i have a 99lightning and i recently put a 6lb pulley on it and now im getting some noise from it while im idleing in gear is when it is worse. the truck has 24000 miles on it it sounds like its bearing noise you can even feel it in the intake but you cant feel anything in the blower or the snout what is my problem?? is this cavitation? is their a fix

 

I assume that this pulley makes the supercharger spin faster right? If so, your Blower is trying to force more than it needs into the cylinders at idle. You are hearing the air trying to get past the valves and it makes that fluttering noise. If you ever heard a big rig with straight pipes at idel you will hear the high pitched whistle of the exhaust turbine in the turbo charger. Except that whistle isn't smooth like a jet engine whistle. Its the exhaust gases being pulsed one at a time from the cylinders past the turbine. That makes that fluttering whistle. Perfectly normal.

 

This is not normal I would take it to your local tuner cause if you got a 6# lower on it I assume that you have a tune to get the a/f right. Well see what he says. Sounds to me like a bearing but if you cant feel it in the blower I dont know. I wouldn't drive it much.

 

I have read of similar noises caused by rotor cavitation from overdriving the blower with a 6lb pulley. In those instances it did not hurt anything. Pull the belt and check that the blower spins smoothly. If it does I would not worry about it.

 

with the belt off it is smooth i took the boost by pass back factory it seems to have queiting the noise down some

 

if it started as soon as you installed the pulley it is most likely not a bearing .there is a vacum activated valve on the back of the supercharger and if you pull the lever on most stock trucks it makes a bad bearing sound and you can feel a rough vibration . i don;t know how to fix your problem , but you do need to put it on a dyno to set you a/f mixture

 

i have a superchip that is close so they say but their are no local dyno shops and no one close that flashes superchips..

 

smog shops have the ability to read a/f mixtures . try and talk to a smog tech and see if he can help you !

 

yea they do but i have no smog shops in alabama.... cars here do not have to pass emissions.

 

Any shop with a good analyzer should be able to do an emissions check. A performance shop with a dyno too would be better, though.