The muffler serves to muffle the noise coming out of the engine. Exhaust gases leave the engine under extremely high pressure. If these gases escaped directly from the engine the noise would be tremendous. Therefore, the exhaust manifold sends the gases to a muffler where they go through metal plates, or tubes, with a series of holes.
The Muffler is attached to the exhaust stack of the engine to reduce noise and increase back pressure which helps low speed performance. The pressure of the gases is reduced when they pass through the muffler, so they go out of the tail pipe quietly. Made of metal, the muffler is located underneath the body of the car. It is connected between the tail pipe and the catalytic converter. Performance cars have modified mufflers to increase air flow and also, sometimes to incrase noise. There are two types of muffler designs. While one type uses several baffled chambers to reduce noise, the other sends the gases straight through perforated pipe wrapped in metal or fiberglass. This type of muffler is designed for the purpose of reducing backpressure and, consequently, makes slightly more noise.