Just got back from a track day, and started to hear a rattling type of noise coming from my exhaust, it happens when I lift off the gas and change gears, especially the 1->2 and 2->3 shift. Got my girlfriend to rev it in neutral while I looked at the exhaust, the rattling sound came out of the muffler, and the muffler was spitting out water and soot. I gave the muffler a little shake, no rattling sound. Tapped the cat and no rattling sound. Rattling sound is only audible when accelerating around the 2000rpm mark and lifting off the throttle.

I am using Buddy Club Spec 3 Axle back bolted up to a Carsound cat. The exhaust isnt rubbing against anything. Did a search and couldn't find much, any idea what it could be?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jim80y &raquo;</TD></TR><TR><TD CLASS="quote">Just got back from a track day, and started to hear a rattling type of noise coming from my exhaust, it happens when I lift off the gas and change gears, especially the 1-&gt;2 and 2-&gt;3 shift. Got my girlfriend to rev it in neutral while I looked at the exhaust, the rattling sound came out of the muffler, and the muffler was spitting out water and soot. I gave the muffler a little shake, no rattling sound. Tapped the cat and no rattling sound. Rattling sound is only audible when accelerating around the 2000rpm mark and lifting off the throttle.

I am using Buddy Club Spec 3 Axle back bolted up to a Carsound cat. The exhaust isnt rubbing against anything. Did a search and couldn't find much, any idea what it could be?
</TD></TR></TABLE>

Its that crap car sound cat....

 

could be your cat. I had a similar problem

 

check to see if the o2 sensor on the cat is loose. i know you said the noise was from the muffler, but it can't hurt to check.

 

No 02 sensor on the cat. Is it possible that it's the heatshields on the cat even though the sound is coming from the muffler?