Trying to sort out my 98 Z. ATI Procharger kit, with stock manifolds and a cut out. I only made 3 psi. I have since added headers and a full magnaflow catback. I have the P1SC kit. I want 5 psi. Stock motor with racetronix fuel and 42#inj. I want 5 psi, and would like to see 450 hp. Been in contact with the supplier, and will be pulling the head unit tomorrow or monday to determine current size. The tuner that got me where I am thinks the pulley is to big (I think it is a 4.25 or 4.5.....). Looking to see what size some others are running with P1SC head unit..... Only other mods I am considering at this point are valve springs and MAYBE some rocker arms.....

Anyone? What size?

 

It's hard to tell what size pulley you have without looking at it or measuring it. If you get the serial number off the head unit, call ATI. They can tell you what size it was when they shipped it.

 

That may be the problem. I bought the unit from a supplier, and got a D1SC unit with a 6 rib pulley. Returned the D and got shipped my P (I know I know....I should have kept it and kept my mouth shut...). Got the P1SC, and it had a 8 rib pulley on it. Sent the pulley back, and got the 6 rib that was on the D. I will put money on the D1SC with the 6 rib would have made 5-6psi, and this 8 rib is too big...

Blah blah blah....I will have to try that