This calculator gives the baseline horsepower and cubic feet per minute (cfm) that an engine will develop at its maximum rpm given the volumetric efficiency of the engine. A guide on volumetric efficiency values is provided below.

cubic inchesthe total displacement of the engine in cubic inches (see our cid calculator)
max rpmthe engines maximum rpm limit
volumetric efficiencythe volumetric efficiency is a measure of the efficiency of the engine moving the intake charge into the chamber and the exhaust out. Typical values are as follows:

2 valve head – 80%

4 valve head – 88%

it is not unusual however to have VE’s of 95% or more in correctly built race engines
cubic feet per minutethe total cubic feet per minute of air that the engine will consume
brake horsepowerthe brake horsepower of the engine at the flywheel
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