Join Date: Mar 2009
Location: Northern New Jersey
Buzzing sound in area of HFC and alignment question
I recently installed a solo mach balanced cat back and high flow cats on my GXP. Nothing is rubbing or touching the heat shields or floor pan. When parked if I rev the engine to 3,000 RPM and let off I get a rattle/ buzzing sound that can also be produced by keeping the rev’s around 2,000 RPM. Sound is coming from the area of the passenger side cat and I can see a noticeable vibration in the cat when the buzz/rattle is heard. Hope it’s not the substrate rattling in the casing causing the buzz. Have not been under the car yet to check but want to see if anyone else experienced this.
Other two issues I have are the system is nicely aligned overall but I am having a slight issue as the tips are slightly pointing in toward the center line of the car a bit too much for my tastes. Passenger side is almost perfect but driver’s side could use some tweaking. Hight wise they are good. Don’t think any washers on the hangers will help much but maybe futher up the line? Additionally I have a leak both axel connection but only condensation (water comes out) no soot at connection or the usual sound of a exhaust leak. Just two small puddles of water on the ground by the joints that stop when the system heats up and expands. My Audi S4 used to do this also and never was a problem. All clamps are centered and tight.
Last edited by stibuki; 08-03-2010 at 10:25 AM.