Volumetric Efficiency Calculator
How completely the engine fills its cylinders. Work it from measured airflow, or back it out of a known power figure.
| Volumetric efficiency | 98.7 | % |
| Theoretical airflow at 100% VE | 607.6 | CFM |
- theoretical CFM = displacement × RPM ÷ 3456
- VE % = measured CFM ÷ theoretical CFM × 100
When you need it
When sanity-checking a power claim, and when judging how much is realistically left in a combination before you spend money on it.
Over one hundred percent is normal
At the torque peak, intake runner tuning and exhaust scavenging can pack in more air than the swept volume of the cylinder. A well-developed naturally aspirated engine will exceed a hundred percent across a narrow band around peak torque. Seeing a number above a hundred is not an error.
Working back from horsepower is an estimate
That method assumes a brake specific fuel consumption and an air-fuel ratio. If either assumption is off, the VE it reports is off by the same proportion. It is useful for a rough cross-check on whether a claimed power figure is physically plausible for the displacement and RPM.
Measured airflow is the honest input. If you have flow bench or dyno airflow data, use it.