Originally posted by warmonger:
Combined with all the electronics a 5v reference source is passed through the circuit and the varying resistance causes a voltage drop that the pcm compares with its stored data.



I'm sorry but you're wrong. There is no 5 volt reference. It uses battery voltage. Check out this schematic. It divides the battery voltage across the hot wire and a resistor. All Ford has to do is swap one resistor to change the calibration. Also, if it was limited to 5 volts, I couldn't do this...



I just used my compressed air tank. There you go, 6.522 volts. I also made a movie where it peaked around 7.2 volts. I really can't provide more evidence than that.

Originally posted by warmonger:
BTW, your aren't improving the resolution by changing the voltage if the pcm is still looking for the same voltage ranges. It will just approximate the closest value.
If your maf worked on a 0-5v scale but your intermediate circuitry allowed you to sense a voltage change down to the hundreths's column that reflected a change in airflow, THEN your resolution is improved. You have just possibly changed the range by changing the operating voltage range; and THAT would mean that your equipment isn't that precise and so therefore you needed a larger voltage range.



Sure you're improving resolution! You can increase resolution by either making a smaller MAF look larger or by making a larger MAF look smaller. Let's say that you are using a 90mm Cobra MAF. At your peak horsepower you only generate 3.5volts. You are wasting 1.5volts of resolution. If you scale the 0-3.5volts to 0-5 volts, then recalibrate your PCM for a smaller MAF, your are effectively using the whole MAF's range.

Ben ---'96 Contour GL * Zetec ATX * Tan on Black steelies--- +++JRSC M62 Under Construction+++ My big-a$$ mod list.