What is the best method (if any) for drag racing with an auto tranny??

When staging the car in the lights hold the brake with your left foot and bring the rpm's up to the stall speed of the converter. When its time to launch remove your foot from the brake and floor the gas. Let the tranny shift on its own from the drive position as it will do it better than most people can manually

My drinking team has a racing problem!!

Make sure OD is off -- that will ensure your transmission is locked the entire time it is in third gear (less power lost through the transmission). I do not believe ECT makes a difference in shift points from 1-2 or 2-3 (it does for the 3-4 shift though), but it certainly doesn't hurt to have it on...

Jeff Gore
87t hardtop
11psi and 3050lbs

Sometimes a line lock is the only way to go... my auto has a stall of 2400, yet my turbos dont spool till nearer 3000 making it impossible to get a decent takeoff. If i fit a line lock i can then rev just past the stall point and if timed correctly get an awesome takeoff.

at least thats the plan

adi
1992 original JDM JZA70 2.5tt 'Limited' - Decat, hybrid turbos.




http://www.jzasupra.com

What's a line lock, and how do you do it?

A line lock is a hyd. check valve that holds the pressure in your brake lines untill you release it. Same as holding the brake with your foot. Line locks are handy for heating up your tires if you have one on the front brake only, allowing the rears to spin freely in the water box. A tranny lock is the way to go in an automatic.

My drinking team has a racing problem!!

I'd only fit one to the fronts and hopefully this would enable me to get past the stall point and launch without too much wheelspin (after a bit of practice).

Whats a tranny lock? similar to a brake line lock?

adi
1992 original JDM JZA70 2.5tt 'Limited' - Decat, hybrid turbos.




http://www.jzasupra.com

I don't think you can launch on the fronts only, I think the motor would push the car past the staging lights. You would have to have all four brakes on your line lock for staging.

My drinking team has a racing problem!!

I've heard of many line locks being fitted to fronts only and achieving great results on a launch. I cant see it pushing the car forward.

also, fitting a line lock to the rears as well will surely give me the same result as sitting there with my foot on the brakes anyway? Ie i *still* wont be able to get past the stall rate of the box.. hence spool up will be after i release the brakes. Hopefully fitting the line lock to the fronts only will enable a 'slight' amount of play between spin and launch.

adi
1992 original JDM JZA70 2.5tt 'Limited' - Decat, hybrid turbos.




http://www.jzasupra.com

I have seen cars with all four brakes locked push themselves off the line when pre-loading the drivetrain for a launch. I am sure that with front brakes only, the motor will slide the front tires right out of the staging beams; giving you a red light. A front brake only line lock is for the waterbox only. Most drag cars use a two stage or "two step" line lock. The single stage is fronts only and is used in the waterbox. The dual stage is for launching and locks all four brakes. The trick is that the four way lock is controlled with selenoids and all you have to do is hold one foot on the gas and then click a little hand held button to release the brakes. This makes for wheel standing launches and fast reaction times.

My drinking team has a racing problem!!

I guess the only way is to try it.. after all a front brake line lcok system is fairly cheap so no loss really.. if it doesnt work it doesnt work. Im not really interested in major dragging, its just gonna be fitted to enable me to get a better launch at the local timed quarter.

I see what youre saying but i cant see how im going to get past the stall rate without letting the rears have even a small amount of freeplay.. this is, after all, what happens with a power brake launch.

adi
1992 original JDM JZA70 2.5tt 'Limited' - Decat, hybrid turbos.




http://www.jzasupra.com

Try it, I would like to see if it works out. I hope it does work well. I have not seen a Supra with a line lock yet, but I have seen many other turbo cars with it. They really don't get the stall speed up any higher but they do get to build up some boost before launch. Good luck and keep us posted.

My drinking team has a racing problem!!

A line lock is for use in the water, not on the starting line. The way to leave under boost is to install a converter that is designed for your application.

http://www.importperformancetrans.com

I've heard that the A342E can have a relatively simple upgrade to raise the stall converter to 2900 rather than 2400.

anyone know any info?

adi
1992 original JDM JZA70 2.5tt 'Limited' - Decat, hybrid turbos.




http://www.jzasupra.com

A converter upgrade is relatively simple, it involves removing the trans and replacing the converter. The Devil is in the details, however. You must make sure to get your T.C. from a shop that will customize one for YOUR particular application (ie one that will work with the modifications that are done to your car). This will insure that you didn't waste your money. Any reputable shop will also offer one free stall adjustment, in other words, if within a year of purchase, you change stuff in your motor the converter can be altered free.

http://www.importperformancetrans.com

The ECT button changes the shift points of 1-2-3, not 3-4. With an automatic, you need a transbrake, not a line lock. You need a massive engine with degraded(drag only) brake system to move a car with the brakes planted and the engine floored.

In Tressel we trust.

I find it very hard to believe that someone has created a Toyota transbrake without me knowing about it! Unless of course you are refering to using a domestic trans in a Supra.

http://www.importperformancetrans.com

How much does your shop charge for a high stall torque? Just like a generic 3200 stall.

quote:

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I find it very hard to believe that someone has created a Toyota transbrake without me knowing about it

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I guess you dont know everything.
I didnt say I know where to get one. I was just explaining for the masses. A trans brake, well if you dont know how a planetary gearset works, this isnt the place, holds the car by not applying a clutch pack, or by holding output, or something similar. With an electronic control unit in charge of the A340E, it cant be that hard anyway. Better get an external cooler.

In Tressel we trust.

Actually, I am relatively certain that I know how a trans brake works, I have been building automatic transmissions for fifteen years, and have built many units with trans brakes for cars running as fast as the seven's. A transbrake operates by simultaniously locking the transmission in reverse and forward and upon the release of reverse through the use of an electronic solenoid the vehicle launches. A transbrake doesn't yet exist for a Toyota unit, I actually know this because I am in the proceess of attempting to develop one. If you are sure that you know how easy it is to make one, perhaps you would like to share that information with the rest of the world, I'm sure that you could sell them.

http://www.importperformancetrans.com