velocity air meter

A Velocity air meter measures the force of air rushing into an engine against a spring-loaded door in an air tunnel.

Velocity air meters can be rather restrictive, particularly when engines have been modified for significantly greater airflow than stock (e.g. by fitting turbochargers or superchargers).

Velocity air meters have the additional disadvantage that, once the door is fully open, there is no way for the sensor to measure further increases in airflow.

Velocity air meters from Bosch have been commonly used on systems such as older Bosch L-Jetronic and as a part of many factory systems, though they now have mostly been superseded by mass airflow sensors which have many advantages and are less damaging to engine volumetric efficiency (VE).