Exhaust flow tests

034 Motorsports 3.5″ single exhaust system, 3″ mid-pipes with high-flow catalytic converters and dual magnaflow mufflers, was attached to the flowbench to get some idea of what kind of pressure losses a high performance aftermarket exhaust causes.

The setup

034 Motorsport exhaust

The first test was done on just the exhaust.  A second test was run with 3″ downpipes attached to the exhaust.  I use the Autospeed downpipes, I doubt there is any difference in flow characteristics of the ASP downpipes and other 3″ downpipe options.

With the downpipes attached:

Autospeed downpipes

For both tests some play-doh was attached to the edge of the pipe entrance to create a shape more like a bell-mouth.  Prior test have shown that the sharp edge at the entrance can lower airflow slightly.

The Results:

Exhaust pressure drop

Exhaust airflow


Until I can get around to testing a stock setup it will be difficult to assess these results.  The pressure losses caused by this setup seem minimal.

Audi B5 S4 Information and Testing