This is a vortech T trim.. I was trying to find a bigger crank pulley but was unsuccesful at finding one at anywhere near a decent price. So I decided to go with a smaller blower pulley but the one im running now is a 2.75 and im seeing 10psi sometimes 11. I dont believe the belt is slipping but it is a possibility (anyway to check?). I was thinking Im going to go with a 2.65 or 2.55 blower pulley. I dont know if slippage will be an issue though.. whats the smallest you all have used? Know of anyone selling a 7" crank pulley?

 

Look for rubber on the head unit. I was using a 7.2 that I had machined with a 3.12 on my v2 with no slip, I did use a belt condtioner when I first broke the belt in. Vortec no longer makes a 7, I bought one used hard to come by. Not sure if anything bigger than a 7.2 will work not much room under there.

Makes more sense to increase crank pulley than decrease blower if trying to avoid belt slip.

John

 

any other ways of checking for belt slip??

 

What are you trying to accomplish?

On my LS1, I run:
8.00 Vortech base kit crank setup
2.85 Vortech blower pulley
Custom manual tensioner

I saw 17 on the dyno, but had some slippage and bracket flexxing issues. so I was only seeing 14-15 psi at the track with the YS.

I added a strut brace so I hope for some new big numbers and less belt problems.

 

asp makes (or at least used to make) a 8" 8-rib crank pulley. i was using that along with a 2.95 blower pulley and had no slipping problems at all @ 17-18psi on a t-trim. you have to grind the blower belt tensioner some and re-position the fans slightly forward/upward if you are using stock fans to clear the 8" pulley. i wouldnt go any smaller than where you are at on your blower pulley unless you go to a 10-rib setup

 

I'm running a 6 1/2" crank pulley and recently upgraded to a 2.65" blower pulley. I'm getting 12 pounds and when it slips I can feel the car kind of bucking or falling on it's face for a split second. It's hard to explain, but when the belt slips under boost you feel it and sometimes you can smell it. I have always been able to solve the problem by re-tensioning the belt, but if it slipped bad it should be replaced as the belts can glaze over from the heat.
BTW I'm running a p600b with an 8 rib setup.

 

Whats your compression ratio for that 17psi of yours.. lol.. mines 8.5:1.. Im gradually upping the boost...