Calibrating MAF

[Jeff Webb]

Mark Atkinson wrote:
> 
> Ben Beacock wrote:
> > Anyways..   does anyone have any clever ways that I could calibrate the
> > stock vane airflow sensor?  With a pressure guage and some sort of velocity
> > measurement?
>
> Yes make up an ASME orifice plate and put a manometer across it, place
> this in series the MAF unit and read pressure differential across the
> orifice plate, vs voltage on the maf sensor. Then compare the pressure
> to the flow for that type of orifice (there are tables available for
> ASME orifices pressure vs flow) Take readings at several different
> flows, make sure that the intake temperature is noted and if you are
> significantly above sea level, correct for the barometric pressure also.
> I hope it doesn't sound too complex, it is really a simple process, the
> only problem may be getting the higher flows, vacuuum cleaner blowers
> are only good to about 40 cfm, and indistrial pressure blowers tend to
> be expensive. An engine can be used as a blower to give the range of
> flows, but under no load it doesn't really flow much more than the
> vacuum cleaner blower!

If anyone goes through the trouble to build such a setup, it would be
good to have people send in a wide range of MAF/VAF sensors for
testing.  After all, once you've got the test rig, calibrating more
sensors would be very little work.  I think building up a database with
this sort of information would be of immeasurable value to the group. 
I'm sure there are lots of people who have MAF sensors they could lone
for testing, and they would probably be willing to chip in a little cash
to help a guy pay for the equipment and labor to get this thing done.

I was thinking about doing something similar with MAP sensors.  I'm sure
there are lots of other sensors we could do as well.  They key would be
to make sure the testing is done properly, and that we get plenty of
data.

Surely, there are people on the EFI332 or DIY lists that have access to,
or would be willing to build such test rigs.  This is just an idea for
those who want to contribute, but haven't found an avenue, so far.

Jeff Webb
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