Boy-racers will enjoy the sound of a loud muffler note and playing around with the design of the exhaust and muffler to gain an increase in engine power. However, in order to reduce the noise of the combustion engine, the exhaust gases need to be passed through an appropriate muffler to meet the legal noise level requirements.

The muffler is designed for the exhaust gases to expand slowly. If the gases are allowed to expand too quickly then the resulting noise can be quite deafening. Muffler design needs to quieten the noise of flowing exhaust gases without creating too much backward pressure on the exhaust gas flow. If considerable backward pressure occurs, then the free flow of exhaust gases is stifled and engine power is compromised as a result of not all of the burned gases being forced from the cylinders efficiently. As well as a loss of engine power, the fuel consumption will increase as backward pressure increases.

Muffler design varies from one manufacturer to another but essentially, the muffler chamber is attached to the exhaust pipe with the one function in mind: to muffle/lessen the noise of the flowing exhaust gases.

Occasionally the sound-absorbing material inside the muffler doesn’t last the distance and needs to be replaced. This is quite common; and in Australia there are oodles of muffler servicing and replacement outlets nationwide.We hope that helps answer the question ‘What is What is a Muffler?’!

Back to Car Glossary