vcept

Hi, after reading some of RoRo's posts, i was tempted to go out there and race my 2IS against my friend's s2000. Well in every case I win but i was wondering if there are any good techniques out there to prepare me for harder cars. For example..how do you launch at a specific RPM on an AUTO car? I've had people told me to hold the break and gas at the same time..but that just makes my break squeal like crazy or maybe rev it in N and pull it down to DRIVE when you launch? Any help would be appreciated!!!

al503

Holding the brakes and accelerator down at the same time is called brake torqueing. This allows the engine to get it's rpms' higher at a standstill where it's producing more power. You'll have to experiment and see if there is an optimal rpm to let off the brakes.

Reving the engine in neutral and then putting it in drive is not adviseable. This is called the 'neutral slam' and is just about the worst thing you could do to the tranny unless the car has a safeguard for this built in. Not sure the IS has this safeguard but I won't be the first to try and find out.

vcept

Will doing the brake torque screw up my brakes in the process?

al503

It shouldn't hurt the brakes. However, you should try to avoid brake torqueing for more than a second or so. The shorter you do it, the better.

tt061880

The best launch for me is at idle and get on it, no brake torque or anything. This is after 4 visits to the drag strips and brake torque the car really didn't do anything for me but created more spins.

javyLSU

iTrader: (21)

I got slightly better numbers at the track when I brake-torqued to around 2500 RPM. Both combfilter and I noticed a drop in our 60 ft times the more we experimented with the RPM's. While brake torquing is definitely not good for your car, please, please, DON'T neutral slam your car - that'll cost you a new transmission.

Javier

Javier

lobuxracer

iTrader: (2)

The service manual says do not brake torque for more than 5 seconds. Doing this heats up the transmission fluid extremely quickly, and can cause damage to the transmission in very short order.

Toyota is not known for building strong transmissions. I never brake torque more than about 2 seconds. Just long enough to get the rpm up to about 2k, then release the brake to go. The rpm you use will depend entirely on the surface you are on. A well prepared surface and clean tires will allow more rpm. On the street, don't expect to be able to rev as high and not spin excessively - or have TRAC and VSC kick in to spoil the fun straight away.

Julez

Any reason why my VDIM light(not the chime) always goes on when I launch my car? Does it take a second or two to grip the road?

Soda

I've ran my S and my IS a few times and both cars are close. The IS is faster, DEF more torque, but it's not like the S is in your rearview...but if you get the S on any kind of twisty road, the IS is done. It can't outhandle the S2k. Sloppy!

caymandive

iTrader: (2)

I agree with this 100% Each and every time I just launched from Idle I got my best times. Maybe it has something to do with the temps being lower, but trying to brake torque only leads to wheel spin. I would imagine at warmer temps 80+ there may be some benefit to brake torque as the tires will hook up better with less spin.

al503

Controlled wheelspin is actually a good thing for a couple of reasons:
1. Maximum traction (or braking) is achieved with the tires slipping about ~15%.
2. Torque braking allows the engine rpms to be higher at launch, where it's producing more torque/power. IE: the engine may be making just 20-30 bhp right off idle.

Now, getting just the right amount of spin is where the tricky part comes into play. If the drag racers that do this for a living can't get it right all the time...

lobuxracer

iTrader: (2)

Exactly. Add to this that surface preparation makes ALL the difference in the world. If you're following a major event and they've put down a lot of VHT and rubber, you're going to get a lot more grip than if the surface has been cleaned and is not prepped. There's also the issue of tire temp, and while it usually doesn't help to heat up street tires, there are times when you may have collected a load of rock on the return road that you would want to scuff off the tire before launching.

It all comes down to knowing the surface you are on, the traction available from your tires, and the ideal rpm to launch given those parameters.

Gernby

iTrader: (1)

I've had poor success with torque braking. Now that it is getting colder, my car and tires have 10K miles on them ... if I get any wheel spin started in 1st, it will continue all the way to 2nd. Torque braking just makes that problem so much worse, that it will shift into 2nd too soon.

homer4598

Yeah, I would definitely advise against the "neutral slam" method. My brother did that to his car when we were younger. Rev'ed it to 3500 RPMs or so, then slammed it into drive. Big clunking sound, drive shaft rolls out from under the car. It was hilarious (well, not so much to him).

Hutch27

I remember those days but the only difference was I rev'ed it to 7500 then slammed to "D". I remember doing that to my civic quite often and the transmission handled it just fine. As a matter of fact it engaged quite smoothly while you can see the smoke coming from the passengers side. I think the VDIM has alot to do with why the "slam method" cause damage to the transmission.

I also remember my friend that owned an automatic supra that easily put 600 rwhp playing around with both style of burning out never had problems with the transmission. I beleive that completely disabling the traction control or VDIM would put less stress on the trany in any hard driving condition.