Started working on the fuel selector valve, AFP fuel pump package from Vans on my RV7A, with ECI 360FI engine, AFP fuel injection, mechanical pump and have a few questions. The AFP electric fuel pump package is mounted in the housing (provided by Vans) in the cabin.
I have an Andair 6 port fuel selector valve with #6 AN supply fittings (adapted to 1/4" pipe fitting at the valve) #4 AN return fittings (adapted to 1/8" pipe fittings at the valve).
1. The standard AFP fuel pump package from Vans provides for a return line from the pressure regulator to the fuel supply line (from the fuel selector valve). This effectively creates a loop relieving the excess pressure generated by the electric pump. It seems that looping the fuel back through the filter and pump would heat the fuel, but if I read the previous threads on that subject, the additional heat created is not an issue.
2. As an alternative to the standard package, I could route the return from the pressure regulator to the return line input on the Andair 6 way valve (1/8" pipe, #4 AN fitting) and the fuel would be returned to the tank it came from. This should reduce the heating of the fuel when it is returned to the tank again. It does however require reducing the fitting on the pressure regulator from 6 AN to 4 AN. The fittings are available through JEGS. Would restricting the output from 6AN to 4AN create a new problem?
The alternative method (Item 2.) would require joining the AFP fuel injection purge valve return line to the return line from the pressure regulator and then routing to the Andair valve return line input. I don't see any issues here because the purge valve is a mechanical valve (either on or off).
I am leaning toward the alternative method because of the fuel cooling effect. Suggestions and comments appreciated.
Thanks,
Don
RV-7A
ECI O-360 FI
Finishing fuselage
I have an Andair 6 port fuel selector valve with #6 AN supply fittings (adapted to 1/4" pipe fitting at the valve) #4 AN return fittings (adapted to 1/8" pipe fittings at the valve).
1. The standard AFP fuel pump package from Vans provides for a return line from the pressure regulator to the fuel supply line (from the fuel selector valve). This effectively creates a loop relieving the excess pressure generated by the electric pump. It seems that looping the fuel back through the filter and pump would heat the fuel, but if I read the previous threads on that subject, the additional heat created is not an issue.
2. As an alternative to the standard package, I could route the return from the pressure regulator to the return line input on the Andair 6 way valve (1/8" pipe, #4 AN fitting) and the fuel would be returned to the tank it came from. This should reduce the heating of the fuel when it is returned to the tank again. It does however require reducing the fitting on the pressure regulator from 6 AN to 4 AN. The fittings are available through JEGS. Would restricting the output from 6AN to 4AN create a new problem?
The alternative method (Item 2.) would require joining the AFP fuel injection purge valve return line to the return line from the pressure regulator and then routing to the Andair valve return line input. I don't see any issues here because the purge valve is a mechanical valve (either on or off).
I am leaning toward the alternative method because of the fuel cooling effect. Suggestions and comments appreciated.
Thanks,
Don
RV-7A
ECI O-360 FI
Finishing fuselage
