Launching the FWD

[FastFWD]

What is a good rpm to launch with on my '91 Eclipse GS-T? Nobody around here seems to really know. I am running '98 stock GSX 17" wheels.

[ProjectGSX]

I do not have a FWD, but drag racing them has always interested me so I have talked to quite a few people about it. The one thing everyone agrees on is that it is hard, and just about every car is going to have a different RPM point.

So the best thing to do is get out on the track and see what feels good to you. I would say start around 3,000RPMS and then experiment going higher and lower. Wheel spin is not your friend.

Also, play with the air pressure in your tires. Try running 15-20 psi in the front. The tires will sag and give you better traction.

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-Brian
Project GSX
http://www.projectgsx.com/

[Quadcylla]

Okay now were're talking :). Launching a FWD is more tricky then an AWD IMHO. I take it your car is stock? And stock tires? Well then somewhere around the 3000 rpm mark or just above is where you want to start from. Then when you go you have to keep your rpms up enough and slip the clutch out easy enough to not have the car bog once rolling BUT not so much that you squeal your tires. It takes some time on these turbo'd FWD to find that sweet spot where you can harness the turbo off the line without slipping. Look at your 60ft times on every time slip you get... if your getting 2.3s in stock form then be happy... not many can do much better. The effect you are looking for is to see your nose rise up at launch and not come down. If it comes down then you bogged... but don't squeal or your launch will suffer.

I've found that reducing the front tires to about 18 psi is best and pump the rear ones up to 45~50 psi.

Have fun... it's a constant battle everytime to hit that sweet spot.

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http://geocities.com/r337m0nk3y/dvv/asthanos.gif Quadcylla
92 Laser RS-T FWD

[FastFWD]

It's basically stock, I have a K&N filter with the housing removed, boosted it up to 15psi of boost and just installed an upper intercooler piping kit with the 2G throttle body elbow. Lowered with H&R sport springs. I didn't think about letting some air out of the tires, that would eliminate some of the wheel hop I experience sometimes.

So far my best run was 15.3 @ 92mph, I know, slow, that was without the UIC pipe, maybe that will make a difference this Friday when we have a test n tune.

Off the subject, anyone recommend a specific exhaust I should get? I want to go 3".

[greenstreak]

It took me a while to get the launch down on my fwd Talon. I am running Nitto NT-450s sized at 235/45 and aired down to 20psi. My best results (2.2 60') come from launching at 3300 rps and slipping the clutch while applying a good amount of gas. I would need to slip the clutch through about 70% of the first gear to get good times without major wheelspin. This is on a mostly stock car with an ACT 2600lb clutch with the street disc. It takes alot of practice, I have about 25 runs in now. This is with driving around the water box and not doing anykind of burnout. Hope this helps.

[Steve Rennick]

I must agree with Mike (Quadzilla) here....definately by dropping the tire pressure you will notice a difference, and with a FWD, you need every little bit of help that you can get to pull decent 60 ft times.

[FastFWD]

So, in order to really get a good time, the 60 foot time is important? No one had ever explained that to me. I know one guy at the track said I was losing 4 tenths of a second because of my 60' time, but I really didn't understand what he meant.

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John Lewis
1991 Eclipse GS Turbo

[Quadcylla]

Yup. Let's say you slip one run and get a 60 ft of 2.7 seconds as oposed to your best of 2.3. Assuming the run is exactly the same after you hook up then your E/T will be off by .4 seconds from your best run.

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http://geocities.com/r337m0nk3y/dvv/asthanos.gif Quadcylla
92 Laser RS-T FWD

[dsm4eva]

I've always been quoted an old drag rule-of-thumb that a decrease of a tenth within the 60' will net a decrease of a .15 on the overall ET, not just a 1 for 1 decrease.

[ChosunDSM]

dsm4eva, that rule of thumb is pretty close to reality.

[RS_Guy]

So what are best 60ft times you FWD people are getting?

My best time ever is a 2.311 at 37psi on my Pirelli P7000s. No burnout...

Believe it or not, my 60ft times seemed to get worse at around 26psi....

My suspension is completely stock, and I didn't use my strut bar. I heard that the strut bar seems to help with front end stability on the launch. I will use it next time.

So please share with us your times and techniques.

My main problem still is wheelspin though. If I give the car full-throttle after launching carefully I can still spin the tires :-(

[dsm4eva]

Best 60' Times:

<UL TYPE=SQUARE>
<LI> Street tires - Dunlop SP8000 - 2.280
<LI> Street tires/lightened interior - 2.200
<LI> Nitto 555Rs - 1.995
</UL>

[$upraMan]

It took me a few tries. I think this was my 5th or 6th run but I've had the car for 2 years, just never been to the strip before:

60'.......2.303
330'......
1/8.......9.532
MPH.......73.91
1000......12.335
1/4.......14.693
MPH.......98.07

My next run had 2.215 60' time, but the car was heatsoaked so I ran 14.735 @ 96.09.

That was done w/ stock '98 GS-T with K&N on stock tires @28 psi front, 40 rear. Spare tire in and everything :). Launch at ~3600 RPM and slip the clutch.

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Drew
98 GS-T
95 TT

[FastFWD]

Okay, now a dumb question, here is how my timeslip reads, what does it all mean?

reaction: .632
I1 : 2.333
I2 : 6.447
I3 : 9.866
MPH (I3): 4.563
I4 : 12.831

E.T. : 15.306
MPH : 91.306

I understand most of it, just the "I"'s that confuse me.

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http://www.geocities.com/sm4474/anirei.gif John Lewis
1991 Eclipse GS Turbo

[$upraMan]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by FastFWD:
Okay, now a dumb question, here is how my timeslip reads, what does it all mean?

reaction: .632
I1 : 2.333
I2 : 6.447
I3 : 9.866
MPH (I3): 4.563
I4 : 12.831

E.T. : 15.306
MPH : 91.306

I understand most of it, just the "I"'s that confuse me.

<HR></BLOCKQUOTE>
That's a pretty weird time slip. I can only guess that I1 is 60', I2 is 330', I3 is 1/8 mi, and I4 is 1000'. Your reaction time is how quickly you react to the green light. 0.500 is perfect, so you did pretty good. And reaction time does not affect the end result as far as time/speed, but it does, of course, when you race someone.


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Drew
98 GS-T
95 TT

[greenstreak]

I have seen timeslips from a few different tracks and I have never seen the I's before. I think Supraman is right though.

[TSi92]

I have about 100 runs on my car, and I still can't get it to launch right!

Here's what can I say on how to launch the car:
Get some desent tires, not the goodyear GT II's that I have :D
low the pressure to around 20 psi
keep the revs at 3500 rpm's
slip the clutch untill around 5500 rpm's but don't go WOT yet
Go WOT at around 6500 and shift to second at redline.

That's what I usually do and I usually do 2.4's but I think that my tires just plain suck so that's why I can't get any better. I got a 2.3 once but I missed second! arrhh! oh well..

Here's why FWD DSM's can't get a nice 60ft. It's because that damn open front diff!

[TSi92]

I have about 100 runs on my car, and I still can't get it to launch right!

Here's what can I say on how to launch the car:
Get some desent tires, not the goodyear GT II's that I have :D
low the pressure to around 20 psi
keep the revs at 3500 rpm's
slip the clutch untill around 5500 rpm's but don't go WOT yet
Go WOT at around 6500 and shift to second at redline.

That's what I usually do and I usually do 2.4's but I think that my tires just plain suck so that's why I can't get any better. I got a 2.3 once but I missed second! arrhh! oh well..

Here's why FWD DSM's can't get a nice 60ft. It's because that damn open front diff!