Bosch to Hitachi Maf

[Terry McLane 312.630.0533]

    Thanks for the advice on how to invert the signal.  The second part of 
    my question related to some type of manual adjustment of the signal.  
    In otherwords, the existing bosch MAF is setup to be wide open (0 
    volts) at engine peak torque (3200).  It may flow about 220 CFM at this 
    point.  On the other hand, the Hitachi MAF may be able to flow 500 CFM, 
    so a way needs to be found to adjust the voltage signal (besides 
    inverting it), that the ECU would see.  Assume that we have measured 
    the voltage output of both units at 10 and 220 CFM (assume air 
    temperature is equal).  The Bosch puts out 4.7v at 10, and .3 volts at 
    220 CFM.  On the other hand, the Hitachi puts out .5v at 10 CFM and 
    3.6v at 220.  I'd like to have a programmable device that could convert 
    the two, interpolating the voltage signals between the actual measured 
    values (in this example, only two).  Now that I've explained the 
    situation better, perhaps there is a single solution to both the 
    inversion and interpolation.  Ideally, a black box which mates to the 
    Hitachi MAF, and has a few dials one for each CFM level (actually MASS 
    AIR level) allowing a user to specify the output reference voltage at 
    each mass level, with the box interpolating between these. This type of 
    device would allow you to use the excellent Hitachi MAF in place of 
    most other MAF sensors.  Anyone want to productize this and make some 
    money?  
    
    Terry McLane tm8 at ntrs.com