Hello. We just got back from our local track and we were a little disapointed on our time. Car is a 92 civic couple weighs 2050 with driver on a 23x8x15 slick. I am curious what u guys launch your cars at rpm wise? Tire pressures?? We need a starting point. My turbo car cuts 1.60's all night But with this all motor car we can barly get 1.90's. Type r trans also. Just need some input.

 

Car went 13.44 at 100mph

 

what engine, how much hp tq is engine making, cams, intake manifold, what wheels are you using? judging by mph, car is making enough power to cut 1.8 easy. i would say around 6000-7000 rpm launch should be good, first pass of the day i would put tires at 12-13 psi and after burnout tires should go up to about 14psi, if tires spin on launch drop pressure immediately after pass a pound or two depending on how bad it spins and try again. my allmotor setup b20vtec type r cams making 200-205whp 22x8x13, 12-14 psi, 6500-7000 launch prelodading would cut 1.7 60ft's all day everyday in a ek hatch full weight minus rear and passenger seats and a/c system(still kept heat). also judging by your mph it looks like it would be good to go to 13" wheel with 22x8x13 tire.

 

I agree, start with 12-13psi. Its going to differ on every setup. But here's the story on mine.
On my all motor car we had to have the tire pressure around 10-12psi to get a little spin so it wouldn't bog down. Any less and the tires would grab too hard and bog down the car. 1.9s every time. I was making around 260hp out of a B series. There is probably a better way of doing this, but what we did is, first day out it was cold. We had the tire pressure around 7-8psi. Kept getting 1.8 60' launching at 5000. We just raised the launch until we got the wheel spin we wanted and ended up cutting a 1.6 60' @ 7000rpms. Then the next race it was a lot warmer. Kept the same launch and tire pressure, but kept bogging hitting 1.9 - 2.0 60'. So we left the launch at 7000 and raised the tire pressure. We ended up at 10 or 11psi and got the 60' back down to 1.6.
So it all depends on temperature, power and launch rpm. Unfortunately there is no better way to figure out what is going to work best for you than Testing.
And one other point, on my all motor V6 car, I kept getting 1.6 60' all day. After some seat time and getting the launch just right, we did a 1.5 60'. What made the difference was a real good Preload. If I just dropped the clutch it would blow the tires off. But without making any changes to tire pressure and rpm launch, that good preload made a world of difference.

 

Thanks for the responses guy's. Hopefully next week we can play with tire pressures again. The setup is ls bottom 81.5mm RS machine p30's. B16 head old crower stage 2 cams blox manifold with 70mm t body and ANR street sweeper header with 3in bumper dumper. E85 with bosch 630's tuned on crome by me. Butt dyno guesses 180ish hp.