Dual External Fuel Pump Plumbing for 4400?

[Bebop]

didn't read the whole thread. my setup is 2 internal Bosch 044s ran one at a time for redundancy for a stock bottom end, heads & cam LS3. just socks on the pumps no hydramat or one way pickups. each pump has an external check valves mounted to the outlet. they Y together to one line outside the cell, through a fragola filter, then to the ball valve on top of the cell and out to the regulator (AEM 13101). Vent is a -16AN rollover valve from Harmon racing cells, 1" heater hose routed 3 sides and down. works OK with my dump can. fills fast enough for me. my cell is big enough that I usually don't have to pit for our races.

it works really well. each pump has it's own breaker (no fuses) and it's own relay. the relay coils are both powered by the 12v fuel pump signal from the pcm, and the pumps are switched electronically by grounding each relay coil separately through an on/off/on switch in the dash.

I've simulated fuel pump failure by removing a pin from the wiring connector with the engine running, waited until the engine began to lose fuel pressure, then switched on the other pump and it worked perfectly every time. never had a pump fail in a real world scenario but it's good to know the system works should a failure occur.

only change I would make is flow-through rails but I haven't experienced vapor lock yet with the factory dead head rails. my fuel lines are very well isolated from external heat.

That's a great setup, thanks for sharing !!

What ECM do you use ? If it's a programmable unit, you could implement some more advanced pump control with a fuel pressure feedback and automatic switching between the 2 pumps during the race.

 

[G23crawler]

I'm not sure if you found your answer or not, there was a lot going on in this thread lol. Here is the system that came in my U4 car, its been racing for last 8 years and has worked fine. Dual intank, all ran off Spod. First pump is automatic with ignition button, second one on its own switch.
Im redoing my car before KOH with bigger cell. Going with dual external now, same wiring but plumbing is alittle different. One big pick up vs two pickups on the last setup.

 

[cdemart2]

That's a great setup, thanks for sharing !!

What ECM do you use ? If it's a programmable unit, you could implement some more advanced pump control with a fuel pressure feedback and automatic switching between the 2 pumps during the race.

Just a factory GM E38. None of these fancy new standalone PCM's were around when I built this car but it's great to see how far the technology had come and how obtainable it is. I really like the ecumaster system for what we do

 

[mobil1syn]

be careful with the switch that is on its own power source with no connection to the ignition.

also consider two fuel filters, if one gets clogged switching to the second pump
does nothing for you.

 

[cdemart2]

be careful with the switch that is on its own power source with no connection to the ignition.

also consider two fuel filters, if one gets clogged switching to the second pump
does nothing for you.

good call with the filter. maybe I'll add a 2nd.

I've seen bad things happen in crashes with fuel pump relays on their own power source. I always let the pcm power those relays. gm did that for good reasons.