Triple Pump Staging

[larry_g]

So I'm finally pulling the trigger on upgrading my fuel system to a triple pump setup. It's more fuel than I need right now, even with a smaller pulley and the occasional tank of E85, but I only want to do this once. I'm on my own for powering the pumps and have been tossing around a few ideas, from off-the-shelf (like Fore FC3) to complete DIY so I'm looking for a little input.

In my research (https://www.enginelabs.com/engine-te...-deatschwerks/) they actually ran two pumps full time as the primary with the third pump triggered by a boost switch. The argument being that if one of the primary pumps fails, the car is still drivable and, at least at my power level, not likely to go lean even under full throttle.

Any thoughts on why or why not that is a good idea, and how would you do it?

[dreksnot]

Many run 1 then have 2&3 power-on when 4-5psi Hobbs engages.

I've tried that, then I've tried 2 like you're mentioning, with 3 coming on with the 4-5psi Hobbs.

It really depends on your expectations. I researched if 2 always-on would create too much heat. I don't think so. I'm still pondering to continue to run just 1 but I did notice that if I get into it, I start getting close to maxing the pump capacity "while" waiting for the other 2 to power on (takes approx 0.4-0.5secs). Could be dangerous.

That all probably didn't help any, did it.

[larry_g]

I daily mine so I kinda like the idea of redundancy being less likely to leave me stranded somewhere. It's probably what I'm going to do unless someone comes up with a really good argument as to why I shouldn't.

I guess if I build my own control I could always use one primary, the secondary on around 2-5 psi and then the third on over 8 psi. The downside is more potential points of failure.



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[Batmanntexas]

I run a triple setup on my Avalanche. One is always on, 2nd comes on @2psi, the 3rd @5psi.

[larry_g]

Originally Posted by Batmanntexas

I run a triple setup on my Avalanche. One is always on, 2nd comes on @2psi, the 3rd @5psi.

Did you build the control yourself?



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[blake-b]

You don't need a controller, you can wire in (2) different Hobbs switches (one for each pump to come on at different times). Or both pumps on one Hobbs switch so they come on at the same time.

I was running a dual pump set up (walbro 485s). Second pump came on at 1-2 psi and the second pump was also on a boost a pump. Zero issues at 1200whp.

My ZR1 has (2) auxilliary 044 pumps. One comes on at 8 psi, the 2nd comes on at 12psi.

[larry_g]

Correct me if I'm wrong, but you still need to run the Hobbs switches through relays, so you are effectively building your own control. Maybe not a packaged unit but you still have to handle power distribution and fused circuits to do it safely.

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[dreksnot]

Originally Posted by larry_g

Correct me if I'm wrong, but you still need to run the Hobbs switches through relays, so you are effectively building your own control. Maybe not a packaged unit but you still have to handle power distribution and fused circuits to do it safely.

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One switch Relay and one power relay per pump. One Hobbs on 2nd and 3rd pump. Easy.

[blake-b]

Yes, correct. I was envisioning the Fore controller (which is nice!) But you can replicate its function with relays and Hobbs switches much cheaper.

If you can find someone with Squash pump instructions, they would be helpful in making your own setup. They are dual pump but it would be simple to add another pump to the diagram.

[larry_g]

By the time I gather enough quality parts to do the job gracefully, I'm not far from the cost of the Fore. I don't mind paying a bit more for a proven solution, so I have an FC3 on order.

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[eLeSthree]

Ive heard running two pumps could cause too much heat and consume power that really isnt needed.

What size injector do you plan to run? If its a 1000cc or more it should have plenty of headroom to carry you for that split second until the other two pumps kick in. I set my adj boost switch to kick both pumps on at the first sign of boost. I will admit, i do have some transient fueling that is a little off but its not a big deal. Its a few percent for a split second.

[larry_g]

I'm currently running ID1050Xs and pretty sure they'll be fine with one pump until 5 psi, even on E85.

The only reason I like the idea of running two primary pumps is the redundancy and safety factor if any one of the three fails. I'm willing to tolerate some inefficiency as long as it isn't dangerous to me or the engine.

I'm still looking for a strong argument as to why I absolutely shouldn't run two primary pumps.

Parts are on the way, installation will probably start next weekend. Wiring the pumps is one of the last items and it's an easy change between the two setups, literally swapping the trigger wires at the module.

Either way, I won't put the rear seat and panels back in until after we're done on the dyno in case we need to make a change.



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[dreksnot]

I just swapped back to two pumps but running a lower fuel pressure. I noticed as I'd get into boost (and it builds quickly) that my FP would start to lower before #2 and #3 pumps kicked on.

[larry_g]

Originally Posted by dreksnot

I just swapped back to two pumps but running a lower fuel pressure. I noticed as I'd get into boost (and it builds quickly) that my FP would start to lower before #2 and #3 pumps kicked on.

Interesting, thanks.



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