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-   -   first launch on slicks. (http://www.njfboa.org/forums/showthread.php?t=12161)

84HOtransam 08-05-2005 03:22 PM

first launch on slicks.
 
its just a 305..not much power..infront of a 9in and 27x10.5 hoosiers qtps...how much pressure should i run at the track?

Fasterthanyou 08-05-2005 04:48 PM

http://hotrod.com/techarticles/43059/
Do a couple burn-outs to find an acceptable starting point. I'd probably start with 20psi and go from there. With the 305, if you can't do much of a burn-out on the street with the slicks than don't worry so much about the tire pressure. Just do a small water box burnout to get the water off, stage, and put the pedal to the floor.
What kind of power are you making at the engine?

Jersey_TA 08-05-2005 05:18 PM

Your not going to have to worry about spinning. I had 20 psi in my 26x9.50s when I went 11.93. You should be good with a higher psi without any problems

84HOtransam 08-06-2005 12:44 AM

its an L69 with headers/exhaust...thats all..the car ran a best of 14.5@95 before the rear and suspension...

i started at 11psi and just left it...i launched at 4000rpm and 4 of my friends said i pulled the front wheels.. i really need more power...

Batman 08-06-2005 06:22 AM

Yup you really need more power. Probably launches like a beast then falls over right? I'd do 18-20 PSI and ditch trying to yank the wheels, if it is a standard ride the clutch out so the engine doesn't bog, if it is an auto roll into the throttle. Your 60' times will be worse but the 1/4 will be faster.

84HOtransam 08-06-2005 10:23 AM

Quote:

Originally Posted by Batman
Yup you really need more power. Probably launches like a beast then falls over right? I'd do 18-20 PSI and ditch trying to yank the wheels, if it is a standard ride the clutch out so the engine doesn't bog, if it is an auto roll into the throttle. Your 60' times will be worse but the 1/4 will be faster.

yea it stumbled a little after the intial launch on that run... i still need to practice with it..

Fasterthanyou 08-06-2005 11:56 AM

11psi, that's lower than I would do. The higher the pressure the more stable it is at higher speeds and the lower the rolling resistance (free power). That's why you want to run the most pressure you can get away with, not the least.
As for bogging, I would never roll into the throttle with a 14 second car with slicks. You shouldn't need too and if it bogs it's a carb tuning issue that should be resolved. Rolling into the throttle is for traction issues... I doubt a 14 second car is going to have a tuff time with traction on slicks at the track. I could be wrong though, just saying...
NJSpeeder would know better than me. I hope he chims in and gives you some tips. His car was a 14.2 with slicks. I believe he would just punch it off the line with the L03 (edelbrock heads TBI).
On a side note, nice times for a L69 with just exhaust work. 95mph is doing really well for an old 190hp 305. Is your car gutted?

Squirrel 08-06-2005 12:05 PM

what kind of 60's were you cutting?

NJSPEEDER 08-06-2005 12:31 PM

with a 305 on that size tire i would start around 30psi. with my 91 on 26x9.5 QTP's i could run consistantly at 27psi in any weather on any track condition.

later
tim

jrsfast84 08-06-2005 03:43 PM

were your friends watching you from behind the car or from the stands, if they were behind you, how much did your rim sink to the track, i would put 25 -30 psi, to start with, just so your not spinning the tires off the line.good luck.

84HOtransam 08-06-2005 04:11 PM

Quote:

Originally Posted by Squirrel
what kind of 60's were you cutting?

1.9's

the car isnt gutted...i removed the spare tire and my tool bag from the trunk..everything else is still in there..

Tru2Chevy 08-08-2005 09:54 AM

I would also say to pump the slicks up to the 26-28psi range and see how you do there. You'll be faster across the board that way....

- Justin

foff667 08-08-2005 10:03 AM

I would say start at 30 psi and do a decent burnout...you should have no need to go lower then 20psi at your current power level though.

Slow Z 08-10-2005 11:28 AM

I hit 1.70's so far on my QTP's:

Hooks at the track with 20psi and thats about what I drive around on the street with. On an unprepped surface (ie the street) I gotta bring it down to about 16psi or I'll spin pretty bad. The car is dead smooth on 20psi but 15psi it gets wobbly sometimes especially during shifts.


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