Please, need advices badly on improving launch in S13

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Vetal
Posts: 374
Joined: Tue Jan 06, 2004 11:41 am

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I found out that there is drag racing forum on this site and thought maybe experienced members might help :)
Problem I have is, no traction whatsoever. I drive fully street S13 with CA18DET and don't plan to turn it into drag-only car. We race mostly at the track where asphalt is 50 years old, very little of asphalt itself remained, mostly small stone chips if you know what I mean. You should probably 700HP 4WD cars spinning all 4 tires to understand how bad it is.
On this tarmac I cannot get better than 2.0' 60ft, 8.05 in 1/8 (did cut 1.8' on concrete old airfield). I want to improve that.

A bit about my setup:
CA18DET, around 360whp (according to 1/4 calculators)
stock weight
lowered a little bit, stock shocks (I think?)
ET Drags (5 years old) in the back, 26x8.5-15", running about 10psi, +/-
I was thinking about different ways to improve launch - different gearboxes, diffs, adding weight in rear, even trying to get custom gearbox shafts fabricated (cause now 1st is useless). Wanted to launch in 2nd gear, too.
I also think my slicks are old now. Which slicks could I fit under S13 wings? Would wider slicks help?

Please watch a couple of my starts so you get the idea :)

http://www.youtube.com/watch?v=iMkLMXXEJTw - you can see how I change early and immediate loose the run
http://www.youtube.com/watch?v=0essyWeFfHw&t=368s - few starts here
http://www.youtube.com/watch?v=0essyWeFfHw&t=483s - few here, good comparison to Alfa with similar power and RWD

I hope I gave main info about my car :) What could you advice to try to improve? I'd like to stay on budget, BTW :)

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Vetal
Posts: 374
Joined: Tue Jan 06, 2004 11:41 am

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Just one more pic :)
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wade001
Posts: 877
Joined: Thu Oct 15, 2009 12:34 pm
Car: 2009 Altima coupe 2.5s mt

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No one will be able to help unless you describe how you launch :facepalm: . tell us and we can try to help :)

Vetal
Posts: 374
Joined: Tue Jan 06, 2004 11:41 am

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wade001 wrote:No one will be able to help unless you describe how you launch :facepalm: . tell us and we can try to help :)
I thought video will tell better :)
I launch from around 6000, release clutch fairly quick (cause you can't really slip that clutch) and let slicks do whatever they can

wade001
Posts: 877
Joined: Thu Oct 15, 2009 12:34 pm
Car: 2009 Altima coupe 2.5s mt

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Video doesnt tell everything. Do you think you are spinning the tires? also i think you mentioned the slicks are old, that would definitely make a difference. The video helps a little but the takeoff seems slow. Are you running a racing clutch. generally, if your dropping the clutch or releasing it too quick you bog down, is that what happens to you? If it is try this next time, I would focus on your clutch release. Bring it to just before engaging, when you go release it a little slower then you do now but feather the throttle to keep the rpms where you want. that will keep a car from bogging/spinning then when you do it right. it will take some practice but I've managed a 2.25 60' on factory all seasons and 135hp at the wheels by experimenting.

Vetal
Posts: 374
Joined: Tue Jan 06, 2004 11:41 am

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You obviously didn't watch the video, did you? :) you can hear that 0.5s after launch I'm hitting rev limiter and stay there until I change :) It's not clutch so it's tires spinning...

wade001
Posts: 877
Joined: Thu Oct 15, 2009 12:34 pm
Car: 2009 Altima coupe 2.5s mt

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I did, but I didnt examin it. If you are spinning get new tires, lower your launch a little, and experiment with the clutch release, and to a longer burnout. that will help you prevent spinning. A vid of my car, didnt spin much, had to drive through the water box, very windy, and was about 35*.http://youtu.be/xUfF_8k5hjY

Vetal
Posts: 374
Joined: Tue Jan 06, 2004 11:41 am

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sound advises :) but I still need some suspension advises at least :)

Vetal
Posts: 374
Joined: Tue Jan 06, 2004 11:41 am

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Also, is VLSD from S14 OK for drag at all?
What's the bigger tire I can fit under S13 wings?

wade001
Posts: 877
Joined: Thu Oct 15, 2009 12:34 pm
Car: 2009 Altima coupe 2.5s mt

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I dont know about what size tire you can run, you can find out by searching. A limited slip differential will help. Suspension wise, soft springs will help the car "squat" back onto the tires, I've heard of people removing the sway bar to improve traction but dont quote me on this as I'm not entirely sure.

Vetal
Posts: 374
Joined: Tue Jan 06, 2004 11:41 am

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Yes that's known trick to remove front sway bar.
Tire size is my main concern now, not very many running drag slicks in S13's...

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meet07
Posts: 1189
Joined: Tue May 08, 2007 5:48 am
Car: 89 180sx rb25det
Location: North Carolina
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Vetal wrote:sound advises :) but I still need some suspension advises at least :)
Vetal wrote:Yes that's known trick to remove front sway bar.
Tire size is my main concern now, not very many running drag slicks in S13's...
Man you sound confused. Stock suspension is best wether you like the 4x4 stance or not. Get anti lag, build boost and launch that thing after a nice burnout( just long enough to see smoke). There isnt much more you can do with a s chassis unless you start fabricating

Vetal
Posts: 374
Joined: Tue Jan 06, 2004 11:41 am

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I've already 4x4-fied my S13 :) all stock springs are back.
Why do you think I need boost at launch if I'm spinning like crazy?


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