3.33" to 3.12" pulley
 

I have a 3.33" pulley and changing to a 3.12" do I need a smaller belt? If so, what size?

The tensioner should take care of it but what size belt do you have right now?

^+1 sounds like the tensioner would do it, but if its loose, id go 1" smaller... you could probably get away with 2" but it may be reeeal tight to get on.

not related to your question, but how much boost were you seeing with the 3.33" pulley?

10 PSI.

Must be nice..I am only seeing 7ish PSI

what else do you have done to your car?

7PSI at 370rwhp is pretty damn efficient.

Its intercooled with a powerpipe so I could see me gettin like 8 lbs, but when it was dynoed the highest the tuner said he saw was 6.8 lbs. Everything else on the motor is stock, which is why I figured I would have a higher psi if anything due to all the restrictiosn. I have an o/r h pipe and a catback which may free up the flow a little, but not that much.

that's crazy, because I'm running the T-trim (technically E trim (the V2 version (helical cut gears))) and a 3.4" pulley and running 16PSI and I can go all the way down to a 3.12 pulley and still going to 7000RPM without overspinning the blower, which I figured would be around 20 PSI


So you seeing only 7PSI is insane.

What year is your car again? I think cliffy K said that the 02+ cars had a little bit more agressive cam specs, which could explain loosing some through the exhaust valves.

IDK though, that's a tricky idea

What size is your pulley?