The disparity between the flow bench readings and the MAF Sensor conversion table, MLHFM, was larger than I was expecting to see even accounting for the rough calculation from kg/hr to CFM.

I checked the 5v output from the ATX power supply and observed that it was providing 5.138v, a good amount more than I would have liked given the sensitivity of the MAF sensor.  I decided that I would try using a dedicated 5v power converter to provide the MAF sensor with its 5v supply.  I had previously checked this other power supply, and due to the ability to tweak the output voltage I had been able to get 5.005v from the device.

With the new power supply in place I ran the Hitachi sensor on the flow bench again.

This time the results I obtained were:

Based on these results it’s starting to look like I’ll need to tweak the power supply to get the bench readings in-line with the stock predicted values, and then I can move on to checking an 85mm housing.