Silly Rabbit Motorsport Audi B5 S4 exhaust manifolds
The Silly Rabbit Motorsport exhaust manifolds were attached to an adapter that simulates the B5 S4 cylinder head exhaust port in diameter. The adapter is affixed to a flow bench that is operating in exhaust mode and the pressure drop and airflow through each primary runner is measured with the air exiting at the exhaust manifold outlet.
I was a little surprised by how much additional airflow the Silly Rabbit Motorsport manifolds allowed in comparison to the AWE exhaust manifolds. Before putting the SRM product on the bench I looked the part over and made a guess as to they would perform comparatively. I’d guessed that they would flow a little better, not the 20-30% more than the AWE product that they ended up doing.
An additional test using a velocity probe to determine the exhaust manifold outlet airflow velocity was conducted.