Frequently Asked Questions - MAF - Mass Air Flow Sensor

1. What is a MAF and why is it different from a MAP sensor?

A Mass Air Flow (MAF) sensor is used to determine the mass of air entering the engine. The air mass information is necessary for the ECU to calculate and deliver the correct fuel mass to the engine.

A MAP (Manifold Absolute Pressure) sensor reads the pressure of the air in the intake manifold, which is then used by the ECU, along with other sensors, to calculate and deliver the correct fuelling.

A MAP sensor alone is incapable of giving results as accurate as those given by a MAF sensor as the method the MAP sensor uses is not able to take into account the properties of the ambient air, such as temperature and density.

2. Why do I need a 95mm MAF?

The 95mm MAF housing from C2 enables the sensor to be able to read a greater throughput of air that is needed by engines with forced induction systems. Without the C2 housing, the ECU will be unable to read sufficient air mass.

3. Is there a specific way a MAF has to be fitted?

Yes. It is imperative that the MAF is fitted so that the air flows over the sensor in the correct direction. On standard Bosch/VW MAF sensors, the correct air flow direction is indicated by an arrow on the sensor itself.