Originally Posted by 03whitegsr

I found a copy of the FSM and it had some interesting points about this sensor and how the ECU calculates airflow.



The sensor is a 0-5V output, not frequency unfortunately so whatever needs to be done for a Subaru sensor is the same that needs to be done for this sensor. Honestly though, the two sensors look very similar, they may even be the same sensor.



When used with the factory airbox

0.2 VDC = 0 g/s

1.8 VDC = 10 g/s

3.5 VDC = 119 g/s

4.9 VDC = 387 g/s



The MAF sensor has a built in thermistor which looks to have roughly the same scaling as the EVO VIII-IX IAT sensor in the stock MAF. This is just from memory though and I'd have to look at my notes to be sure. The X has two separate air temp sensors though and may deal with fuel enrichment very differently because of the two sensors.



The Baro sensor on the X is in the ECU. I also think it mimics the VIII-IX baro sensor on scaling but would have to look at my notes again. The X also has the 3-bar MAP sensor so there is likely additional mapping to accommodate MAP correction trims.





If an internal diameter measurement of the factory air inlet was taken near the airflow meter, we could probably calibrate it for other tube sizes pretty easily.