Mechanically baffled muffler designs are commonly used on moderate to low performance vehicles where power output is a low priority. They function by creating back pressure through mechanically restricting the exhaust gas flow.

Absorption muffler designs can absorb the sound, insulate the shell while keeping exhaust temperature high for total combustion without impeding the flow.

Muffler packing refers to the insulation media (both thermal and acoustical) used

 in Absorption muffler designs. Many of these packing material appear to look very similar, they are actually quite difference and therefore needs to be designed to match the muffler design and specific vehicle performance requirements.

Unlike mechanical baffled mufflers, the insulation packing material may deteriorate over time and with intense use. You can either replace the whole muffler or the insulation for a fraction of the cost. There are several reasons the insulation may need to be replaced, including under-design

insulation, vehicle use beyond the design parameters, or intended schedule replacement in applications such as Nascar vehicles. Failure to replace the packing will not only reduce the performance but can also resulting in permanent damage to the vehicle.

European muffler for absorption design were historically know to be the best in the world, They were the most durable and highest performing. The regulatory requirements were also the most strict. North American manufactures of high end aftermarket exhaust system learn to meet and even out perform these imported systems, but were forced to import the packing materials driving up their cost.

Now with BCI RaceTEX products North American manufactures now have a domestic source of these high performance thermos-acoustical insulation packing materials.