Let's talk about fuel delivery and what not

4ward · Aug 2, 2003

Alright folks, I'm building my own fuel cell and have some questions.

1- I won't be running an internal fuel pump, so what fuel pressure/ flow am I going to need to look for in a aftermarket pump?

2- Why is the canister there? I'm not an engine person, never have been. I can fix them if it's something external, but I've never really gotten into the mechanics of how this system and that system works. Can I get rid of this thing? I don't need to worry about emissions crap.

I had another question, but can't think of it. This'll get the ball rolling though.

Sean

RCP Phx · Aug 2, 2003

First off you cant build a fuel cell.You can build the "can" that one goes in!

Kaczman · Aug 2, 2003

I just moved the stock pump to the outside of the cell--seems to work fine. I believe a F-150 frame mounted pump will work as well (ES2000?) The canister is for the tank vent. You can run the cell vent to it or ditch it if you aren't worried about keeping it emission legal.
-Jon

THE_OWL · Aug 2, 2003

Fuel Pressure wont be an issue. Thats what your fuel pressure regulator does. As soon as you system reaches the right pressure, the rest is sent back down the return. flow will depend on any mods.
Fuel pumps mounted outside of the tank have about half the life of in-tank. Fuel is cool, and when you prime your pump each time you start it, your pump will have to run dry until fuel reaches it. Like a Motor with no oil (think pre-oiler).
I just did a fuel lpump upgrade about a year ago, and the Hot rod shop guy told me he has great luck with the holley stuff, if its mounted in tank, outside, they dont last for more than a year.

xjjunkie · Aug 2, 2003

the stock pump is 45 gph @ 90/110 psi, there are many pumps out there to meet your needs. i sell one made by hypertech. it has 3/8 in/out, 12-volt, $128.50

scot

RNMedic · Aug 2, 2003

I would keep the in tank for for durability and just have access to the top of the cell to allow easy changes, then possibly use the stock XJ one. Reliable!!!

Jump This · Aug 2, 2003

90 to 110psi fuel pressure??? Wow....didn't think they ran nearly that high.... I have always used Holley or Redline pumps when running exsternal systems. Keep them close to your can and under or at least low compared to your fuel cell.

4ward · Aug 2, 2003

I won't be putting the pump in the tank, that's why I'm asking about external aftermarket pumps. Reliability isn't an issue on a vehicle that gets driven 10 times a year.

As I understand it, I can have a fuel line outlet, a return line outlet, rollover valve / vent outlet, and fuel fill. I'm thinking I could plumb the return line into the same line as the rollover and eliminate on outlet.

The reason to keep the pump low is to keep it from having to dry prime I'd assume.

Kaczman · Aug 2, 2003

Actually, the pump should be below the the tank due to the fact the pumps are better at pushing fuel than pulling suction. Mine sat for months with no fuel in the tank, but the line still had fuel from the cell to the pump...priming shouldn't be a concern.

I'd keep the return and vent lines seperate. The return flows a fair amount of fuel, and I would worry about gasoline being pushed through the vent. Also, be sure to install a roll over valve on the vent line.

As far as reliability is concerned, many of the Jeepspeed racers run the stock Bosch pump outside of their cells without problems. I doubt I'll use as much fuel in an entire season as they do in one race. I do carry a spare pump just in case....
-Jon

THE_OWL · Aug 3, 2003

I think Stock 4.0l engines require 45psi
My LT1 runs around 40psi, and my Big Custom Fuel Injected Chevy in the Jeep runs at a whopping 42. The pressure listed by Manufacturers doesnt matter. If you motor is gonna be modified with head/cam/stroke, then get an adj FPR
Priming will be an issue. OneTonXJ , you dont seem like the kinda builder who would say: "Reliability isn't an issue"

would you say that about an axle?

ChEwBaCcA · Aug 3, 2003

I think what OneSpun was trying to say is it doesnt have to have a long life span........ If they last one year outside the tank on a hot rod that gets 5K miles a year on it, it will last him 20 years since its only being driven 10X a year, started once, twice, three times that day X 10 days a year , follow? ..... makes sense to me

Chewy

THE_OWL · Aug 3, 2003

you could say the same thing about a radiator, when it fails, your getting towed.
follow?

XJEEPER04 · Aug 3, 2003

If he is only running the jeep 10x a year then the will most likely never have to replace his external. hell if he is set on running a external then let him...at least you can say i told you so if it does break (if)

Bender · Aug 3, 2003

For some reason I seem to recall someone posting the part number on POR about a month ago for a VW external fuel pump with just about the exact specs of the XJ pump.

Something like a max pressure of 90 psi and a flow rate of 45-50 gph??

FLXNXJ Wrote

"Well I changed my mind Whille the E2000 pump works, It doesnt pump as much as a stock XJ pump, I used a pump out of an late model VW beetle.
Jeep 92 XJ pump G.P.M. 45 psi. Max shut off 90 - 110 psi.
Ford E2000 G.M.P. 30-40 psi. max shut off 70-95 psi
VW E8305 G.M.P. 45 psi. Max shut off 100-110 psi.

I figure the closer to stock the better"

Here's the thread.
http://www.pirate4x4.com/forum/showthread.php?threadid=125162&highlight=vw+fuel+pump

4ward · Aug 3, 2003

Alright, for those of you that can't read- I'M USING AN EXTERNAL PUMP These pumps run for 100's of thousands of hours over many years. How can reliability be an issue for one that's only going to get used for 200 hours a year?

Bender, excellent tech I appreciate it very much. If it's $80 retail, I can get it for $60ish, which fits my pocketbook just fine.

Now back to fuel cell questions. Can the return line be plumbed into the top of the tank or does it need to go towards the bottom? I can't see where it matters since it's only refilling the tank.

XJJPR · Aug 3, 2003

OneTonXJ said:
Now back to fuel cell questions. Can the return line be plumbed into the top of the tank or does it need to go towards the bottom? I can't see where it matters since it's only refilling the tank.

Yes.

mark
orgs mfg

Bones · Aug 3, 2003

Yes.

Well said Mark

Bones :skull1:

THE_OWL · Aug 3, 2003

Alright, for those of you that can't read- I'M USING AN EXTERNAL PUMP

If you want to get the ball rolling, cool. If youre gonna cry about the responses, good luck.
Ill skip your posts I guess

4ward · Aug 3, 2003

If youre gonna cry about the responses

Maybe you should heed your own advice?

If you can't answer the question, I really don't care if you read my posts :rattle:

Mark, was that a yes or a yes?

Was checking out the canister this morning, it's definately getting pitched. The only other tube that hooks to it is going into the airtube. I'll just plug the hole in the airtube and call it good.

Beezil · Aug 3, 2003

The problem in naxja tech lately, is there are some good jeep builders and fabbers who know enough, or have already gathered enough info to complete 95% of their project, but they only need help with a small piece of the puzzle, yet when they ask their questions, some folks come along and try to deconstruct thier entire process.......

Let's talk about fuel delivery and what not

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