Engine Airflow CFM Calculator

Inputs

Displacement (V_d)

Total engine displacement.

cm³

Engine speed (n)

Crankshaft speed.

rpm

Volumetric efficiency (VE)

Cylinder filling efficiency.

Ambient pressure (P_a)

Ambient absolute pressure.

bar

Boost gauge pressure (P_b)

Manifold boost above ambient. Leave zero for naturally aspirated.

bar

Air density (rho)

Air density used for mass flow.

kg/m³

Default result

Engine airflow(Q)

923.4m³/h

Pass

Also computed

Mass airflow(m_dot)0.3142kg/s

Pressure ratio1.000

Method notes 2 notes

Uses the four-stroke airflow relation: displacement times RPM divided by two, adjusted by VE and pressure ratio.
This is a sizing screen. Real airflow depends on temperature, humidity, intercooler pressure drop, cam timing, compressor map and manifold losses.