yep the blower isn't turning as much as it should thus causing lost power.

 

The other bad part about using a U/D pulley on the crank for a FI car is that even if you DO get a smaller pulley for the blower, you will be loosing surface area on the blower pulley, so it will be more prone to slip.

Aka, even if you repully the blower to keep the output the same it will tend to slip more. If your running signficant amounts of boost this can lead to a loss in PSI and belt shredding.

 

Are you sure he has underdrive pulleys and not a s/c upper pulley? With s/c'd cars, the smaller the s/c upper pulley is the more boost they create... may want to double check with him, see which pulley he has.

 

well he had the UDP's on there for a couple of years and just this past month got the blower.....i asked him if he took the UDPs off and went back to stock and he said he didnt need to, that it was working just fine....then again, maybe he doesnt know the inns and outs.....so yes he is running the blower and udp's.....

lol his loss i guess