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What's needed to install a fuel cell?

33K views 6 replies 3 participants last post by  SHIFTY4 
#1 ·
With my planned suspension upgrades it looks like I may need a fuel cell also. I have never had a car with a fuel cell, so this is new to me. I have a 1970 Nova with a carbed SBC, mechanical fuel pump and stock gas tank. The car will be a weekend street car, that may see the strip once or twice a year.

What parts do I need to install a fuel cell?
What kind, size and shape cell should I get?
What features(line fittings, vents, filler, ect.) do I need to look for when selecting a cell?

I do have an electric fuel pump and regulator that came with the car, but its not running on those right now. Pretty sure its a Holley Blue or Red pump.

I already found a thread that had great pics on cutting the trunk floor for the sump and mounting the cell.
 
#2 ·
Fuel cell size should be one that you think that you will need. Obviously a 4 gallon fuel cell probably wont work for you. Now deciding what you need is going to determine on what you want. How much trunk space are you willing to give up verses what size cell do you want? Return fuel line? Operable sending unit? Fuel lin type. I agree that an area should and needs to be cut out for the sump. You also need to consider what type of fuel pump you want to run especially if you decide on an electrical pump, because location of the pump needs to be considered. Fule cells also need to be vented to the outside atmosphere. Are you planning on a custom fuel filler neck or do you intend to open your trunk everytime you want to fuel the car?
Jegs, Summit and the like sell basic braided fuel line and filter kits for this. Also they both have a large array of fuel cell types and and sizes to consider.
Since you want to drive this car on the street a fuel sending unit you may want so you know what fuel level you have.
This is just and idea of things to consider. But it get you in the right direction.
 
#3 ·
Jegs has a decent looking cell that includes a GM style sender. I'm thinking that something like a 16 gallon cell should be good, I don't plan to drive the car very far but i want to be able to go on a decent cruise without filling up every 30 minutes. I planned on just opening the trunk when I need to refill, thats not a hassel to me. I also don't mind giving up trunk space.

What are the reasons to go with a sumped cell instead of a flat bottom?

What do I need to consider to decide whether to run the mechanical fuel pump or an electric pump? What determines if I need a return line? Is that dependent on the electric pump and regulator?
The electric pump is already installed on my car, it just needs to be wired up and fule line run if I wanted to use it. I'd also need to install the regulator.
 
#4 ·
You will have to ground the fuel cell and vent it to the outside with a roll over valve in the vent line. The back of the trunk (behind the rear seat) and the package tray (which means no rear speaker opening unless boxed in) must be covered with either a steel (0.024") or aluminum (0.032") firewall. Any fuel lines going through the floor must use either a bulkhead fitting, or be protected with a sealing fire resistant grommet. The fuel return line should be as far from the pick-up and as deep into the fluid as can be practical to reduce aeration of the fuel.

What are the reasons to go with a sumped cell instead of a flat bottom?
The sump is the lowest place for the fluid to flow to. It will always be covered if there is fluid in the cell. You should be concerned with cavitation and turbulence at the pick-up point as you want gas and not vapor in the fuel line.

What do I need to consider to decide whether to run the mechanical fuel pump or an electric pump?
An electric fuel pump can be sized to move more fuel than the mechanical pump driven off of the eccentric on the cam (it only has a fixed amount of lift). A mechanical pump adds heat to the fuel making the fuel less dense, but easier to atomize (or vapor lock, if it is a hot day).

What determines if I need a return line? Is that dependent on the electric pump and regulator?
You always need a return line. It is something the factory cheaped out on when producing a car. Every fuel pump heats the fuel by compressing it. If it has to continually compress the same fuel inside the pump because it can not push the fuel out against a closed needle and seat it just goes into vapor lock (boils the fuel at 112° F). The bigger the pump in gph then the faster it boils the fuel. On the other hand if you have a return line the constant flow of fuel through the pump cools the pump (which makes an electric pump last longer).


The electric pump is already installed on my car, it just needs to be wired up and fule line run if I wanted to use it. I'd also need to install the regulator.

Yes you will need a return line fuel pressure regulator. Everyone talks about seven psi as the magic number. That is that absolute maximum pressure that the needle can exert on the seat. You want to be below that figure so you do not risk blowing the needle off the seat and flooding the engine with overflowing gasoline. I use 14 psi to the regulator from my Aeroquip electric fuel pump, which will overcome any fluid friction or forces of acceleration in my 9.30 second car. I drop the pressure down to only 4 psi at the entrance to the carb (a 1250 cfm Dominator with a 0.130" sized needle and seat).

Big Dave
 
#5 ·
Again with the great info Dave, thanks alot. I think most of my questions have been answered.

With the sump is there anything special you have to do to the hole in the bottom of the trunk? You stated that fuel lines going through the floor have to be fire sealed. Does this apply to the hole for the cell sump also?

I found pics in this thread showing a fuel cell install. Is this what I would want to follow to install the sumped cell? Looks pretty easy.

One more question, any reason to spend the extra money on an aluminum cell over plastic?
 
#6 ·
Again with the great info Dave, thanks alot. I think most of my questions have been answered.

With the sump is there anything special you have to do to the hole in the bottom of the trunk? You stated that fuel lines going through the floor have to be fire sealed. Does this apply to the hole for the cell sump also?

I found pics in this thread showing a fuel cell install. Is this what I would want to follow to install the sumped cell? Looks pretty easy.

One more question, any reason to spend the extra money on an aluminum cell over plastic?
The sump is below the tank and is covered by it. If you have an aluminum tank it qualifies as a part of the firewall.

A grounded aluminum pump won't spark with static electricity while being filled (can not say that about a plastic tank). Aluminum tanks have welded in baffles. Plastic tanks have baffles that were rolled up and then dropped through the top to expand again, but they just slosh back and forth in the tank as they are not attached to the sides.

Big Dave
 
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