The sound is louder, or more distinguishable at 1600 and 2100 RPM.. Like thin metal vibrating against each other. Could a vibration in the pipe make its way and sound as if it were coming from the engine compartment? Thanks again.

 

could get someone to hold the motor at the right rpms while you check around with welding gloves on, grabbing shields and whatever to see if you can get the rattle to stop. could be the converter doin it and the sound is traveling up the pipe to the manifold.

 

Ive read in another post, that there is a pipe inside the exhaust pipe at the Y..? Could it have loosened and is vibrating? Anyone had this experience?

 

no double posts, i have merged the two threads to one for you.

 

im pretty sure theres not a pipe in a pipe

 

I read in another thread that there is another pipe inside some areas of the Y pipe, or up from the cat some where in the pipe..? And that they can loosen over time and cause a vibration..? I assume its there for strengthening the pipe. If anyone can confirm. Sounds more like the noise is coming from the pass side, just up from the Y, or the exhaust manifold and noticeable at like 1600 and 2100 RPM..??? I've checked the heat shield more than once.

 

Determined the sound is coming from the passenger side. Or in the pipe, just after the Y. I read in another post, that there is a pipe inside the exhaust pipe just after the cat, that loosens and causes a vibration. Anyone confirm or know what this sound is? Noise occurs at 1600 and 2100 RPM.. ?

 

Don't know about a pipe insidethe exhaust but I know the connection after the cat gets loose and rattles. Mine did that until I welded it.

 

I'll check that.. Thanks.

 

Problem solved! The crossover pipe IS double piped, from the cat up to the manifolds. In time, the inner loosens and vibrates. It was the passenger side primarily on my car. If your Camaro is making this noise, you know it!
I heated the pipe with a torch, to red hot, (in suspecting areas) than with a large pair of channel locks, crimped that bad boy! If you can bend it enough, the outer pipe will hold the inner. These pipes are stout, so this wont work unless it's heated. Try to get as high as you can up the pipe to the manifolds (safely), as this seems to be the problem areas. I was able to hear the loose areas on mine by tapping the pipe and listening.
Sound is gone. I tried to figure this out off and on for 6 months!
Hope this helps.