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Thread: Sumping a stock fuel tank

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  1. #1
    Join Date
    Nov 2003
    Location
    Denton Texas
    Posts
    20,689

    Sumping a stock fuel tank

    Sumping a stock fuel tank


    Have you ever had a fuel starvation problem during hard launches? The OBS trucks are notorious for this issue. Here is the solution, a rear mounted fuel tank sump. Below is a list of all parts used. SummitRacing.com was sourced for all parts.

    I use 1" x 1/8" flat bar to make the mount for the pump and filter. To isolate pump noise I wrapped the clamped pump and filter with an old 10-speed tire tube.

    This list includes all items for a return style fuel rail.

    1/2 NPT dual outlet sump CEE-4041

    Hose purchased for RCSB
    -6AN = 3/8" inside diameter (20 feet) SUM-230620
    -8AN = 1/2" inside diameter (6 feet) SUM-230806
    1/2" INSULATED CLAMP 10PACK SUM-G1882

    outlet side:
    1/2 NPT male to -8AN male outlet fitting SUM-220847
    -8AN female x 90 degree hose fitting SUM-220887
    -8AN hose
    -8AN female to -8AN hose straight fitting SUM-220890
    -8AN male to 18mm x 1.5mm male fitting AER-FBM2244
    Bosch 044 pump held to the frame by 2.5" Tbolt hose clamp (2) SME-240250 (clamp)
    Weber carb 12mm x 1.5mm male x -6AN male adapater EAR-991944ERL
    -6AN female to -8AN female straight swivel EAR-915186ERL
    -8AN Summit fuel filter held to the frame by 1.5" Tbolt hose clamp SME-240175
    -8AN female to -6AN male reducer EAR-9892086ERL
    -6AN female to -6AN hose fitting SUM-220690
    -6AN hose
    -6AN female to -6AN hose fitting SUM-220690
    -6AN female to -6AN male gauge adapter swivel fitting (optional) R-100199ERL
    -6AN male to 3/8 ID Russell fuel line adapter 640850

    return side:
    1/2 NPT male to -6AN male outlet fitting EAR-981668ERL
    -6AN female x 90 degree hose fitting SUM-220687
    -6AN hose
    -6AN female to -6AN hose fitting SUM-220690
    -6AN male to 5/16 ID Russell fuel line adapter 640860

    The sump will need to be welded to the rear floor of the fuel tank. This will require removal of the fuel tank and plastic liner on the OBS trucks. Do not attempt to weld this in yourself, take the empty fuel tank and sump to a radiator shop that can cut and weld it with a shielding gas filling the tank to prevent the risk of explosion from the gasoline vapors.

    Remove the factory fuel pump from the OBS pump assembly and close off the fuel pump supply and return tubing by welding or flatten it and bend it over on itself. You can also remove the supply and return fittings on the top of the fuel pump assembly. Take some JB Weld and fill in the holes. Cut and remove the wires that went to the old pump. All that should be left is the vapor vent tube going to the filler neck and possibly the fuel vapor line if you decided to keep it, I close it off.

    When you assemble the tank you will need to cut an area from the plastic liner to clear the sump. The parts above are listed in order of assembly going from the fuel tank towards the fuel rail. If you're worried about keeping the aluminum fittings pretty, be sure you buy AN fitting wrenches.





    Last edited by farmtruc; 06-19-2014 at 02:51 PM.
    See my truck data in the "My Garage" section here... http://www.ls1truck.com/forums/my-ga...tml#post191709

  2. #2
    Join Date
    Dec 2005
    Location
    Chicago-ish
    Posts
    183
    Nice. At one time I was thinking of making a metal tank so I could do the same. Your long list of fittings looks expensive. This is another thread that needs to be included in the price list when a newbie asks "How much will (xxx) HP cost?".
    2000 Sierra 2500 HD. 408 (11-2007) Whipplecharged, Big (18x24x4) FMIC.

  3. #3
    Join Date
    Dec 2003
    Location
    Newark, Tx.
    Posts
    1,312
    This tank was also coated inside. It will prevent the sump from rusting and ensure a long life. Select radiator shops can coat the inside of the tank after its sumped.
    '92 GMC reg. cab, step side. 7.32@ 92.3. SOLD
    http://videos.streetfire.net/video/d...d700c6401f.htm
    New project: '00 S-10 ext. cab, ZQ8, 370, T-56, daily driver.

  4. #4
    Join Date
    Oct 2008
    Location
    Houston
    Posts
    819
    Tip: Aeroquips "socketless" hose is NHRA rated, cheaper and easier to
    work with than braided stainless. Hose ends are just push a barb'd fitting and put small
    hose clamp on for little extra security. ( but not too tight)

    If you've ever wrestled with getting hose ends on stainless hose you'll love
    this stuff.

    Comes in blue and black.
    2002 Tahoe 4.8 - soon to be turbo'd - SOLD
    1989 Mustang - LX Vert - 351W-TT - 2inches of dust covering it
    2012 Raptor - 497rwhp at 10psi
    If you aint breaking - you aint going fast enough

  5. #5
    Join Date
    Nov 2003
    Location
    Denton Texas
    Posts
    20,689
    Yeah, that stuff is nice but the price was about the same when I did this one. You still have to buy the same number of connectors and the hose wasn't any cheaper. Its a lot more flexible for sure. This was my first braided line setup and I had no problems assembling everything in my home garage. My only complaint is the stainless likes to stab you when you're assembling the ends. I used an abrasive cutoff wheel to cut the hose to length.
    See my truck data in the "My Garage" section here... http://www.ls1truck.com/forums/my-ga...tml#post191709

  6. #6
    Join Date
    Feb 2009
    Location
    NC
    Posts
    104
    Looks good, nice install.
    Pretty creative using 10 speed tire tube.

  7. #7
    Why didn't you run -8AN all the way to the fuel rail?

    I'm wanting to do the same thing but with a fuel cell and the socketless hose mentioned above.

    I'm thinking of using a Walbro 255 but I think the hose barb fittings included are 5/16. Would this pump be a bottle neck or should I just replace the 5/16 fittings with 3/8 fittings?

    I'll post pics of my setup when I get it finished.

    thanks, Kris
    Last edited by knute_gis; 04-29-2009 at 04:36 PM.
    1997 GMC RCSB
    LS6/T56

  8. #8
    Join Date
    Oct 2003
    Posts
    470
    Quote Originally Posted by knute_gis View Post
    Why didn't you run -8AN all the way to the fuel rail?

    I'm wanting to do the same thing but with a fuel cell and the socketless hose mentioned above.

    I'm thinking of using a Walbro 255 but I think the hose barb fittings included are 5/16. Would this pump be a bottle neck or should I just replace the 5/16 fittings with 3/8 fittings?

    I'll post pics of my setup when I get it finished.

    thanks, Kris
    -6(3/8") fuel supply line is more than sufficient for over 600 h.p.

  9. #9
    Join Date
    Jan 2008
    Posts
    14
    good write up... Im doing something similar, just a little more extreme...

    here is my custom surge tank... my main tank will fill this one. This will house an aeromotive eliminator and an aermotive fuel filter. -8 and -10 lines in and out of this.


  10. #10
    Join Date
    Nov 2003
    Location
    Denton Texas
    Posts
    20,689
    Keep us updated on the install.
    See my truck data in the "My Garage" section here... http://www.ls1truck.com/forums/my-ga...tml#post191709

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