Knock from blower after breaking belt

[epracmetcon]

So I thought I'd try a gates rpm belt on my 2.9 Whipple since I was getting some dust on the pulley. Put it on, had it tensioned around 50% and broke it pretty quick. Limped the car home, stuck a new belt on it and now it sounds like there's an angry gnome inside the blower beating it with a hammer. Take the belt off and noise goes away. Spins free by and without any resistance. Anyone ever encountered this before? The one thing that concerns me is I did limp it home about a mile and cylinder head temps did get a touch on the high side, but as I said, take the belt off, noise goes away.

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[MrOldschool45]

Hey there! Sorry to hear about that. I won't be much help, but I was curious about your setup. Is it just a Stage 2 with a 3.750 or 3.625 pulley on 91/ 93? Or, are you on 3.5" or less pulley and pushing some high HP #s? If it's the earlier, it seems strange that you're breaking belts. I'm wondering if your 50% tension is an issue. Per Whipple instructions, it should be set to 75-80%. I hope you figure it all out.

Take Care,

 

[bluestang50]

If you have an old school flat head screw driver put your hand around the base of the grip and put it to your ear. You can put the flat head side on different areas of the supercharger to better tell where the sound is coming from.

This guy shows you what I mean.

 

[epracmetcon]

Hey there! Sorry to hear about that. I won't be much help, but I was curious about your setup. Is it just a Stage 2 with a 3.750 or 3.625 pulley on 91/ 93? Or, are you on 3.5" or less pulley and pushing some high HP #s? If it's the earlier, it seems strange that you're breaking belts. I'm wondering if your 50% tension is an issue. Per Whipple instructions, it should be set to 75-80%. I hope you figure it all out.

Take Care,

3.625 pulley on 93. It was an RPM belt which has less stretch so they need to be tensioned less. I spun in 2nd and it tickled the rev limiter which is when it broke.

If you have an old school flat head screw driver put your hand around the base of the grip and put it to your ear. You can put the flat head side on different areas of the supercharger to better tell where the sound is coming from.

This guy shows you what I mean.

I took a stethoscope to it and the noise was coming from what sounded like the inside of the blower. Whipple suspected possibly the tensioner but the noise is no longer present.

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