I just installed an Alta 15% pulley (along with the shorter belt and tensioner stop that comes with the kit) on my 05 MCS. I made sure the belt was aligned, the pulley was bottomed out on the SC shaft and that the belt was routed accordingly around the crank, a/c, alternator etc.

The first thing I noticed when I drove it was a whining noise coming from the belt area. I originally thought that was due to the pulley spinning the SC faster but it is a completely separate sound. You can clearly distinguish this noise from that of the SC. It comes from the belt area, not the drivers side where you I normally get the SC whine from the Alta intake I also have.

The noise is not present when idling. It becomes noticeable at about 2.5k rpm and gets louder as the rpms increase. I've looked under the hood while the car is running and the belt and pulleys all appear to be running fine. I never heard this sound before I installed the pulley. This is EXACTLY the sound I am getting:


Any ideas guys? I'm stumped

 

Did you use a goodyear gatorback belt? If so those damn things are loud.

 

Nope its a napa belt! This guy here

http://www.altaperformance.com/hardt...er-pulley-belt

 

hrmm, something must not line up brother. Or some debris on another pulley.

 

Look to see if the alta tennsioner stop is vibrating....some early ones made lots of noise...later ones were a bit better.....
Also look at the belt/pullies....check for oil, or a shiney spot on thr belt or any white inducating where it is rubbing....

 

Pulley and CAI does make the supercharger wine lodly.

 

If it's making belt noise something is not lined up. Recheck your pulley install if it's on correct I'd be concerned that the shaft moved on the supercharger when you were pulling the pulley. If that happens the supercharger has to be rebuilt.

 

Yikes. Hopefully it turns out to be something simple! If it was a supercharger related issue would the performance not be affected? It pulls hard (noticeably more so now with the pulley) but I'm scared to drive the thing. I'll check out the tensioner stop. I also get a slight rattle around idle........maybe I didn't tighten the tensioner stop enough and its moving around? But could that also cause the whine/buzz sound I'm getting? I'm pretty sure I tightened it down but who knows at this point