# Fuel pressure setup for fuel cell



## Vodoo48 (Jan 8, 2004)

What I'm working on here is my 88 'rocco. it's a 2.0aba block with a 1.8 8v big valve cis head. I'm running just the stock cis setup. I'm switching over to a fuel cell instead of the stock gas tank. I was told I could keep the stock 2nd pump (under the car/frame rail) But now I need to know what pump i should run to replace the in-tank pump. I also told I could use a low-pressure high-volume pump similar to one used for a small block v8 engine. Does anyone know the pressure I should be running out of the fuel cell? and can I use a pump that i would mount next to the cell instead of in it?
Thanks for the help http://****************.com/smile/emthup.gif 








Thats the 'rocco it's going in (for clicks)


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## motorbreath1800 (Jan 11, 2008)

You need something that puts out around 60psi or so. So maybe 70LPH or so. If you call summit racing or jegs, you can talk to there tech dept and they could probably suggest something.


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## Vodoo48 (Jan 8, 2004)

*FV-QR*

Really? A vw tech at my local dealer told me it was a low pressure setup coming out of the tank and the one under the car was the high pressure pump. Are you sure it's 60psi?


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## jackfrost1031 (Oct 19, 2004)

*Re: FV-QR (Vodoo48)*

why can't you just adapt the stock pump and put it inside the fuel cell?
If you do a bottom drain fuel cell the high pressure pump ought to be sufficient. The Audi Coupe GT only has one pump and the fuel comes out of the bottom of the tank.


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## iamdagerman (Feb 19, 2006)

*Re: FV-QR (jackfrost1031)*

Just put a fuel nipple on the lower part of the fuel cell, so the pump feeds directly off the fuel cell


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## WackyWabbitRacer (Apr 24, 2001)

*Re: Fuel pressure setup for fuel cell (Vodoo48)*


_Quote, originally posted by *Vodoo48* »_What I'm working on here is my 88 'rocco. it's a 2.0aba block with a 1.8 8v big valve cis head. 

Is your fuel injection the basic CIS mechanical or the CIS Lambda? Both systems need a System Pressure of 68 to 78 psi at the fuel distributor.
The earlier (1978 to 1984) CIS fuel pump will be more adequate as it can create a "deadhead" fuel pressure of about 100 psi.
The problem with all of the CIS fuel pumps is that they are "suckers" of gas and not "pushers" of gas. Consequently with a fuel cell, a low pressure fuel pump, such as a Carter 4070, is needed to draw fuel out of the cell. 
Here is my diagram of the fuel cell setup in my old SCCA H-Production racer.








Cheers, WWR.


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## Vodoo48 (Jan 8, 2004)

*Re: Fuel pressure setup for fuel cell (WackyWabbitRacer)*

I am using CIS basic. So what you're saying is I can use a low pressure pump (4psi and 60-70gph) to pull the fuel from the tank and the second stock fuel pump will supply the high pressure needed to the engine. If that's the case than great, thank you. If not, then I don't understand at all, lol.


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## WackyWabbitRacer (Apr 24, 2001)

*Re: Fuel pressure setup for fuel cell (Vodoo48)*


_Quote, originally posted by *Vodoo48* »_I am using CIS basic. I can use a low pressure pump (4psi and 60-70gph) to pull the fuel from the tank and the second stock fuel pump will supply the high pressure needed to the engine. 

Yes, you need a low pressure fuel pump to draw the fuel from the cell.
Then to create the needed System Pressure, you need to use the CIS high pressure pump.
CELL ----->low pressure pump------->CIS high pressure pump---->FD
Cheers, WWR.


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## wclark (Mar 28, 2001)

*Re: Fuel pressure setup for fuel cell (Vodoo48)*

Think of the in-tank pump as a transfer pump because the main pump doesnt alwasy draw as well as it should. You just need to get fuel to the main pump in adequate quantity, it will produce the CIS required pressure.


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## Vodoo48 (Jan 8, 2004)

*FV-BumpIt(1241932954937)*

Still having issues. Do i need that fuel container between the pumps? I put it in my setup and I was only backfeeding fuel up the return. I bypassed it and the car starves for fuel... I'm pulling my hair out.


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## ABA Scirocco (May 30, 2001)

*Re: FV-BumpIt(1241932954937) (Vodoo48)*


_Quote, originally posted by *Vodoo48* »_Still having issues. Do i need that fuel container between the pumps?

Yes, it evens out the pulses in the low pressure pump and more importantly allows you to have a mismatch between the capacities of the two pumps without over-stressing either pump. Depending on how much of your original fuel delivery system is still in tact, your 88 Scirocco has (or had) such a container already, it's above and slightly behind the high pressure fuel pump, it looks like this. It has two inlet fitting and two outlet fittings and has a filter screen built into it. VW calls it a filter it's part #533 201 511A and costs just under $20.00












_Modified by ABA Scirocco at 6:50 AM 5-10-2009_


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## Vodoo48 (Jan 8, 2004)

*Re: FV-BumpIt(1241932954937) (ABA Scirocco)*

Yeah I still have that part, I had to bypass it to get it to run correctly but I may have had it plumbed up wrong. I'm going to double check it and see if it works. That diagram is awesome, thank you! http://****************.com/smile/emthup.gif


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## Southcross (Jul 2, 2004)

*FV-QR*


_Quote, originally posted by *ABA Scirocco* »_










that might be the solution I was looking for, for my drag car.... what are the sizes of the fittings?


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## ABA Scirocco (May 30, 2001)

*Re: FV-QR (Southcross)*

The three fittings that point to the left on that picture are 8mm (5/16"), the other one is 10mm, 3/8" hose fits very nicely, I know this because I replaced that hose on my car on Monday.


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## Southcross (Jul 2, 2004)

*FV-QR*

hmmmm... that might be too small for my needs then... hmmmmm


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## Vodoo48 (Jan 8, 2004)

*FV-QR*

I still cant get it to run right with that plastic box hooked up. It runs fine without it but it just starves for fuel when I rev it up. I'm going crazy! I really want to run the double header this weekend, sunday and monday, I need to figure this out!


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## ABA Scirocco (May 30, 2001)

*Re: FV-QR (Vodoo48)*

How's the pick up in the fuel cell? A friend of mine had fuel starvation issues in his race car, the problem turned to be the foam inside the fuel cell was old and starting to break down and little bits were breaking off plugging up filter lines etc. Anyways, good luck!


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## Vodoo48 (Jan 8, 2004)

*Re: FV-QR (ABA Scirocco)*

Thanks man, but the fuel cell and foam is brand new. I'm going to play with it tomorrow to see what I can get done


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## Vodoo48 (Jan 8, 2004)

*FV-QR*

Ok, stupid me. I had the stock, high-pressure pump wired backwards so the pumps were fighting each other and backfeeding into the engine return line. I feel like a horse's @$$. Anwyay the car runs great now! Thanks for the help everyone!


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