Published cylinder head airflow figures are not equal. It is often difficult to compare cylinder heads and other components if the provided specification data uses varying flow test values. Flow figures are compiled with the help of a flow bench. However, the technician collecting the data may use non-standard measurement values due to the geographic testing location, capacity of the equipment used, or some other consideration or limitation.

Manufacturers, engine builders, or testers avoid standard measurement values for a variety of reasons, but there is a solution! When the need arises to compare advertised or tested airflow data between products, it is possible to convert the test data to identical values if we know the proper mathematical multiplier. A better choice is to convert the values to the industry standard of 28″ of water. Either is possible, and allows for equal comparison of quoted airflow values.

One simple solution is to use the table provided below to calculate corrected airflow data from provided, non-standard values.