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Help me design my 20B fuel system

Old 08-30-08, 11:40 AM
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Help me design my 20B fuel system

Just got back from testing at Buttonwillow and had serious fuel starve issues...my current setup is:

- 15 gal ATL fuel cell
- 3-door surge tank inside cell, with -10 pickup
- -10 pickup from surge tank connects to top plate of fuel cell via -10 hose
- Aeromotive A1000 fuel pump sits on top of fuel cell and is fed via -10 from top plate
- A1000 outlet is -8 to primary fuel rail which is -8 to secondary rail then -8 back to FPR
- FPR is -8 return to the top plate of the fuel cell which dumps back into cell

Evidently this isn't working, as I get massive starvation coming out of sharp corners. I have seen and heard of other setups using a large (1 gallon type) external surge tank which has a return coming into it, but not exactly sure how these work. Any help appreciated!

EDIT: Is this a decent solution? http://www.sdsefi.com/techsurge.htm - I assume I could have two feeds coming from the cell into the surge tank via 2 Walbro's for example and then use my existing A1000 to pump from the surge tank to the rail...

Last edited by thetech; 08-30-08 at 11:51 AM.
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Old 08-30-08, 12:43 PM
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Couple comments....

Are you sure the surge tank is sitting flush with the bottom of the cell? I had problems with mine and had to be very careful when installing it.

You may consider feeding the return line from the plate to the actual surge tank, that way you are constantly dumping fuel into the surge tank as well as it's getting it from the trap doors.

Not sure about the A1000 pump, but I have heard with the Bosch 044 that I use that it was not a good idea to mount on top of the cell. That's what I had wanted to do for ease of installation but was suggested that it needed to be mounted below the cell, which meant under the vehicle on the angled downslope area. Unless the A1000 pump is a "puller" pump, it needs to be mounted lower.

I've had no problems since going to this...

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Old 08-30-08, 12:49 PM
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Thanks for responding Mark. how did you ensure that the tank was sitting flush with the bottom? I basically notched the foam so that the surge tank is kind of 'wedged' in there, it is the identical tank to the one you have pictured above.

Good idea on the return, I had been told that the A1000 could work fine above the cell but it doesn't appear to be
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Old 08-30-08, 01:08 PM
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I didn't notch the foam at all, not sure how your foam is but as you can see mine is just blocks. I took out almost all the foam, then set the tank on the bottom and wedged it in good with the foam. You have to be careful because I noticed as I would try and put the plate back the stiffness of the braided hose would cause the tank to shift. I had to get it just right for the tank to sit on the bottom. Of course, there isn't really any need for fancy AN fittings and braided hose but what the heck.
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Old 09-02-08, 06:26 PM
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Ok so the more I think about this and the more I talk to people (thanks BigAl) the more confused I am about what the problem really is. In reality, it most probably is NOT the return, as this is happening under completely full loads of fuel (like full to the brim point of overflowing loads of fuel). The return should really not matter at that point as the surge tank is still completely submerged in fuel.

After talking to Aeromotive today they seemed to suggest that it didn't really matter very much if the pump was mounted above or below either, so I am left somewhat confused. I'm moving ALOT of fuel and not sure if somehow that is the issue. Could it be the vent?

You can see the effect it has towards the end of this video:

http://gallery.me.com/amir.haleem#100029
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Old 09-04-08, 12:11 PM
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Is your in-tank surge tank positioned at the rear of the cell so you can ensure fuel under acceleration? Does your pickup point in the surge tank pick up from the middle of the rear of the surge tank? Is it possibly getting blocked in any way? The only other thing I can think of is a possible line restriction under acceleration, possibly a line getting stretched or kinked as the engine torques a little.

my $0.02
-Trent
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Old 09-04-08, 06:10 PM
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Try 2 -6 fuel pick ups. one at each rear corner of the cell. then run both feeds through 2 Bosch fuel pumps then into a Y and into a -6 line all the way to your engine. This is what we run on the car we are racing now and it works great. Now i understand you have a 3 rotor in comparisson to our 2 rotor but we used that same set up in my turbo street car that did 516 RWHP so volume and pressure should not be a problem.

Good Luck!
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