hey... i was wondering if anyone could tell me how tire pressure affects trap speed. when i run, i usually put my tires to about 23-25psi. but is that hurting my top end? its hard to get good traction with anything higher than this. and i've only run an 1/8th... so my 60ft is what really matters. but will having my pressure that low make my 1/4 time worse? i might have a slightly worse 60ft, but will having less resistance on the tires get me a better time...top end? thanks.

 

I doubt lower tire pressure lowers your top trap speed. The main reason you lower you tire pressure is to increase the contact patch to the pavement on take-off. Being that our cars are FWD, the weight on the front end is reduced and the tires contact patch is reduced. On RWD cars, the contact patch is increased because the weight is tranfered to the drive wheels.

 

Once the car is moving past 40mph, I doubt the contact patch on a fwd and rwd car is that much different. In the lower gears is where the car is doing most of the shifting of weight.

As for trap speed, I 've run anywhere from 24-32psi and I've never noticed any measureable difference in 1/8th and 1/4. I'm always aroudn 75-76mph in the 1/8th and 95-96mph in the 1/4. Who says the 4th gen VQ doesn't breath up top?


Dave

 

I've never noticed any difference in trap speeds related to front tire pressure either. Tonight I made two runs at 32psi and two runs at 22 psi the average speeds (of both runs at both pressures) were almost identical.