Pro-M Racing Range Extender Facts

Range extenders do not actually extend the range of a mass air sensor at all. In fact, they should be called range reducers, since they actually reduce the voltage range of the sensor, which effectively reduces the overall resolution the MAF meter.

To fully understand this, you must first understand how a mass air sensor works. Put simply, a mass air sensor outputs a voltage signal relative to a given air flow. A typical mass air sensor will output a voltage range from 0 to 5.5 volts (although a typical engine computer will only recognize up to 4.99 volts), measured from an air flow range of 0 to 1000 kilograms per hour (KG/HR). In other words, at zero air flow, the sensor will output zero volts. At 1000 KG/HR, the sensor will output 5.5 volts. The voltage vs. airflow of a sensor is known as its “transfer function”.

Although they typically come in fancy packaging, range extenders are comprised of nothing more than a simple resistor installed in the signal wire between the mass air sensor and the engine computer. This will reduce the output voltage of the sensor at any given air flow. Let’s say that this particular range extender will cut the voltage output by 1 volt. Your voltage range is now 0 to 4.5 volts, but this still represents the same range of air flow! The only advantage to this is that the entire voltage range (and airflow range) of the sensor is now within the usable range of the engine computer. But the benefit is extremely limited. This will only help you if the meter you were using had a range only slightly less than needed. Keep in mind that the mass air sensor itself still has the ability to output a maximum voltage up to 5.5 volts, but the resistor limits its overall output to the engine computer to only 4.5 volts. The meters range really has not been extended at all.

The only truly useful way to extend the range of a sensor is to calibrate it properly for the application. This involves calibrating the electronics of the sensor itself, not manipulating it with an external device. In other words, we make the voltage output of the sensor represent a greater air flow. For example, let’s say we needed to double the range of the sensor. The sensor would still have a voltage range of 0 to 5.5 volts, and zero volts would still represent zero air flow, but 5.5 volts would now represent 2000 KG/HR (rather than 1000 as before). The range of the sensor is now doubled, with spot on accuracy.

Pro-M Racing is the only aftermarket company that possesses the physical and intellectual resources to perform this properly. Make no mistake; there is NO other aftermarket company, regardless of their claims, that has the ability to match the quality and performance of a Pro-M product.

Copyright © 2023 Mass-Flo EFI, Inc. & Pro-M Racing, Inc. All rights reserved. Mass-Flo EFI, Inc 77 Snow Road, West Brookfield, MA 01585