Just got done putting a D1sc twin highflow kit (kit was bought 100% new from Exotic Performance Plus) on my 93 z28 M6. I have noticed that there is a grinding noise coming from the head unit when i am letting out the clutch to get the car moving from a dead stop. People have told me these blowers will have a small "marbeling" sound, and I hear it at idle. But for some reason when i give a little gas and let the clutch out, the noise gets louder from about 1200 rpm to 1500 rpm, then it goes away. I cant hear it when changing other gears, only when from a dead stop. Any ideas? Is this typical?

 

Check and make sure you have enough clearance between the blower and the ABS bracket. Different engine loads could be making it bump up against it causing your grinding noise.

 

Could be...I will have to get under there after work and see if it is touching that bracket. They are 12 rib pullies, and there werent any interference issues with the fan shroud when I installed it, but i will take another look at that too. Judging by the small marbeling sound that can be heard with my blower at idle and every other procharger i have seen, it seems that that noise becomes amplified once the car starts moving from a dead stop

 

I got a chance to get in there and check, and it appears to be less than an 1/8" of clearance from the head unit and abs bracket. I will get under the hood tonight and create more clearance. Thanks!