The initial test of my 034 single 3.5″ system exhaust back pressure with the OTC gauge was unremarkable.  As can be seen from the video this was done with the car stationary, so it wasn’t pushing the maximum airflow possible with this turbo setup.  Still the results are positive, the needle barely moves when engine speed is run up to 4000 rpm.  The gauge scale is from 0-8 psi and the OTC gauge line is plugged into the O2 sensor bung at the bottom of the downpipe that I normally use for a wideband oxygen sensor.

Here’s a picture of the full 034 exhaust setup that I have.  This has 3″ mid-pipes with catalytic converters and two Magnaflow mufflers along the single 3.5″ section of piping.