Doug, this is what it looks like. I'll try to get into the manual to find
 out the pin-out functions.
 C. Smith



 Thanks.  Some air appears to have to flow through the device adding to
 restriction or enlargement of the manifold.  What size is it?  Do you
 have an idea where it was place in the system?  I am guessing the air
 box.

 Doug in Japan


Doug,
On the fords, they are mounted in a 75mm dia plastic tube with the air
filter on the inlet side. That is for a 220 to 285hp engine series.
For the rotary, make a 70 to 75mm tube with a fabricated flange to mount the
air flow sensor. that will size it for up to 300 hp. Above that we go to the
Lightning 90mm body with the same sensor.
The 90mm lightning sensor body is good for 525 hp before it is maxed out.
It is better to be a little on the big side than small. When tuning we never
want the sensor output to be over 4.5 volts. the sensor "rails" at around
4.75 or 4.8 volts, and then just flows more air without telling the computer
you need more fuel.

Mount the tube on the inlet of the air box feeding the tuned inlet tubes.
ideal size for the box should be at least 4X the volume of the combined
tuned tubes, and more is better due to the strong pulsing.

Let me know if you need a model or drawing of the setup, as I have a
lightning unit on the shelf that I can measure and draw up.
I need to get together with Paul so he can publish a good "do and don't do"
list for using the ford maf sensors. used correctly, they are great. set up
wrong..... things go lean and ugly in a hurry. been there.
Larry

Larry,

Thanks. I'll be in your neck of the woods in early June replacing the
starter motor on my other bird.  So I may be able to drop by if you have
time for lunch. As my rotary engine could very well be over 300 hp
occassionally I think using the larger Lightning MAF 90mm is a good
idea. A picture of the device would help as I know you are a busy guy.
Yes I agree on the air box size info.  Shape is also important I'm
told.  The  racers here often use a large tube with hemi spherical end
caps.  The 20B was boosted so the box was smaller but shaped the same.
Air like water takes the path of least resistance the only way to
confirm the airflow is balanced in the manifold is to flow test them.

I am still not exactly clear on  how to create the engine fueling map
when an engine is boosted.  I'm using the MegaSquirt device which
allows for custom formulae to create fueling tables. I am guessing I
would still have to sample MAP or actually deck pressure to tweak  the
MAF sensor data which calculates flow based on known tube diameter,
temp, and air speed. Perhaps having both sensors nearby each other would
be the best of both worlds.

Doug