Launch Tips for Drag Racing- 1/4 mile

[SilverStreak]

You're gonna smell clutch when launching this way. Like brake pads, it's a part that was made to wear out...

[Greg S]

hey SILVERSTREAK, what times have you run in your CL and 330 as of now?

[SilverStreak]

CL-S, 14.11 at 95.9 mph
ZHP, 14.008 at 97.49 mph

[Mrsideways]

:

Wanna get humbled? Run your mouth before ever having been to the strip about how you expect a 14.2 time, especially since you have a CAI and chip in a 95 M3.

Then go out and run a 15.1 on your first run, never getting better than a 14.4.

That oughta do the trick...

Here's humbled..... Put a Big Honkin V-8 in a volvo wagon. Spend $5K building the motor. Run out of money and get stuck with a little Throttle body and some home Brew headers and an open dif. Talk smack about expecting to run 12's maybe 11's. Spin the piss out of the tires all night long with the automatic tranny and run a 14.6 as your best run.
Fix the throttle body, Heads and Dif issue, put a Manual tranny in, buy a set of drag radials and watch the car burn in a parking lot because of a faulty alternator without ever going back to the drag strip. I might have it running again in a few weeks, we'll see.

[SilverStreak]

Some recent questions via PM:

Q: I took my MC to the track. Terrible run. 13.2@111mph, my best time. My best trap was 112@13.5 . People are telling me that I can reach low 11s. Well I need your help in doing so.

I threw on tyres the same day that I went to the track. I origionally had 265s but went wider with 275s. My 1st run was with street pressure 40psi. I bogged the launch, BUT 1st gear held all the way through. The moment I threw it into 2nd all hell broke loose. My 2nd run I did it at 35psi, worse run of all. By the time I hit the 1/8 I shut it down because I couldn't get traction. My 3rd run I did it at 30psi and I launched hard. 1st was nonexhistant, 2nd was $hit and 3 held.

My 60' were averaging 2.2 . I'm running now Falken 451 with a traction of AA. Before I was running Kuhmo Extas with a 265. Those with a stock flywheel was hitting 2.0 60' like it was nothing. Now I would be lucky to hit 2.0 60' with my LTW.

People are telling me to go with a psi of 22 and below. Some even told me to go wit a tyre pressure of 17. I don't know but I can try.

After that night I'm to the point of throwing on a set of drag radials. Oh BTW when I left the track I inflated my tyre pressure back to 40psi. Went on the TPK and threw it into 3rd. Punched it at 2500 and by the time I hit 5500-5700 the ASC came one. Yea 85 and I break the tyres loose. Hopefully I'll be able to post the vid tonight.

So if you've got any advice you could lend me I would greatly appreciate it.



A: With traps of 111-112 mph, I'd guestimate low 12's are possible, not low 11's.

What you need is 275/40-17 BFG Drag Radials with all that power.

And probably start with 25 psi in the rears, 55 psi up front (less rolling resistance), and tweak from there.

Are you riding the clutch at launch and on upshifts?

With my s/c'd Z3, I could never let the clutch out fully on upshifts at the strip, I had to stab the throttle like 50-75% and then gradually but quickly squeeze it to the floor, and my left foot was on the clutch, not fully out halfway thru 2nd, and part way thru 3rd.

Heck, I once got sideways on the 3-4 upshift at 93 mph at the strip.








Q: Truth is I don't ride my clutch, nor do I dump it. Leaving the light I don't break the tyres loose. Its when boost comes in with peak Tq, thats when the tyres breal loose. During my up shifts I don't ease the clutch, I make em quick. Thats probably why I break the tyres loose from 1st to 2nd .

So you are saying to start off at 25psi on my street tyres, ok I'll do that. I'll also go easier on the up shifts.

I also raced a friend of mine with a Supra Turbo who traps 118s . When him and I were together, when we both had traction, I was pulling from him even after the up shifts. So would you say low 11s would then be possible?



A: The only way to get better ET's is to minimize traction loss, which = riding the clutch.

As far as traps and ET's, it depends on the 60' times involved.

My Z3 trapped at 115-116 mph, and ET's were 11.7's. But my 60' times were 1.6x. That was on DR's.

On street tires, my 60' times were more like 1.9-2.0, and my traps went up to 117-118 mph. But my ET's were more like 12.2-12.3...

Traction = lower ET's, but can eat into your traps as well cuz traction = friction.

My buddy has a lightly modded Z06, cuts 1.7x 60 times, and he runs 11.7's at 118 mph.

Those are good 60' times, so it depends on your friend's 60' times as it relates to his traps and ET's...

Know what I mean?












Q: This info that you gave me in reguards to traction = lower ETs, but possibly lower traps is priceless. Great info. I'll try it out and see at the track tonight.

I also spoke with another friend. He told me to stay out of the water box when I do my burn outs. Just to do a dry, clean-off, burn-out, then to stage and launch.




A: Yes, on street tires or drag radials, generally go around the water box.

For pure slicks, and low end torque-monster V8's, the water box is helpful to do a burnout without launching all over the place or breaking a seal somewhere...

[BMoW]

Silverstreak-
I don't undersand, in the first post you mentioned that wheel spin in between shifts is bad because you loose time. I can understand that because the car is slipping and not gripping and going. But, If one were to double clutch or just plain old shift slowly (relatively), so that one wouldn't loose traction, wouldn't that in turn take more time away that shifting as fast as possible thus resulting in an overall greater time?

[SilverStreak]

Silverstreak-
I don't undersand, in the first post you mentioned that wheel spin in between shifts is bad because you loose time. I can understand that because the car is slipping and not gripping and going. But, If one were to double clutch or just plain old shift slowly (relatively), so that one wouldn't loose traction, wouldn't that in turn take more time away that shifting as fast as possible thus resulting in an overall greater time?

yes, it would, that's why you shift fast and crisp, and utilize the clutch to modulate what makes it to the ground on each upshift, just like you do at launch...

That's what I was explaining about with throttle stabs on upshifts...

[Dark Helmet]

ehhh, double-clutching=nono in drag-racing.

[mazenz]

doesnt double clutching only apply to downshifting? and only with non syncromesh trannies? whats going on here?

[MrBlonde]

You NEVER double clutch on upshifts at drag racing. You slam it in fast and modulate with your clutch as Dave has said.

[confuZion3]

I hope that I didn't miss this somewhere in this thread, but if I did, then I guess it won't hurt. For you first timers, you may scare yourself a bit at the end of the night when you realize that your clutch is slipping after a few runs. If you are launching the way that silver describes (probably the best way!) then you are going to heat up your clutch really quick! If you make a run really hard like that, I would not recommend getting right back in line again to go a second or third time. You should let your clutch cool down a bit so that you can get the most out of it on the next run. Heated clutches tend to slip a little bit. They are JUST LIKE BRAKES. Brakes fade from high heat, so do clutches. Don't worry though. If you experience these symptoms, just let the car cool for a few minutes. They will go away, provided that you let the clutch cool down. I usually open my hood after each run to let everything cool. Also, speaking of cool: try running your heater on full blast to take away some of the engine's heat while you're running. Hotter engines don't perform as well as cool ones.

Hope that this little tidbit helps, and that I haven't repeated anyone else here. Happy raceing!

[Raphy]

How do you shift into first. Do u let the clutch out like you would normally shift into first from a stop sign, or do you let it rub for a quick instant and then pop it? How bad is it for your clutch, and if done wrong, can something just break?!

[SilverStreak]

How do you shift into first. Do u let the clutch out like you would normally shift into first from a stop sign, or do you let it rub for a quick instant and then pop it? How bad is it for your clutch, and if done wrong, can something just break?!

Shift into 1st? At the strip? Huh? I'm not sure I understand the question....?

[fzust]

Along the same vein....
I had my best ET of 13.42 @105.8mph in my 95 M3 with 320RWHP turbo in 100+ temps. I have stiff springs in the HR sports with bils. My wheels are lightweigh SSRs 18x8s with 245/35R18 Dunlop race tires rear w/ about 26psi tried higher seems to make no difference. 245/35R18 GY f1gsd3s on the front pushing 55psi. I also have UUC sways. Basically great stuff for the street, not so great for the strip.

This 13.42 with a 2.15 60' was never duplicated. I did a string of 13.6s several with better 60' as low as 2.05. I realize the problem is that once I get on the power I am spinning in 1st and second. I need to work on sillver streaks clutch riding even more.
Here are the questions:

BFG makes a 275/35R18 DR. I *think* it can be made to fit. Is this low profile tire going to help me any? Would I be better off with some 16" wheels and ET streets? Any recommended 16" wheels?

How much are the HR Sport springs killing me? Should I go to a more stock spring rate or softer? Any recommendations? I am upgrading the Turbo to about 450RWHP. Any guestimates if that will get me into the 11s on DRs?

Thanks to SilverStreak and Mr. Blonde for previous help!

[scottycs]

Even with those temps your trap seems really low, my NA 3.2 has trapped in the 104s.

[SilverStreak]

Along the same vein....
I had my best ET of 13.42 @105.8mph in my 95 M3 with 320RWHP turbo in 100+ temps. I have stiff springs in the HR sports with bils. My wheels are lightweigh SSRs 18x8s with 245/35R18 Dunlop race tires rear w/ about 26psi tried higher seems to make no difference. 245/35R18 GY f1gsd3s on the front pushing 55psi. I also have UUC sways. Basically great stuff for the street, not so great for the strip.

This 13.42 with a 2.15 60' was never duplicated. I did a string of 13.6s several with better 60' as low as 2.05. I realize the problem is that once I get on the power I am spinning in 1st and second. I need to work on sillver streaks clutch riding even more.
Here are the questions:

BFG makes a 275/35R18 DR. I *think* it can be made to fit. Is this low profile tire going to help me any? Would I be better off with some 16" wheels and ET streets? Any recommended 16" wheels?

How much are the HR Sport springs killing me? Should I go to a more stock spring rate or softer? Any recommendations? I am upgrading the Turbo to about 450RWHP. Any guestimates if that will get me into the 11s on DRs?

Thanks to SilverStreak and Mr. Blonde for previous help!

Don't get a 275/35-18 DR's, too low profile, no sidewall flex. Go with the 275/40-17 DR's...

[fzust]

Any recommendations on wheels to hold those and fit an E36 M3?

[SilverStreak]

Any recommendations on wheels to hold those and fit an E36 M3?

Lightweight 17x9's... like SSR's...

[AlaskaBlue]

I just went to the strip for the first time today. I had lots of fun. Thanks for the tips on launches. Mine were terrible. Wheel spin all first gear. My best was a 16.2.

My question was about suspension. I have KW variant 3s. When I go to the strip should I lower the rebound and compresion in the back and raise it in the front?

[SilverStreak]

Softer all around on a street car running 15-16's should be fine...

[JBgotM]

Well, I got a good deal on a set of barely used BFG DRs and should work even though they aren't optimal size. They are 205/40/17s and yes, I know they are thin. My hope is that they are stickier than street tires of normal size. The smaller tire will also alter my gearing somewhat and should pick up some time.

Normally when I go to the strip, I just have all-season 255/40/17. I also will be starting to raise up the rear end as far as possible (i have coilovers) to get the negative camber out (normally have about 3 degrees). Last time I went I was spinning through first, most of second and chirping in third getting a 14.0 @ 102 with a 2.2 60'.

Dave - a couple questions for you...

1.) wouldn't you actually want the smallest tire that provided enough grip for a good launch? example... a miata doens't need the big/wide tires that a 454 would need. It would simply add rotational mass actually causing you to be slower.

2.) Do you think the 205/40/17 DRs will be a decent tire for my power and car?

3.) I saw you mention to pull around the waterbox if you have street or DR but to go through it with slicks. Is it because the DRs have tread? Aren't they still a similar compound that would benefit from the water if you got it out of the tread?

TIA

[rsagona1]

I wish I had read this before I went to the track a few months ago. Ran 14.2 @97MPH in my stock m3 it was my first time at the track with it. I was launching like shi*, I just revved it up to 3 and dropped the clutch (that's all I knew how to do at the time, I know how to slip it out now). My 60' I don't think were that good, like 2.3 maybe. Plus I had bald tires, I think now that I know how to drive and shift faster, and launch better, I can hit 13's next time.

Thanks for the tutorial.

[SilverStreak]

Well, I got a good deal on a set of barely used BFG DRs and should work even though they aren't optimal size. They are 205/40/17s and yes, I know they are thin. My hope is that they are stickier than street tires of normal size. The smaller tire will also alter my gearing somewhat and should pick up some time.

Normally when I go to the strip, I just have all-season 255/40/17. I also will be starting to raise up the rear end as far as possible (i have coilovers) to get the negative camber out (normally have about 3 degrees). Last time I went I was spinning through first, most of second and chirping in third getting a 14.0 @ 102 with a 2.2 60'.

Dave - a couple questions for you...

1.) wouldn't you actually want the smallest tire that provided enough grip for a good launch? example... a miata doens't need the big/wide tires that a 454 would need. It would simply add rotational mass actually causing you to be slower.

2.) Do you think the 205/40/17 DRs will be a decent tire for my power and car?

3.) I saw you mention to pull around the waterbox if you have street or DR but to go through it with slicks. Is it because the DRs have tread? Aren't they still a similar compound that would benefit from the water if you got it out of the tread?

TIA

1. Not really. You want width, and you want sidewall flex. But yes, for the sake of gearing, you don't want to throw a 26" tire where a 25" tire belongs, etc. It all depends on your launch and traction. In the Z3, I used 275/40-17's which were taller overall than the stock 245/40-17's. But I was getting rubber on the 3-4 shift at 93 mph...

2. Only one to find out, give them a shot. I'm betting they are too small, too narrow, and the sidewall is too small. I'd go 245/45-17's or if you can fit them 275/40-17's in the BFG DR's...

3. DR's are sticky radials/steet tires. You can do a quick burnout to clean them off. But heating them up too much won't be worth the lost clutch life, especially with a car with under 300 rwhp. You'll launch well with them just by cleaning them off.

[SilverStreak]

I wish I had read this before I went to the track a few months ago. Ran 14.2 @97MPH in my stock m3 it was my first time at the track with it. I was launching like shi*, I just revved it up to 3 and dropped the clutch (that's all I knew how to do at the time, I know how to slip it out now). My 60' I don't think were that good, like 2.3 maybe. Plus I had bald tires, I think now that I know how to drive and shift faster, and launch better, I can hit 13's next time.

Thanks for the tutorial.

Cool, that's what this thread is here for. Practice the new technique a few times, get comfy with it, develop a feel for when it's about to break, etc...

[rsagona1]

Cool, that's what this thread is here for. Practice the new technique a few times, get comfy with it, develop a feel for when it's about to break, etc...

I went out to the track again, but wasn't expecting to do well since my clutch is almost gone. You know it's going bad when you don't chirp anymore, and the revs stay the same going into 2nd and 3rd gear then slowly drop back down. Funny thing is I still managed to pull off a 14.4 @95mph with a 60' of 2.0. My off the line was great but once I got rolling, my gears wouldn't grip; the RPM's wouldn't go down. And what pisses me off is the minute I get off the track, the clutch doesn't slip anymore If you were in the passenger seat you'd think the car was a 20 second car, it's very deceiving with this clutch. I just managed to pull off a decent 1/4 time because of my 60'. But anyway the next time I go to the track I'll have a Kevlar clutch and lightweight flywheel.