Most of you guys know I installed the Magnaflow cat back system on my 06 QC. I had a friend drive it around while I stood in the parking lot.

It sounds great from outside and I love it, BUT the interior resonance is so bad I am considering returning it. You can't hear a thing around 2500 RPM's. When I tow the boat - forget having a conversation with anyone - doesn't matter if using tow mode or not. Cruise on the highway is not bad at all but there is that certain power curve where it is just annoying as crap. Unfortunately that is where I do most of my driving. Anyone come across this with other cat back systems?

I have double checked and double tightened everything with no succes on quieting it down in the cab.

 

one of the reasons I removed and returned the JBA catback I bought after 15 mins of driving.

 

I had 3" pipe from the cat back with a Flowmaster 40 installed. Never really paid attention to the rpm's. But between 30-40 mph there is a lot of resonance until the tranny shifts. Then it's all good. Even at 70 there is not much to talk about. Boy does she growl when going up a steep hill and the overdrive is off! Maybe look into getting the area under the cab undercoated or have it shot with Line-X or Rhino Coat. Or change mufflers.

TASTE THE HEAT AND ENJOY THE PAIN

 

Wow, Magnaflow loud? Thats just about the quietest out I think heh. Maybe try a 50 series Delta Flow? Supposed to cut down interior resonance.

 

Ok, the magnaflow is boxed up ready to be returned. I even tried to get my local shop to help me out with it. They could not reduce the interior noise level.

I love the quality and sound (from the outside) of the system but the interior noise level is to much to deal with. You can't even have a conversation with someone. I've spent every extra hour adjusting, tourqing, talking with magnaflow, etc.

So what next? Is it possible I got a bad kit? Should I take a chance on another one? I like Frenchy's mod. Any ideas?

 

Do you also have a new CAI? Mine is loud on the inside of the truck when I'm stepping on it up to about 3500. But if I'm taking off normally, I don't hear the noise at all.

Try like I said. I bought the muffler and had the muffler guy customize my exhaust with the Magnaflow muffler, and kept the one resonator on. It's just a straight through pipe with a muffler wrapped around it. It splits behind both wheels and is a dual exhaust.

 

After building a system from scratch, using FLOWMASTER 1-in-2-out muffler, I heard the resonance inside also. It was really loud. I welded an 18-inch resonator in front of the muffler and it's much better. The muffler cost $92 but the rest was quite inexpensive and I friend bent the duals in back. I welded megaphone tips to the end and it's great now.
Also used Airraid CAI but haven't put the throttle-body plate in yet. I notice a little power improvement but mostly it sounds great.

 

I just bought a gibson cat back and waiting for it to come in. I am worried about it being too noisy in the cabin. I want the truck to sound good but also like how quiet the cab it. I know I will hear it but hopefully doesnt shake the interior. I also read rhinolining the bed will quiet it down, hate to spend 800 on a cloro match liner to quiet new exhaust down!

 

my 3 inch single cat back was loud. its the imco one matched to the truck.after awhile it began to lose some of the loudness. but like always when i did not want to here the noise it was there. a quick fix was take muffler from original spot and move it farther down the system and put a bed rug in. dont know how this will help with the dual exhaust people. also try installing a dyno mat. costly, but effectively.

 

I've had a Gibson cat-back single exhaust on my 05. Sounds sweet. The reason you guys are all complaining about the flowmaster is the reason I stayed away and went with the gibson.

Safari-rick