Exhaust System

Exhaust Manifolds:

The M73 engine uses twin walled steel exhaust manifolds similar to the M50. The steel pipe heats up quicker than the cast iron manifolds of the M70 engine allowing the exhaust heat to reach the catalytic converters quicker.

The twin wall design of the manifold creates an air insulation barrier which keeps the internal pipe hotter than the external pipe which additionally passes the exhaust heat to the catalytic converters. The twin wall also reduces exhaust noise.

The internal size of the inner pipe has more area than the M70 cast manifolds. This is necessary due to the additional engine displacement and increased exhaust gas transfer.