Thread: Rattling Supercharger

My supercharger rattles but only when its under boost, even just a little boost. I have heard everyone say "coupler" when it rattles at idle, havent heard anything about under boost. Also, doesnt seem as if it makes much power while under boost. Two spark plugs have come out smashed in 6 months. I think possibly the Catalytic converter is partially pluggeg and causing all this? Any help or advice would be greatly appreciated.



-2003 GTP, all bone stock, EVERYTHING
-Original motor was blown up, people didnt change oil. They also ran 87 octane.
-Used motor claims 90k, from junkyard, swapped superchargers because coupler was real bad on other one.

Thank you both for your replies.
My problem is, I dont want to spend money/time on a new shortblock if I dont know what killed this one. If it is the Cat, then I would like to know that conclusively. Dont want this present issue to kill future motor.
With the entire car being stock it seems like the options would be limited as to what could cause the pistons to be "chipping"

Clogged cat makes sense. Either that your engine knocked from the start and the 3" downpipe will help you with that.

But when knocking is occuring, you have higher cylinder temps which results in post above.

Originally Posted by Bio248

knocking doesnt usually chip pistons do tell you the truth, heat does. when the top ring gap closes because the cylinders are too hot then it pops off a piece of the piston, always in the same spot on every motor.

Bio, about the chipping of the piston. Would you expect a sound that ticks only can be heard starting at 1000 RPMS stopping at 1500 RPMS could be the piston or the ring? I let my brother-in-law, listen to it. He works at CAR MAX as a master mechanic. I trust him, just wondering if you have come across that same sound. Does not get loader as RPMS increase, goes OFF at 1500 RPMS and higher. Could that still be a lifter or what do you think?

So, the supercharger rattling noise is definitely the coupler? Even though it never rattles at idle and ONLY under boost?

If this coupler is rattling under boost would it make sense that it is far less efficient when rattling?

my gtp rattles so i changed the coupler. it still sounds like rocks rattling around. any suggestions?

Originally Posted by bluevet03

my gtp rattles so i changed the coupler. it still sounds like rocks rattling around. any suggestions?

bad bearings or low on s/c oil?

Originally Posted by Bio248

a ticking could be a number of things. its best to narrow it down to one area before trying to decide what it is. lifters usually dont go bad unless theyve got a lot of miles on them, though.

Bio thanks for the quick reply. It is at 159,000 miles.

I also replaced the nose drive.