Review on Dynomax 21172 Commercial Vehicle Muffler by Redfish Rosenhoover

If you are purchasing this muffler expecting it to have a perforated core that is fiberglass filled throughout like ALL other Ultra-Flo mufflers, please note: this is not the case. t. This silencer is one of the strangest I've ever seen. At both ends of the muffler, just inside the intake ports, is a short perforated section, maybe 4 inches long or so. These sections are surrounded by fiberglass padding. Aside from that, however, it just opens up in the middle of the muffler. into a very large open chamber with nothing in it. I don't really know if this open area is meant to act as some sort of resonator. If you're looking for a noisy muffler, this will help. But if you're looking for a loud muffler, you probably aren't looking for a huge, bulky muffler like this, are you? Looking for a quiet muffler (like me), keep looking because it's not.