Any issues running duel fuel pumps?

[Jeff_oddo]

I recently had a triple pump return style fuel system installed and was wondering if anyone has heard of short and long term issues running a duel fuel pump setup with the 3rd triggered with a Hobbs switch? I initially was running the 3 pumps all the time and yesterday had the Fore Honeywell 5psi Hobbs switch installed. I know running 3 pumps all the time was a little overkill and I'm sure the excessive heat was not good and that's why I installed the Hobbs switch. So my question is now that I'm running dual Walbro 465 pumps is there any issues I might encounter? Thanks for your help.

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[phunk]

You dont have enough fuel injector to need 3 of those pumps. Why dont you just disconnect one of them entirely? Run the single full time, and the aux on your Hobbs switch. Or, if you really want to have 2 running all the time, just forget the Hobbs switch and the 3rd pump. Theres no point to it.

 

[Jeff_oddo]

You dont have enough fuel injector to need 3 of those pumps. Why dont you just disconnect one of them entirely? Run the single full time, and the aux on your Hobbs switch. Or, if you really want to have 2 running all the time, just forget the Hobbs switch and the 3rd pump. Theres no point to it.

Well... I will be going E85 shortly and plan on making more power. Decided to do the 3 pump setup since I don't want to do a fuel system twice. Right now the 3rd pump is off the Hobbs switch.

 

[phunk]

Well... I will be going E85 shortly and plan on making more power. Decided to do the 3 pump setup since I don't want to do a fuel system twice. Right now the 3rd pump is off the Hobbs switch.

You still wont need the 3rd pump. Unless you build your engine and get significantly larger fuel injectors, you will never need the 3rd pump.

Assume your differential fuel pressure is 55psi like Lund uses.

ID1000 @55psi and 14v flows 1055cc/min according to IDs chart.

1055cc x 8 injectors = 8440cc/min max fuel flow you have with your injectors.

8440cc/min = 506lph.

Even at 80psi rail pressure those pumps move 325 LPH each, 650lph combined. At a more realistic operating pressure youve got more than 700lph from a pair.

You will be over 1000hp by the time you need that 3rd pump.

 

[Jeff_oddo]

Oh well.... not taking the 3rd pump out. I'll have all the fuel I'll ever need then

 

[beefcake]

I would trigger 2 on the hobbs

 

[phunk]

Oh well.... not taking the 3rd pump out. I'll have all the fuel I'll ever need then

I hear ya, I wouldnt take it out either. I just wouldnt bother turning it on. I would keep it in there as a backup. If you cant bring yourself to do that, I would do as beefcake suggests, and wire both aux pumps to the Hobbs switch. 700+ LPH of fuel at idle is a bit overboard.

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