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HOW DO YA LAUNCH A DRAG RADIAL STICK CAR???
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LAYDRAG
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Joined: 23 May 2006
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Location: GA.
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PostPosted: Wed May 24, 2006 11:02 pm    Post subject: HOW DO YA LAUNCH A DRAG RADIAL STICK CAR??? Reply with quote

Well, not afraid to ask and admit, my drag racing knowledge is limited. The good news is I'm a fast learner. SO HOW DO YOU LAUNCH A DRAG RADIAL STICK CAR? My 'ol 77 vette with a 406 and T56 is about to learn some new tricks. The tires are new NITTO 555 EXTREME drags 285 35 18. My first gear is a 2.97 with a 3.55 rear. Overall is a 10.54 to 1 i think, pretty darn close to a Z06's gearing. I wanna get a good 60 foot time, are there tricks for the IRS cars to get them to hook? I know the mustangs have a problem. One last thing the car has "vette brakes" dual mount transverse glass spring that is adjustable rate 325 350 375 and 400lbs. Currently on 375. Any help greatly appreciated, thanks in advance.
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jonny_b
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1979 Chevrolet Camaro

PostPosted: Fri May 26, 2006 12:02 pm    Post subject: Reply with quote

Let me see if I understand the question(s)...Are you saying that you are having troubles getting the car to hookup?

If so, you could lower the rear spring rate and create more weight transfer.

Play with tire pressure, and be sure that your burnout is long enough to get those drag radials sticky..

I noticed you have 18 inch wheels. How much side wall do you have on those drag radials?? that could be part of the problem too, not enough contact patch...

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Aerosmith
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PostPosted: Fri May 26, 2006 12:51 pm    Post subject: Reply with quote

You haven't had the Nitto's at the track yet have you? I have the Nitto's and I find that after the initial first heat cycle (burnout) that you don't need too much burnout to get them sticky. I run mine at 12psi and heat them until I just see smoke then roll out. Anymore than that and they got greasy and had to cool pretty long to get good again. I've never run a stick car with DR's so I can't answer to that but I can relate my experience with that tire. Smoke has Nitto's too I think, maybe he can give his experience.
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SMOKEmUP
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1979 Chevrolet Camaro

PostPosted: Fri May 26, 2006 1:46 pm    Post subject: Reply with quote

I run Nitto's as well but with an auto.

Basically I do the same as Aerosmith described but I run a little more pressure, 14psi.
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LAYDRAG
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PostPosted: Fri May 26, 2006 6:57 pm    Post subject: Reply with quote

Thanks for the help guys, I just got the nittos and havent been to the track yet. With the old tires i had a problem with wheel hop. What i wanna know is technique. Anybody got any tips or hints on how to launch this car effectively, read "FAST 60 FOOT" RPMs? how far out do ya slip the clutch? I hear its an art to get these type cars to hook. I thought about softening the rear spring to help transfer. Another thing 12 psi? I took mine to 15 and they looked flat. Seems to me that would create some killer rolling resistance and hurt the trap speed, is it safe to run'em that low at 110 mph?
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Aerosmith
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PostPosted: Fri May 26, 2006 9:46 pm    Post subject: Reply with quote

My car is 3630 lbs with me in it, and with 12psi in them they hardly bulge. I started at 15psi and went down in 1/2 lb increments until I stopped gaining.
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240Z8
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PostPosted: Sat May 27, 2006 4:16 pm    Post subject: Reply with quote

I figured GrandSportC3 would be all over this one, he's hitting some nice 60s. I'm sure drag spring rates for the irs will be different than your typical solid axle setup. I know from the standpoint of the early 240/60/80Z irs you don't want to get the rear soft, but have really firm springs otherwise you waste time squatting=slower e.t. instead of forward motion. Too soft a rear puts a severe angle on the 1/2 shafts causing breakage or excessive wheel hop. The most successful sub 10 second Zs, sub 1.5-1.3 60s, use a soft front strut setting, sometimes with the front sway disconnected to allow weight transfer and a stiff rear spring to eliminate all the monkey motion of the rear irs soaking up the power. As far as tire pressures, does anyone else notice the lower pressures get kind of squirmy on the big end of the track? I could feel it when I got around 18 psi. Maybe this was due to my relatively narrow 225s?
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Aerosmith
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PostPosted: Sat May 27, 2006 9:32 pm    Post subject: Reply with quote

So far my traps are only 110, but I don't notice any looseness.
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cutlass389
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PostPosted: Sun May 28, 2006 11:21 pm    Post subject: squimy Reply with quote

Hey 240, I've been running a 24.5-8.5x15 slick and when I get to 15psi and lower (at 3150 lbs w/me) I notice my a$$ end is squirming all over the place at the big end. Subsequently I'm running 16 psi w/ my solid axle and air bag setup. My 60' are in the 1.74-1.79 range from idle.
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Aerosmith
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PostPosted: Mon May 29, 2006 2:14 am    Post subject: Reply with quote

You're running full slicks or dr's cutlass389? I'm on Nitto dr's.
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cutlass389
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PostPosted: Mon May 29, 2006 10:37 pm    Post subject: M&H Reply with quote

It's a M&H full slick w/out tubes on 7" wheels, Aero. I only run 1/8mi so traps aren't that high(85mph). This is my first experience with slicks so maybe what I feel is excessive is actually normal.
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Aerosmith
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PostPosted: Tue May 30, 2006 7:10 am    Post subject: Reply with quote

I haven't had my full slicks on yet so I can only go on what people say and what I remember about bias ply tires back in the day.
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GrandSportC3
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1968 Chevrolet Corvette

PostPosted: Wed May 31, 2006 8:49 am    Post subject: Reply with quote

If you are serious about drag racing, here's how you'll get your car to hook:

1) Front suspension:

Get the 213 lbs/inch Moroso Trick front springs. You'll need to cut about 2 coils of the spring to get the correct ride height. The spring rate with 2 coils less is about 250 lbs/inch.
Get Competition Engineering adjustable front shocks and set them to 90/10. Part number CEE-2610. You can also use some bump stops and have the front sitting on the bump stops on launch. When coming down, the bump stops are hit before the spring compresses too much to reduce bouncing in front.. (from the rebound)

2) Rear suspension:

You already have the stiff spring, so you could get the QA1 adjustable rear shocks. Set them to about 6 - 7 clicks as baseline and adjust from there based on success.
In addition, fabricate some bump stops to limit rear end travel to about 1 inch or so. This might not be needed but is helpful. All the big time Vette racers use them.

I personally don't use the bump stops front and rear and I get a little of a bounce.. At one point, I'll have to install them...

Tire pressure: Start with about 26 lbs of air and make a pass.. If you spin, drop the pressure by 2 lbs and try again. Repeat that until you get your best traction or until you hit 18 lbs of air.. Do not run less than 18 lbs of air in Drag Radials!!!

The cost of the entire suspension setup breaks down as follows: (approx. numbers)

Front springs: $100
Front shocks: $80 ($40 each)
Rear shocks: $300 ($150 each)
Bump stops: $50 for front and rear:

Total suspension upgrade cost: $530


Last edited by GrandSportC3 on Wed May 31, 2006 12:08 pm; edited 2 times in total
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Aerosmith
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PostPosted: Wed May 31, 2006 11:55 am    Post subject: Reply with quote

That's interesting about the tire pressure. When I got my DR's I asked around alot and got your 18 psi as a high starting point and 12 psi as a minimum. Is your 18 psi based on what you have experienced or did you get it from a manufacturer? I theorize that like street tires, race tire pressure would vary with the weight of the car and/or the load each indiviual tire had to carry..ie: my Beetle uses 24 psi in the front, my truck 45 psi front. I looked at Nitto's web site and could find nothing about DR pressures, but BFG said:

Run no less than 12 pounds of pressure in BFGoodrich® g-Force T/A® and Comp T/A® drag radials for maximum traction at the strip.

I'd like to hear from more people who are frequent DR users about what they run. In the mean time, if I make it to test n tune tomorrow, I'll try the 18+ psi and see how it compares to what I have been running.
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GrandSportC3
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1968 Chevrolet Corvette

PostPosted: Wed May 31, 2006 12:05 pm    Post subject: Reply with quote

Aerosmith wrote:
That's interesting about the tire pressure. When I got my DR's I asked around alot and got your 18 psi as a high starting point and 12 psi as a minimum. Is your 18 psi based on what you have experienced or did you get it from a manufacturer? I theorize that like street tires, race tire pressure would vary with the weight of the car and/or the load each indiviual tire had to carry..ie: my Beetle uses 24 psi in the front, my truck 45 psi front. I looked at Nitto's web site and could find nothing about DR pressures, but BFG said:

Run no less than 12 pounds of pressure in BFGoodrich® g-Force T/A® and Comp T/A® drag radials for maximum traction at the strip.

I'd like to hear from more people who are frequent DR users about what they run. In the mean time, if I make it to test n tune tomorrow, I'll try the 18+ psi and see how it compares to what I have been running.

The taller the sidewall, the lower pressure you can go.. All the Corvette Drag Racers on 18 inch wheels don't go below 18 pounds of pressure.. With 15 inch tires you can go a lot lower.

I used to run BFG Drag Radials (275/60R15) and I got best traction with about 18 pounds of pressure... (1.591 60' time with my old 383)
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