Vacuum Pump Air Flow Tests

How much do Racing Vacuum Pumps flow?

We conducted some in-house testing to see how much our pumps flow at different RPM's, and how they stack up against our competitors during the same test conditions. Since we test each pump for airflow when it is manfactured, it was a simple issue to modify our test bench for variable rpm to simulate actual crankshaft speeds. Here's what we learned...

Test Conditions

All tests were done on the SUCTION (inlet) SIDE (just like in an engine) using #10 inlet and outlet fittings with #10 inlet hose and outlet hose. Testing for the Moroso 4 Vane and GZ Super Pro VP104 were conducted with #12 hose. Results for tests could vary with larger or smaller fittings and hose.

Tests done from the outlet side indicated a higher cfm rating which does not appear to be applicable to creating suction or vacuum. All tests were done at a Density Altitude of 4000 feet with no altitude correction. Sea level measurements would tend to be higher. All RPM's are actual pump rpm, not engine rpm.

To compute engine rpm divide the pump pulley diameter by the crank pulley diameter and multiply times the pump rpm. For example a 5.5" dia pump pulley divided by a 3.5" crank pulley = 1.571 X 3500rpm = 5500 Engine RPM. The same pulley sizes and RPM's were used for all comparisions.

Updated Chart Data with New Testing on 12/14/09
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Test Data CFM Values

As you can quickly see, there are some big differences in air flow between the different models and brands of pumps. To learn what size of pump you need on your car, see our Vacuum Pump Application Guide