Bosch MAF for VAF

[bjanesi at juno.com]

Thanks for the input John-

I think the problem is not so much knowing the flow, as it is correctly
adjusting the hot-wire voltage output over a range of flow conditions to
match what is normally delivered to the PCM by the stock VAF meter. 
Monitoring via an air-fuel (O2 sensor) meter, is probably a better way to
correctly adjust this, but I suspect a single static adjustment will only
provide a match at one flow setting, and not the entire range (but I
don't yet have any specific data to back up that statement).   

FWIW, I do have an extra pressure transducer pulled from an APC-equipped
Saab turbo.  What year is your 900?

Brad Anesi
-----------------------------------------
Date: Sat, 11 Sep 1999 09:35:41 -0700
From: "John Dammeyer" <johnd at autoartisans.com>
Subject: Measuring MAF

Hi,

I'll put in my two cents here.    Don't know how clever you are with
electronics
but if you purchase a differential pressure transducer you can build a
simple
flow meter by measuring the difference in pressure at two points.  Create
a
supply tube that has a restriction and measure the pressure at the
restriction
and the point before the restriction.  (venturi in effect).  As long as
you
know the temperature of the air flow and the size of the tubes you can
calculate
the airflow.  Then,  just use a DC powered fan with a variable power
supply to
push air through this pipe into the MAF sensor.

Alternatively,  you might be able to rent a hot wire anemometer from an
air
conditioning firm and if you place that in the air stream of your air
supply you
can also calibrate the MAF sensor.  I'm willing to bet that once you get
a few
accurate set points you can probably extrapolate the entire curve.

BTW.  Thanks for the info on the SAAB.  I have a 900 Turbo.

Regards,

John
___________________________________________________________________
Get the Internet just the way you want it.
Free software, free e-mail, and free Internet access for a month!
Try Juno Web: http://dl.www.juno.com/dynoget/tagj.