Rearranged the Hitachi MAF housing to have the airflow going through in the correct direction and also attached part of the stock airbox to try and better replicate the on vehicle airflow into the sensor.

The chart above shows the predicted values for CFM, solid blue line, based on converting kg/hr to CFM; assuming 13.076 cubic feet per pound of air.  The dots are measured readings from the flow bench.

The readings are obtained by slowing increasing airflow, noting the CFM displayed on the digital manometer and corresponding voltage on the multi-meter.

As this was the first time making a full range of readings it’s possible the procedure still needs some improvement.  I noted that with no airflow through the MAF the voltage reading was 0.05 volts.  At the other end, I could obtain voltage readings in excess of 5 volts, recording 500 CFM at 5.12 volts.