Dual Tank Plumbing Advice and Considerations

It's just a suggestion for a pump that I like and that you can research. I don't have any applicable info you could relate to. Check the flow rate and compare to your needs.
 

Howard Jones

Supporter
I have a 450HP engine. I run it on track for 30 min sessions at Circuit of the Americas. Lap time at about 2:35 sec. I use right at 5 1/2 gals per session, and I would estimate that the car is full power for about 60% of a lap. For the remainder of the lap, I would guess it is making something like 50% of its full power. That comes out to about 5 miles per gal.

So what is the gal per hour requirement of my engine? Well, that's about 12 average right? Let's say 1/2 the lap it's about 24 gals per hour and 1/2 the lap it is about 6-8.

I have one of these in the car. As you can see it's way overkill at 70 gals per hour.


Why is this important for you? When the car is in use the WAY you are using it will drastically influence the fuel usage and thus the gals per min. If you are going to build a street-only car it will more than likely only make 10-25% of its total power 90% of the time and only full power maybe 1% of its lifetime.

A 4 barrel car will recover from a short blast of full power back to cruise speed (on-ramp blast) and never use all the fuel in the carb float bowls given that they are being refilled by the fuel pump even if the pump cannot deliver the full power delivery rate. An FI system will need a pump system that can deliver a usage rate close to full power requirements but even then there is going to be a significant volume of fuel in the system to act as an accumulator to dampen spikes in fuel usage when the engine is near or at full power for short periods of time.

So as you look for electric pumps don't let bigger is better get to you. Any of the Holley pumps will work and if I need to replace my Mallory pump I will use a Holley or the Summit clone:



Same thing just not polished.

Here is a FI external pump that would suit a 60 GPM 70 PSI requirement. There are many choices in this range.


In my opinion, this is more than enough for a 450Hp engine. You will need a regulator that can flow 60 GPH@ 70 PSI and then a filter that can flow that much also and you are good to go.

Since Webber's work at a much lower pressure, you will need to accommodate that with a proper pressure regulator and be sure the pump will still flow at your required rate at that lower pressure, but the GPH figure still won't change.

Here is a couple of things on Webber pumps:





You might want to call these guys and ask about high powered Webber V8 setups:


Good luck
 
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I HAVE LOOKED AT SO MANY PUMPS . WAS ON THE PHONE WITH HOLLEY FOR AN HOUR. THEY TOLD ME NONE OF THEIR POMPS WILL LIFT FUEL . THE PROBLE HAS BEEN FINDING ONE THAT WILL LIFT FUEL AND THAT IS LOW PSI AND ENOUGH GPH
 

Neil

Supporter
Don't worry about a "low psi" fuel pump- just put a fuel pressure regulator after the fuel pump to reduce pressure for your Webers.
 

Davidmgbv8

Supporter
I just got my the first of my fuel system components yesterday but I forgot the regulator.
 
Never had a problem with 2x Facet red tops. Run on one pump on the road and run both when on the track. 302 with 340bhp.
Tank-filter- pump (down low)- non return valve- filter king--teepiece-pressure guage-Holley 670cfm.
 
Hi all,

Looking for advice, suggestions, schematics on how to plumb a 2 tank setup for an RCR40. I am planning to run the tanks independently with no crossover and feeding a quartet of Webers which are plumbed in series. There is no provision for fuel return, so will be plugging those holes in the tank.

I am using 2 separate fuel pumps, each controlled by an individual switch with the idea that the two lines would come together in a T then on to the carb setup.

Here are some questions:

1. The Facet fuel pumps have a built in filter screen. Should I use an additional filter? If so, what size and where? Should this be between the tank and the pump, or downstream of the pumps where the two tank lines T together?
2. What one-way check valves should I use to prevent one tank from pumping fuel into the other? Where should these be located?
3. I'd like to use Aero-quip style braided lines with the red/blue AN fittings. What gauge should all this plumbing be?

Anything else I haven't thought of or a diagram of someone's similar system is much appreciated!
Hello Pasha, I am trying to install the fuel tanks. I will use foam but don’t know what the syste, diagrams look like. I am hoping that you can help me. There are no 8nstructuons for this part of the build. There are three threaded holes in the tank. What’s hooking up to what? I hope that youve solved this. Jim
 
I just got my the first of my fuel system components yesterday but I forgot the regulator.
This is helpful David. I am just starting my RCR40 build and am putting in the tanks. Did you ever find a diagram and other parts? I see three threaded sockets on the tank. Obviously, one of them is to provide the fuel. Any help would be appreciated. jim
 
Hello Pasha,

You will most definitely need a separate fuel filter for each tank. My 5 litre 350hp GT40 has been running for 22 years with this setup:
Plumbing:
Tank---filter---Facet redtop---nonreturn valve--filter king filter/regulator--teepiece with fuel pressure guage port--Holley 670
Tank---filter---Facet redtop--nonreturn valve--filter king filter/regulator---

wiring:
switched 12v source (I use ignition switch)----dashboard left pumpswitch----30a relay coil--low oil pressure switch/earth
+12v----20a fuse----relay----left pump (mounted as low as possible)----earth

switched 12v source (I use ignition switch)----dashboard right pumpswitch---30a relay coil--
+12v----20a fuse----relay----right pump (mounted as low as possible)----earth

For track use, run both pumps. If the engine stops running, the pumps cut out.

Good luck, Tony.
 

Howard Jones

Supporter
Yes! The Mallory below will. Here's my setup. The pump inlet is right at the same level as the main bottom of the fuel tank. It draws fuel from the center top of the tank that is 10 inches higher than the bottom and then another 13/4 inch lower than that from a sump in the bottom of the fuel tank. That's 113/4" in the tank and another 2 inches higher as the fuel is drawn through the feed though fitting and the 90-degree hose end for a total lift of 133/4 inches.

Then the fuel flows through 50 inches of 1/2 inch Id hose, through the bulkhead, an inline filter, and then to the pump inlet. Everything from the top of the tank inlet hose is downhill in general but the filter is located vertically so the fuel makes a turn up to the top and flows down through the filter to the inlet to the pump.

The pump then delivers fuel to the regulator and then onto the carb inlet. I am using a return type regulator so the return line returns fuel to the top of the tank.

The last picture is the previous layout using a deadhead regulator but the general layout is the same now with the return type regulator.

 

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