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


Larry,

I found it on E-Bay.
http://tinyurl.com/o6na5k

Doug


Here are some more, I think the 90mm is a bit less expensive here.

http://www.blueovalindustries.com/products.php?catID=9902232

C. Smith


Larry or Craig,

I am probably going to order the 90mm diameter MAF sensor as it has less
restriction than the 61mm unit.  Do either of you know how to calibrate
it or does it come calibrated assuming it will be used  flowing into an
Ford airbox?


Thanks

Doug

Doug and Paul,
Megasquit has some good info on MAF. It specifically has data on
the 'Ford MAF' and the 'Nissan Inifnti Q45 MAF' Sensors.
"http://www.microsquirt.info/mafmap.htm"

I am still here,
Blake

I converted mg/sec to pounds per minute which is more common
form in most of the old books on engines.

Switching to the metric system is a nightmare because of this.

-------------------------------------------------------

At 70 degrees F and 14.696 psia, dry air has a density of 0.074887 lbm/ft3.

So I used that number to add to the Ford MAF chart.
We have a lot more CFM data on engines than anything else.

Paul Lamar

Paul,

Good stuff, thanks.  These calculations get me close enough that I can
establish a base line for comparative testing.  Tomorrow and Friday are
shop days so I am whipping up a 12mm thick 55mm dia. butterfly throttle
and P. port insert for flow testing. The 5mm axis  is on the horizontal.
I will order the plate laser cut and am thinking of leaving a small 2mm
ellipse cut out on top of the throttle plate.  Enough that the flow is
just under idling speed.

Blake thanks a bunch.  Gee I thought I had read everything about
MegaSquirt but obviously not.  Printed out all of the info on and about
Megasquirt methods and application and case studies would fill a small
book.  This device has become the LINUX of the engine tuners universe.
I was very happy to find the mention of a Nissan 80mm dia. low
restriction MAF sensor as well.  I'll try the local junk yard to see if
I can pick one up over here before I send a way for the FORD unit..

Doug in Japan.

I was rather surprised that the voltage output was not a linear function
of mass airflow.

BTW can any of you spread sheet gurus convert this xls plot to voltage as a function
of mass airflow in terms of pounds per minute?

Also it appears the Ford V8 MAF sensor shown on mega squirt is too large for a 250 HP Rotary.
The V6 75 mm is the hot tip as Larry says. What is the ID of the V8 Larry?

Paul Lamar