NRE Blower/Head flow "Bench"

There is very little factual information on the power requirements of the various blowers and combinations. I have seen two pretty big blower dyno setups and neither directly measured the power required to turn the blower. Most estimates are based on dyno BSFC and other observations. There are also many variables involved.

 

PSI blower dyno

The video below is the very first time Norm Drazy and I spun up a PSI screw blower on the blower dyno (August 1987). As you can see in the video, everything didn't go smoothly on this run.

http://www.youtube.com/watch?v=kGvnOa8H3Xk

Previous to this run-up we had tested a Mooneyham 14-71 over a wide range of blower RPM and manifold pressures. We measured the actual HP required to spin the 14-71 blower at every RPM and manifold pressure combination. We even injected methanol into the hat to simulate the actual operating conditions in the engine. This test was completed at Firebird dragstrip in Chandler AZ.

We also tested the original PSI screw blower (200 mm) over a wide variety of blower RPM and manifold pressures. We measured the airflow rate, manifold pressure and temperature, drive HP required and calculated the volumetric efficiency and compression efficiency for every test. I still have the notebook full of all the original data and computer data reduction that was done at that time. I also have videos for every test (Mooneyham 14-71 and PSI 200 mm screw).

Just to be clear on my current involvement, we all sold PSI in 2006 and I am no longer associated with the PSI business. But that doesn't mean I have forgotton what PSI accomplished in those first 20 years.

Patrick Hale
www.DragRacingPro.com

 

Hey Patrick, can you check your PM inbox? Thanks.