mrjezza
05-11-2006, 11:33 AM
Has anyone done this conversion?
As I understand it the easiest way to make this work with an M42 would be to create some sort of circuit that converts the outpot of the M44's MAF sensor to match the output of the M42 AFM's variable resistor that is actuated by the flap.
How exactly would one calibrate the circuit? It would be easy to match up the reistances so that the resistance of the MAF with no air passing across it matches the resistance of the AFM in the closed position, but how would you calibrate the MAF to match the fully open position? Seeing as theres no restriction on the MAF as to a max position, just the limit of how much air you can make flow across the sensor wire, how do you know how much air actually equals the airflow in the fully open position? (Also, even if you can ascertain this figure by playing the MAF inline with your intake and recording the resistance on WOT, this may not even match up as the airflow should theoretically be better with the MAF than fully open on the AFM making the figure you recieve useless).
Could anyone speculate as to the likely performance gains (or aural gains) this conversion would see? Also, what's likely to go wrong if you don't end up matching up the outputs accurately - the car will run rich/lean?
As I understand it the easiest way to make this work with an M42 would be to create some sort of circuit that converts the outpot of the M44's MAF sensor to match the output of the M42 AFM's variable resistor that is actuated by the flap.
How exactly would one calibrate the circuit? It would be easy to match up the reistances so that the resistance of the MAF with no air passing across it matches the resistance of the AFM in the closed position, but how would you calibrate the MAF to match the fully open position? Seeing as theres no restriction on the MAF as to a max position, just the limit of how much air you can make flow across the sensor wire, how do you know how much air actually equals the airflow in the fully open position? (Also, even if you can ascertain this figure by playing the MAF inline with your intake and recording the resistance on WOT, this may not even match up as the airflow should theoretically be better with the MAF than fully open on the AFM making the figure you recieve useless).
Could anyone speculate as to the likely performance gains (or aural gains) this conversion would see? Also, what's likely to go wrong if you don't end up matching up the outputs accurately - the car will run rich/lean?