Lauch control ? Jumpstart ? Healhy for the TC, gearbox ?

[SzymekCRX]

Hi

I've been wondering whether performing a jumpstart eg. holding the brake pedal and throttle doesn't harm th TC or gearbox.

I'm afraid of using this technique. Should I ?

I heard that RPMs are limited while holding the brake pedal simultanously with throttle.

I suppose many of You use this launch control procedure but I wanted to approach from the engineering point of view :)

[speedtrapped]

This topic has been discussed, duck rat duck foot method?....Any brake boosting puts enormous strain on your TC and i would guess gearbox. If your TQ is stock, and u have a high mileage gearbox, if u make habit of launching, I would assume you wont have the trans or TQ for very long.

[SzymekCRX]

Yeah, sorry :)

http://www.rs6.com/showthread.php/23094-how-do-you-drive-an-automatic-and-other-new-owner-thoughts?highlight=duck+foot

[speedtrapped]

dont be sorry...I have done the technique a couple of times, its intoxicating.

[ben916]

dont be sorry...I have done the technique a couple of times, its intoxicating.

I'm gonna need proof of that... video proof...

[speedtrapped]

oh right, well I need a passenger....Ron is closest to me. My schedule has been royally fcked last 2 months. After Christmas.

[Amar]

Get a warranty and launch away to your hearts content, I too am scared to use this technique.

[kilian tuning]

how many seconds (part of) will that differ from 0-60?

[kilian tuning]

is it possible to get a seperate warranty on the box...?

[Amar]

I very much doubt that, the only way I can see the box alone being covered and not the rest of the car is if it were rebuilt/replaced.

[speedtrapped]

^^^^ what Amar said, and if u can properly launch, a sec can be saved

[speedtrapped]

sorry, not accurate, but 3.6 sec, can be achieved

[kilian tuning]

we dont have to worry about the box when going manual...wow, think about that, launch control all the time..

[Bigglezworth]

Racers have used this technique for years and there are thousands and thousands of cars that use it without any problems whatsoever. My Turbo Buick stalls out at 3800-4000rpm using a high stall non-lock-up convertor which makes it launch like a bat out of hell and pull the front wheels off the gound with slicks on the back. Neither the engine, tranny, driveshaft, differential, or axles are stock though...

Clearly not something required for your family sedan. What you need to best understand however is that the car is only as strong as the weekest link and as many others have already mentioned, a 'stock' tranny w/ stock convertor will likely fail eventually under strain. There is no predetermined formula or timing for it, but I can guarantee you it will happen when you lease desire. Now, if you opt to utilize a modified tranny with improved clutch packs, improved lubrtication, improved valve body, and a higher stall modified convertor, then you could do this day in and day out without fail. In fact you could then look at using a transbrake too and really push the limits of launching.

My tune can hold revs over 2K prior to the hydraulics starting to engage the gears and then it goes like a bat out of hell. You won't save a second like some think, but you certainly can gain a few 10ths of a sec depending on your tune and coupled with weather/traction conditions.


Here's pics of what you DON'T want happening.....
120541205312052

[ttboost]

I've been 4.0 0-60. I've also personally changed my TC, so I keep my 0-60's to a minimum...

[kismetcapitan]

can't remember what model, but I seem to recall a certain GM 4-speed automatic that is popular among drag racers. With a manual transmission and lots of power, you need a multiplate clutch. And it is HARD to get those launches just right, especially with big turbos that will lag horribly if the RPMs drop. There's a technique with Skylines where you hold the car with the handbrake and then every so slightly engage the clutch to load the drivetrain and take out any slack, all while keeping RPMs way up. Brake boosting sounds very appealing for launching.

[ttboost]

Brake boosting is the way to go for killer launches, but remember, when your brake boosting, your cooking your TQ and trans fluid at the same time.

[Elevens]

To Hell with Brake Boosting !! Ripping every body up off the Light or Terrorizing every one on the Highway is good enough for Me. These Transmissions are to expensive to be messing around with..........................

[speedtrapped]

^^^^^ so true.....better to get a stage 1 flash, and your car will feel like 2 extra rockets were attached, no need to BB