Review on Silent Performance: Unleash the Power with MBRP M1004A Universal Quiet Tone Muffler by Anthony Payton

My 2006 Dodge 5.9 Cummins has had a 4 inch straight pipe for the last few years. That's not my daily driver. It's fun around town but after 2 hours with a heavy trailer my eardrums get really heavy so I bought my MBRP truck for Christmas. Wow what a difference. The first thing that struck me was how much smoother the motor sounds. It's a more comfortable experience across the board: in the cockpit, standing next to it at idle, the windows are down when the throttle is close to the block wall. I'd say it's about 3-3/8" net ID through the orifice. Also around the ID are 3/8" high nozzles that direct some of the gas into the expansion chamber. The effective opening is about 4" tubes. In the picture it looks like each row is reduced to a smaller ID, but that is due to the angle of the picture. Each subsequent row has the same final inside diameter as the first row. Muffler does not directional (equal on both sides). 30" OAL and 6 OD still chamber. The chamber is also hollow. There is no sound-absorbing material inside. Still sounds and flows MUCH better than the stock 5.9 Cummins.