Specific Noise Occurance

metalman

Registered User
I've read many other noise discussions, but nothing seems to match mine.

I just got my car running after being down for 2.5 years. I am hearing a fast pulsing sandpapery high-pitched noise specifically at 2800 rpms, ONLY under load. Not in park/neutral. I didn't run the noise too long 'cause I don't want to damage anything. I heard it two times I pushed it over 2800 and let off quickly.

Car was down from a supercharder malfunction-loose front bearings caused case scoring. Magnum Power replaced rotors with the abradable coated rotors, new rear bearings, fixed case.

Could it be harmonic resonance from a small exhaust leak? I hope not valve chatter, I don't know.
 
The noise you are describing sounds like a bad bearing on a belt pulley, and it only happening under load leads me to think it would be on the supercharger side. Try taking the crank to jackshaft belt off and zip-tie the bypass valve open, and take the car for a ride and see if it still does it.
 
I'll give it a shot, but how would load affect the noise coming from a pulley bearing. If its spinning at 2800 rpms, it spinning a 2800 rpms with or without load....no?

I can try recording the noise too. Maybe this weekend, but my wife might be having our baby, so we'll see. :)
 
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