How Exhaust Baffles Work

Exhaust Baffle

The exhaust baffle is a chamber inside a muffler or resonator that is designed to muffle or silence the otherwise loud exhaust system. Ingeniously, the muffler uses the baffle chamber to increase the amount of internal sound inside the chamber so by the time it exits the muffler, the sound cancels itself out. Exhaust is spent fuel and air of an internal combustion engine and is extremely loud coming from the cylinders of the engine. An exhaust system controls the sound through a manifold and a series of pipes, a catalytic converter (on vehicles) and the muffler. In some applications, resonators are present in the exhaust pipes that act as a second (or more) muffler on the system. Inside the muffler or resonator is a sealed chamber with two or more perforated tubes. The inlet perforated tube allows the exhaust to emit into the baffle chamber, bounce off the interior walls and enter into the outlet perforated tube where it is then directed by back pressure through the tailpipe of the muffler. The perforated tubes in the baffle chamber create a nondirectional interference with the flow of the back pressured exhaust and assist in silencing the exhaust.

Perforated Tubes

There are adjustable or do-it-yourself baffle kits that can be manipulated and inserted into the exhaust system muffler (most common on motorcycle mufflers) to change the pitch of an exhaust to either intensify or decrease the amount of sound the exhaust system emits. By doing so, these baffles can increase the horsepower of the engine (for racing), which subsequently decreases the fuel efficiency of the vehicle. Conversely, a quieter, more controlled sound can be achieved.

Wear and Tear

After time, wear and tear and exposure, exhaust systems deteriorate. Due to condensation of heating and cooling, muffler and internal baffles can fail internally. Even if the muffler is not leaking, a deteriorated perforated tube in the baffled chamber of a muffler can create an annoying rattle during normal operation of the vehicle. Damage to the tube in the baffled chamber would require the replacement of the muffler and or attaching new pipes to restore the system.