Horsepower Consumed by Centrifugal Supercharger

Superchargers require power to run, and we thought it would be an interesting experiment to try to determine just how much power was required at various boost levels. To start this test we removed the supercharger belt from the 489" supercharged engine and ran it on the dyno naturally aspirated, to get a baseline horsepower curve. Then, we re-installed the belt and put an adjustable restrictor on the outlet of the supercharger, with a pressure sensor at the outlet to measure the boost. After some experimentation we were able to adjust the restrictor so that at 6000 RPM we got boost levels of 7, 13, and 17 pounds. We also monitored the airflow through the supercharger at these different levels. Boost and airflow at 6000 RPM are plotted on the graph at right, along with the horsepower loss for each pull, as compared to the baseline run. From the graph it is clear that it definitely costs some power to run the centrifugal supercharger.

Supercharger Losses