a record!

in all eventuality, all i seek was advice. Advice on how to use my car and not someone telling me off on how i choose to use my car.

the bmw transmission is strong. although with minor problems, i would say very strong and up to the task of me changing 500rpm's before redline for less than 30 seconds.. drag racing isnt as bad as it seems in a car and i would think tracking it would put more stress(correct me if im wrong)

with tracking, you frequently cycle thru gears and frequently use the brakes to extremely hot levels.

with drags, you just accelerate and change. dont go past e red line or stay 500rpms below and i think it shdnt be that bad... and u get space @ e end to slowly brake and slow down before turning around.

tracking also places more stress on the various parts of the car with the g forces associated with hard cornering oil starvation in the engine...sumps and all that..

just wanted to know abt launching cause i used to drive a R33 Nissan Skyline and this is more of a different thing
 
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