Converting vane type airflow meter to MAF

xxalexx at ix.netcom.com xxalexx at ix.netcom.com
Wed Jan 20 16:13:26 GMT 1999


> I just joined this list a couple days ago so I applogize if this is a 
> repeat question.  I am trying to determine the feasibility of 
> converting the vane type airflow meter in my 88 BMW 535i to a MAF 
> system.  My main reasons for doing this are the increased airflow to 
> the engine (more HP) and the reliability (no moving parts).  My 
> questions are:
> 
> 1) Are my assumptions above correct?
> 
> 2) How difficult is this conversion to do?  I am an embedded systems 
>    programmer so the software isn't really a problem.  What I really 
>    need to know is how complex is the conversion algorithm?  Do I 
>    need to add a MAP or a trottle position sensor?
> 
> 3) Are there any books you can recommend for this type of project?
> 
> 4) Is there is good "hobbyist" MAF out there that will fit well to 
>    this engine (3.5l ~6600 RPM ~220 HP).  I can deal with voltage or 
>    pulse output.  I was thinking of using a sensor from a 5.0 l
>    Mustang since it would be easy to find a replacement if necessary.
> 
> Thanks.
I did a simple intercept box using a PIC16C73 and a op-amp.
Used voltage divider to drop 10V vane output to PIC A/D modified
voltage in code using RAM interpolation  and outputed 10bit PWM to 
gain 2 intergration amp. Was designed for O2 sensor feedback.
There are some Asian kits to eleminate also.
alex  



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