I'm planning for an auto conversion with EFI that requires around 45 PSI to the engine-attached pump and I'm wondering what is typically done in terms of redundancy. With the bottom of the wing tanks at the same level as the bottom of the fuselage, there's no way to gravity feed into a common header so it's a bit awkward.
The current plan is to use dual transfer pumps (Facet piezoelectric or similar) to push fuel from the left or right tank into a small header tank, and then two in-header auto pumps to get to the 45 PSI.
The header would initially have air that would need to be purged, so I've added a small orifice to return air/fuel to the source wing tank via the duplex valve. Each pump has a check valve to prevent backflow when only one pump per pair is on. All pumps would be on during takeoff/landing.
There is also an orifice at the output of the header pumps to prevent over-pressure from the EFI rail after engine shutdown.
Takeoff/landing power draw with all pumps would be about 8 A and half that at cruise.
Am I over-complicating this too much, or have others done similar configurations? Is there an in-line 45 PSI pump that can pull 12"+ that won't require a large amount of circulating fuel and current draw? Getting rid of the transfer pumps would be ideal.
The current plan is to use dual transfer pumps (Facet piezoelectric or similar) to push fuel from the left or right tank into a small header tank, and then two in-header auto pumps to get to the 45 PSI.
The header would initially have air that would need to be purged, so I've added a small orifice to return air/fuel to the source wing tank via the duplex valve. Each pump has a check valve to prevent backflow when only one pump per pair is on. All pumps would be on during takeoff/landing.
There is also an orifice at the output of the header pumps to prevent over-pressure from the EFI rail after engine shutdown.
Takeoff/landing power draw with all pumps would be about 8 A and half that at cruise.
Am I over-complicating this too much, or have others done similar configurations? Is there an in-line 45 PSI pump that can pull 12"+ that won't require a large amount of circulating fuel and current draw? Getting rid of the transfer pumps would be ideal.