Can cats rattle at high rpms?

[ryan101]

I think one of my cats it rattling when my rpms get to abot 3500 or above that, i think it's the cats because it sounds like it comes from near the gear box on the passager side, sounds like it's under the seat! It's like a vibrating sound it's pritty loud, sounds like it's in the car, I had a look in the car but nothen is loose!

 

[noddycommodore]

They easiest way to check if your cats rattling is to jack up the p/s of the car and give your a firm wack with a soft hammer or your hand. If it rattles it's stuffed and that's your problem if not there is a heat shield on top of the cat that's bolted to the floor that may also be your problem

 

[SirNemesis]

Of course they can rattle. If it is a loose component in the exhaust it can rattle at any RPM. My money would be on the cats, might be time to invest in a couple of nice hi-flow cats.

 

[ryan101]

If one is stuffed I was thinkn sum hi flows, I have a twin 2 1/2 inch cat back would adding hi flows make any improvment! I'm guessing it would if one cat is stuffed?

 

[SirNemesis]

Yes they will make an improvement, they exist for a reason.

 

[nick_]

If the internal biscuit is stuffed in your cats then they will only rattle on idle. If the welds that secure the heatshields on the cats are buggered then they will rattle at any rpms, any speed,etc.

 

[MR_RX3]

Sounds like cats .. best thing is to just change with hiflows .. job done . give that little extra performance also