Cubic Feet per Minute (CFM) Calculator
Find the correct CFM.

Fill in the fields below (example: 5000 RPM), click calculate, and we’ll show you the optimal cfm for the street and track! The ratings are different because street engines have a volumetric efficiency around 85% while racing engines are closer to 110%.

CFM Calculations
Maximum Engine RPM Engine Revolutions Per Minute
Engine Size in Cubinc Inches Engine displacement is the volume swept by all the pistons inside the cylinders of a reciprocating engine in a single movement from top dead centre (TDC) to bottom dead centre (BDC). It is commonly specified in cubic centimetres (cc or cm3), litres (l), or (mainly in North America) cubic inches (CID). Engine displacement does not include the total volume of the combustion chamber.
Street Carb CFM
Racing Carb CFM