Exhaust Noise

bigb · December 8, 2003

I installed a Magnaflow cat back exhaust system on my 2002 1500HD several months ago and have been disappointed in the noise in the cab. From about 1500 to 1900 rpm, which is cruising speed on the highway in overdrive, the exhaust produces a deep, loud annoying tone. I either have to run faster to keep the rpm up or shift the tranny into 3rd gear. I called Magnaflow about the problem and the technical rep said that was as quiet as they could make the system because of the displacement of the motor. I work for a guy that has a new Hummer H2 with a 6.0L like mine that he put exhaust on with no major noise. I am thinking it must have something to do with the larger pipe diameter on my truck or the length of pipe. The exhaust sounds good otherwise and I don't want to replace it. I have considered insulating the cab but I am not too thrilled about doing that either.

Please let me know if anyone else has a similar problem or has any good advice.

GM GIMP · December 8, 2003

Your problem is almost exactly like mine.

I have a 2002 GMC 1500HD with a gibson single exhaust

that I was told would not resonate. It drives me nuts. I'm thinking about going back to a stock muffler

unless someone has a better idea.

lrymal · December 8, 2003

Seems we can't win for losing. I have always wondered what is it about the factory exhaust that eliminates the interior drone... I'm disappointed to hear the Gibson has this problem. I was considering it.

I tried the CORSA on mine. But, the opposite occurs. Ther is no drone, but under WOT, the exhaust sounds like a bubba East Texas red-neck truck, pure ratty raspy sound. I tried tolerating the exhaust for a few days and then removed it, putting the factory back on. Indeed, some of my friends asked what was wrong with the exhaust---not what you want to hear with a 10 month old truck.

On my Pontiac GrandAm, I tried the BORLA and the resonance was unreal. I put the factory exhaust back on that one, also.

Regarding insulation. It helps, but will not kill resonance and it is still annoying. However, insulation will quieten any vehicle for other reasons. Not a bad idea anyway.

I think so much of the problem with these aftermarket exhausts for us is that we can't "try before you buy". For the most part, resonance doesn't seem to be an objection to many enthusiasts. Can't tell you how many times I have been told to just turn up the radio.

Machine · December 8, 2003

I had the Borla cat-back on my Escalade and it drove me nuts. I replaced the Borla muffler with the biggest Magnaflow that would fit the borla pipes...it's MUCH better.

My Duramax sounds like a Peterbuilt under WOT but is nice and quite at cruise, thank God.