I know this might sound stupid, I know their was sombody who did it recently but can't find them with tha search. I want a good sounding good flowing exhaust. Plans are to do the typical dump over the rear axle. Want to get a 4in in and out muffler. Want to keep the the Y pipe to a single pipe for now,(don't ask I just do). I feel that the single 3in in slowmaster is hurting the performance a quit bit, keeping it caped up..

Thanks John

 

there are several of turbo guys running 4 inch magnaflow diesel muffler, me included. Turbos really hate exhaust tho. I really like the sound, grew on me a lot more than when i first got it put one. For the time being its 3 inch exhaust, 4 inch muffler dam shop couldnt bend any 4 inch.

 

Here's mine

https://www.performancetrucks.net/fo...diesel+exhaust

 

We put a stock 04 duramax catback on my friends 07 classic.
Sounds nice and mean but not very loud.

 

+1 for the magnaflow 4" diesel muffler.

 

I'm running a Mangnaflow 4" diesel cat back system with the 4'' in/out, 30" Mangnafolw muffler. I LOVE the way it sounds WOT, but I have a resanation problelm with it at about 2200+ rpm. That's about 73mph+. It runs clear out the back and dumps down at the bumper. I'm thinking of adding a flex joint right before the cat back flange to see if that helps. I have a 3'' down pipe off the turbo to under the truck then the 4" cat back.

 

I have a stock 2004 duramax 3.5" exhaust on my Ecsb NNBS 2007. It fits pretty well, I just welded new hangars on it. I would have to think a 4" diesel setup would fit ok also.