I have had underdrive pullies for quite awhile and no issues. Recently bought a vortech supercharger kit so I had to change the water pump and crank pulley back to stock. Got a new belt and tensioner. Have no issue cruising but when at wot There is a very bad vibration. So I figured the belt was too tight since it was a bit of a pain to get on. Bought a 1/2 inch bigger belt and the vibration is gone. But now with a quick rev or wot the belt squels because it is not tight enough. I don't know what to do now. Any thoughts?

 

You could try getting a slightly larger idler pulley. Or shim out the alternator with washers.

Tanner

 

So I spaced out the alternator a little bit.., but I'm almost positive that the noise is coming from the alternator pulley., is there a way to test if the bearing is bad? I don't have any charging issues

 

Take the belt off and spin the alternator with a drill somehow? Maybe use the old pantyhose trick and use a pair to make a short belt on the alt pulley and then to your drill and spin it up?

Come to think of it, you could do the same for the tensioner and maybe idler, smog and a/c too jut so see?

 

I'd love to know how much that supercharger cost?