Required Intake CFM This calculator will help you determine your engine's intake CFM requirements. Enter the engine's displacement, Volumetric Efficiency, and its redline.
The calculator will tell you the CFM range you need.
VE is affected by intake type, camshaft grind and type,
boost, and many other factors.
Here are some guidelines.
Factory engine: 65%-75%
Mild street performance, flat-tappet cam: 80% - 83%
Mild street performance, roller cam: 90% - 93%
All-out race engine, 95%-105%
Blown engines, typically over 100% or higher, depending on amount