Unlike other competitor muffler designs, Flowmaster does not use a “straight-through” design for their mufflers.  Straight-through designs use a packing material packed around a piece of perforated tubing to dampen sound as the exhaust flows through the muffler.  This packing can deteriorate over time and become less effective in its sound reduction functionality.  The internal tubing with this type of muffler usually is reduced in size as it enters the inlet of the muffler, which further reduces the sound as the exhaust flow is leaving the muffler.  Unfortunately, this reduced size tubing tends to restrict the flow of exhaust gas as it moves through the muffler, reducing the performance potential. Flowmaster mufflers utilize sound energy ca...

Recently Flowmaster received a story that perfectly illustrates the difference a properly designed exhaust can make – and the negative impact an improperly designed exhaust system can have on performance.  A client told Flowmaster the story about his highly customized 1968 Mustang, into which he had put a significant amount of money for the drivetrain, only to find when he put it on a dyno that he was only getting 258 horsepower (out of a 427cid, 485hp engine!).  The problem was so severe that the shop who was working on the Mustang even wondered if the engine was damaged, and began preparation for the process of tearing the engine down to inspect it.  As the exhaust system was removed from the car, the mechanic noted the small diameter tubing and the small, roun...