Ok So Buddy of mine ran at the track only had 3 psi in his driver side tire(long story on how that happened) and nearly 18psi in the other, His 60ft was a 2.2 but his 1\4 was a 15.4@87 now we were expecting much better with his car, How much would that tire pressure effect his highend?

 

3psi in a tire will DEFINATLY slow you down.

 

with 3 psi i'd imagine the floppy mass of rubber would cause some drag at high speeds.

 

Push a car with overinflated tires. Push a car with very deflated tires. The increased rolling resistance takes more power to overcome. The front tires on my drag car are at 40 psi.