I want to reduce back pressure, and make my dmax louder but still clean sounding. Some guys run straight pipes but ive never herd one on a dmax. The powerstroke with straight pipes has to much of a poping sound on top end. i dont like that. Will mine do that? or where can i buy a highflow, clean sounding louder muffler without the full system. i just want a muffler or if sounds good, straight pipes. input would be greatly appriciated!

I had my muffler removed and sounds great. It only cost me $35. If you did that and didn't like the sound, you can replace easily and cheap.

Ben

You can also just replace the factory muffler with a straight-thru 4" variety. Has nice, deep rumble at idle and not too loud on the road. I understand the factory muffler necks down to very small pipe internally, which is the real bottle neck in the system. Getting rid of it will help a lot. Of course, for not a lot more, you can get a good 4" system. The gains won't be as dramatic as replacing the muffler alone, but it won't hurt and has a distinctly higher macho quotient.

TC

If you dont want any popping then be sure not to put a big tip on it, my friend has a 5" tip on his and it pops pretty bad, still sounds good though

My bully dog 4" sounds like an old muscle car. Not sure if you can but maybe try to buy just the muffler from bully dog. there is no restriction through the muffler, pretty much wide open.

Flowmaster makes a Duramax replacement muffler.
IMO sounds great.

Donaldson part number M101167. no drone, and a clean crisp sound. I had the straight thru and it drove me crazy. It has a nice sound at open throttle.

It's a 4" muffler

My 5" system is a little loud on acceleration, but can hardly hear it going down the road. After I removed the muffler, it got rid of the drone.

Moving to Exhaust section.

Just Put On A Straight Pipe It Sounds Good,but At Certain Rpms It Echos Thru The Cab. Otherwise Noticed A Huge Difference In Power And Mileage Is Better