Engine data
Operating point
Estimated airflow
Enter your engine data to estimate airflow.
How this MAF estimate works
For a four-stroke engine, actual volume flow is displacement × RPM ÷ 120 × volumetric efficiency, using cubic metres and efficiency as a fraction. Air density is absolute pressure ÷ (287.05 × temperature in Kelvin). Mass flow is volume flow × density.
Worked example
A 2.0-litre engine at 3,000 RPM, 90% volumetric efficiency, 20°C and 100 kPa absolute intake pressure produces an estimate of 45 litres per second and about 53.5 g/s.
Comparing measured MAF readings
Enter manifold absolute pressure, adding atmospheric pressure to a gauge boost reading. For boosted engines use the post-intercooler temperature. Volume outputs describe actual flow at these conditions, rather than standard CFM.
Compare measurements at the same operating point. Volumetric efficiency, EGR, leaks and transient conditions affect the comparison. This estimates total intake gas flow using dry-air properties; it does not prove a fresh-air MAF sensor is correct or supply a sensor scaling curve.
Convert pressure and airflow units. Formula reference: NASA mass flow rate.
Llandow Tuning Technical Resources
These calculators are provided free of charge and without warranty. While we strive for accuracy, we recommend verifying critical calculations. If you have any technical or mathematical questions regarding their use, feel free to reach out to us.