I just recently had RT Cats installed on my G35 coupe and mated to my borla exhaust. When i'm stationary and I rev the car, and the revs drop towards idle, I hear a slight buzzing or hissing sound. I pulled over the technician who installed them and he said it was "air resonance" similiar to what the helix straight pipes produce. Is this tell tale signs of an exhaust leak or or is my borla rubbing on something (as far as I can tell it doesn't seem to be)?

I love the way RT cats sound with the borla. It really makes them sound 3x times deeper and meaner.

 

Either you have a leak or your exhaust maybe lightly touching a cross member. If its touching the cross member. See if you can get some shims to lower the cross member a little.

 

if it sounds like a mini nitrous purge sound with decel, its normal.

 

I think your car is about to explode. Find the ***** that sold those used pieces of junk to you and kill him!

 

just a warning... I had an RT cat on my Maxima and about one month after intalling it the cat began to rattle... turns out all the honeycomb type material inside came apart, rattled around and clogged up my exhaust

 

Allright then. Rumor has it he rides around Oviedo, Florida in a laser red coupe with some nifty PIAA Raunchy (or was it Rozzi, I can't remember) wheels. I'm calling G35Sean and the rest of his NYC, vegetarian, "wise" guy friends to have a "talk" with this guy. He'll be sleeping with the fishes by the month's end, rest assured.

 

That's EXACTLY what I have with Megan Racing resonated test pipes and a Borla true dual exhaust. After tightening the hell out of every bolt on the pipes and exhaust, I thought it was the test pipes vibrating. I had brackets welded onto the test pipes and still had whisp! We thought there was something inside the exhaust, so we disconnected the exhaust from the test pipes and finally traced it back to the test pipes. Megan Racing sent me a new set at no additional charge but I haven't put them on yet. I think it's the screening inside the resonators because both sides have been doing it since I put them on.

 

I just installed ultimate racing cats and am experiencing the same type of thing. When I accellerate especially when the car isn't warmed up it buzzes/rattles. Is this normal?

 

I have had the same thing on both the Kinetix HFC's and also the Helix non-resonated test pipes. I really hate that noise, makes your car sound broken