H8 B N SLO

I bought a cut out from Summit Racing and installed it and everything was fine for a few days. The car developed a rattle, buzzing sound coming from under the car but has progessively gotten worse to the point that it is EXTREMELY loud between 1500-2k RPM, I mean loud enough to be heard over the open cut out at full throttle.
I got under the cat to make sure the exhaust wasnt making contact or the the heat shields weren't making the noise. I could not locate anything so I had my wife rev the car while I was under it to see if I could find the source.
The noise is actually coming out of the cutout!
This isn't just a small rattle but is extremely loud and sounds like a metal on metal buzzing sound, very similar to the sound the car made when I hadn't tightened the clamp on the exhaust all the way and the clamp had slid down the I-pipe. The entire exhaust is now welded together except for where the I-pipe connects to the y-pipe. That clamp was checked several times and even switched with a different clamp to make sure it wasn't that. I do not have aftermrket headers or y-pipe yet so I don't think it is any of those connections.
Like I said, the noise is actually coming out of the cut out. I put the plate back on and it reduces the noise a lot but is still noticable.
I am worried that I have damaged something but not sure what it would be. There are no strange noises coming from the egine bay, the car is running fine, no SES lights or anything.
Has any one else had this problem or have any suggestions on what to look for?

Mike K.

maybe you are shaking something loose, where is the cutout located, is it pointing towards anything? Also the welds are good I assume? The only other thing I can think of right now is if you have some sort of body flex that is causing the cutout or exhaust to hit the car chassis at some point.

H8 B N SLO

All the welds are fine. I have checked and double checked for the exhaust making contact, loose fittngs, looe heat shields ad everything else that would make noise. I cant find anything.
The cutout is toward the back of the I-pipe and dumps under the back passengers side seat aimed down and to the side.
The noise is not coming frm there it is actually coming from the exhaust opening itself.
Even with the cutout capped it still makes the noise although not as loud.

RED01SSCAMARO

i had the same noise. it was one of the cats rattling from something loose inside.

NHRA T/A

I've got the same rattle/buzz. I've just learned to live with it.

H8 B N SLO

I am going to order a set of LTs and offroad pipe and see if that solves the problem. I have been wanting to do it anyway, now this just gives me an excuse to tell the wife.

WS6snake-eater

I have the same exact problem...When I open my QTEC I get some king of crazy *** rattle and resonence. It is anoying as hell. If I close it off, it pretty much goes away. If you figure it out let me know..I put the car on the lift yesterday and looked all over the place, and can't figure it out. Mine only does it at idle, it will go away if I start to rev.