It is sometimes difficult to mount fuel pumps in AC wings.
Most people don't do it. They mount the pumps on the firewall.

Paul Lamar

Paul,

I'm just starting construction of my fuel tanks for a Zenith CH-640.
I'm opting for a four wing tank system. I'll likely be using a 16b
conversion, fuel injection based on your designs. With the discussion
on-going
 about
in tank fuel pumps and fuel return lines, I am asking if I need to make
accomodation for anything special. Presently, my tanks have no
 provision for
a fuel return or in tank pump. Would it be necessary to design in any
 of this stuff?

Thanks, C. Smith

Yes you might think of adding a large removable panel in the root ribs for
internal pumps. The 640 has a nice thick wing for internal pumps. Looks like
the tanks are in the leading edge. If not practical use two lines from each
tank. One for feed according to the plans and one for return fuel.

Paul Lamar

Correction, I meant 13b engine.
C. Smith--


 So the EFI system with a fuel return line would preclude the use of a
 fuel flow meter to keep track of fuel used and burn, unless someone
 knows of a meter that subtracts the return flow?
 so with a 4 tank system, thats 8 fuel lines, and a tank selector valve
 ganged 4x4? 4 separate fuel pumps, and control wiring?
 No other way to do this? I'm bummin' out.

 C Smith


C,
There are systems that will subtract the fuel return, but dont bother.
Here is what I recommend.It is what I did an I find it works very well.

Route your SINGLE return line to a tank you consider your 'main' tank.
Not a header, but your largest tank.The fuel valve now has to select only
which tank you are drawing from, but you will obviously be using your main
tank most of the time.When you select one of the other tanks, the fuel then
is in essence being transferred to the main tank.
That is OK.Will transfer at a known rate of about a gallon/min.It is
imperative that you set some sort of alarm to avoid overflowing the main
tank.I actually have a fuel flow transducer on my RETURN line, and I set it
to remind me after I have transferred the desired number of gallons to the
main tank.

This is simple and reliable.Only one simple return line, simple fuel select
valve, and only necessitates an alarm for when using one of the other tanks.

As a fuel totalizer, use something that tallies the injector workload such
as Ed Anderson's EFI monitor or Tracy Crooks EM2.I have Ed's and it does a
very accurate job of keeping track of the fuel.

JMHO
--
David Leonard

Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net

I think I will build this simple circuit on to the 555 injector PC board.
All you will need is a digital voltmeter for read out of GPH.

Paul Lamar

Great discussion friends. Paul, I'm going to try to duplicate your set-up
with the simple volt meter, could you send me a link with the digikey part
you decide to use? I'm thinking that the same digital output can be fed to a
small programmable device like a digital stamp, write a simple program to
sample and reformat it to send out in efis required formats. Give me a
project to work on.
What was the Ford specific information some folks wanted? I'm right next
door to the Fuel Systems lab, maybe I can get the info you need from the
guys who design it.


Thanks for all of your ideas, they are very helpful.
C. Smith


You will need to experiment a bit on the resistor and
the capacitor values to get the time constant such that it does
not saturate.
http://www.electronics-lab.com/projects/test/014/
http://parts.digikey.com/1/parts-kws/digital-voltmeter
Use a hand held VOM to get started.

Paul Lamar