Estimate the required airflow (CFM) for your internal combustion engine.
Engine Specs
Calculation Results
Enter engine specs to calculate CFM
About this calculator
Overview
CFM (Cubic Feet per Minute) is the measure of airflow an engine requires. Choosing the right size carburetor ensures optimal air-fuel mixing across the RPM range.
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Pro Tips
CID = Cubic Inch Displacement. (e.g., a 5.7L engine is roughly 350 CID).
Most stock engines operate around 80% Volumetric Efficiency (VE).
Over-sizing a carburetor (too much CFM) can lead to poor low-end response and 'bogging'.
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Fun Facts
"The '3456' in the formula comes from converting cubic inches to cubic feet and accounting for a 4-stroke engine firing every 2 rotations."
"High-performance racing engines with tuned intakes can exceed 100% Volumetric Efficiency."
"Holley and Edelbrock are two of the most famous manufacturers of aftermarket carburetors."
