How Exhaust Systems Work

The Component Parts

An exhaust is not simply a pipe to release waste gasses from an engine. There are various component parts that make up the exhaust system. You may have heard of several of them or you may have been diagnosed requiring a replacement part such as a catalytic converter or back box. We believe in educating our customers so please find below the component parts of the exhaust and their purpose.

Exhaust Manifold

This is connected directly to the engine cylinders and is designed to take gases released from the engine cylinders and channel them into the exhaust system.

Lambda/Oxygen Sensor

Located in the front connecting pipe, this electronic device works with other sensors on the car to measure the proportion of oxygen in the gases as they travel through the car to determine and maintain the level of air to fuel ratio.

Catalytic Converter

This is designed to reduce the number of harmful pollutant gases as they travel through the exhaust system.

Centre Box (Middle Silencer)

This is connected to the catalytic converter with another connecting pipe. The box is lined with baffles which create acoustic filtering chambers to which engine noise and vibrations are reduced.

Back Box

This is the penultimate section placed to the rear of the vehicle and connected to the middle box with further connecting pipes. Similar to the middle box, baffles create more acoustic filtering chambers so engine noise is reduced further.


Often part of the back box, the tailpipe will direct gases out of the exhaust system and away from the vehicle.

Connections & Fittings

The various sections are held to the bottom of the car using exhaust brackets. Between the exhaust system and the base of the car there are several exhaust rubbers, which absorb any movement or vibrations of the exhaust system. Finally there are connecting brackets and seals which connect all the component parts of the exhaust system together.