Exhaust System
Exhaust SystemThe (E85) Z4 exhaust system is designed for the sporting engine sound of a roadster. The exhaust systems for the M54B25 and M54B30 engines are identical. The exhaust system consists of the following components:
^ Exhaust manifold (with catalytic converter, cylinders 1-3)
^ Exhaust manifold (with catalytic converter, cylinders 4-6)
^ Front silencer
^ Center silencer
^ Rear silencer (with tailpipes).
Each exhaust manifold forms a component together with the catalytic converter housing.
In the catalytic converter housing, a metal monolith pre-catalytic converter and a metal monolith main catalytic converter are arranged in sequence.
1. Oxygen sensors (primary oxygen sensors, Bosch LSH-25)
2. Lambda sensors (secondary oxygen sensors, Bosch LSH-25)
3. Catalytic converter housing (cylinders 1-3)
4. Catalytic converter housing (cylinders 4-6)
The front silencer has a volume of 3.4 litres. The center silencer has a volume of 1.5 litres. The rear silencer has a volume of 22.7 litres. The two oval tailpipes and the rear silencer form one component. In order to absorb oscillations and noises, the rear silencer is fitted with a rubber damper.