Will this work? EFI return line idea

Discussion in 'High Tech Retrofits' started by Penix, Jun 17, 2007.

  1. Penix

    Penix Veteran Member

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    So I ran into a guy today who has a late 60's Nova with a TPI, and here's what he did for his return line.

    He's running a Holley 12-920 in the proper location, but rather than plumbing a return line into the tank at all, he just placed an AN T-fitting between the fuel pump and the tank and ran the return line to that.

    Now, the logic makes sense to me, and it works fine for him (even at the strip) but what do you guys think? If this works I think I'd rather do this than plumb the tank itself, until I can buy the right model/year specific baffled EFI tank for my ride.

    Looking forward to your input!

    Thanks

    Joel
     
  2. Rick WI

    Rick WI Veteran Member

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    I am not clear on what you are saying the guy actually did but many new car systems are setup as a sort of returnless system. Rather than setting up the return after the fuel rails it is plumbed so that the the return is back at the pump in the tank. If I remember correctly Mopars are set up this way.
     
  3. Knuckle Dragger

    Knuckle Dragger Mayor of Simpleton Staff Member Lifetime Gold Member

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    It sounds like it should work. One possible issue I can think if is the fuel is going to be continually heated. When the fuel goes from the return to the tank if mixes with fuel that has not been heated up on it's journey to the engine, and then keeps the fuel temp down. How much heat we're talking have not idea. It may be one of those over thinking things. Are you going with baffles in the tank, or a reservoir? The return could also go tot the reservoir.

    The system Rick is talking about is becoming popular. The fuel dead heads into the rail and the ECM will duty cycle the fuel pump to maintain proper pressure. Ford calls their a "return-less fuel system" OF course that's not going to work for your set up.
     
  4. Penix

    Penix Veteran Member

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    Here goes a pic to better illustrate what I'm talk'n about. Not a bad job for a few minutes in "Paint" eh? LOL

    [​IMG]
     
  5. Penix

    Penix Veteran Member

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    Okay, so how about some fuel coolers, one for the pre-line and one for the post-line?

    How necessary do you think a baffled tank would be innitially? I don't plan on race'n this thing right off the bat, I just want something that will work until I can afford the year specific baffled EFI tank.
     
  6. Knuckle Dragger

    Knuckle Dragger Mayor of Simpleton Staff Member Lifetime Gold Member

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    You must have something. On a carburetor car the fuel bowl is the reserve. If you turn hard and the fuel pick up sucks air for just a bit it's no big deal. On a fuel injection car, if it sucks air you will have air in the line. So you either need to build or adapt a baffle tank, or make an in-line reservoir, and use two pumps. One the feed thee reservoir (low pressure, just move fuel from big tank to little tank) From the the reservoir a high pressure pump to the fuel rail.

    Now I have heard of guys that don't run either, but keep the tank half full or at some level they feel comfortable with, and they say they never have issues. I personally was not willing to take the chance of stalling in the middle of a crash avoidance situation. But I'm paranoid like that too.
     
  7. Doug Jaynes

    Doug Jaynes Veteran Member

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    you can get by without the baffled tank for a while, for daily driving it isnt much of an issue but would be with a road race car. Its not that hard to convert a stock tank by putting a sump in it and sitting the in tank pump right at the base of the sump. Cut an access panel in the top for service.

    Doug
     
  8. msb80sc

    msb80sc Veteran Member Lifetime Gold Member

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    Yes Mopars have not been using a return line for awhile. Bad thing with it is that anything in the fuel rail that does not go through the injectors, stays in the rail. Water, gunk, trash. Have seen rails that look like the Belvedere Car and needed replacing.

    BTW, I am running a setup like that on my car. Filter, pump and 3 port regulator all back buy the tank. Stock tank isn't setup for a return and I didn't want to deadhead the pump, so that's what worked.
     
  9. flyboy367

    flyboy367 Veteran Member

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    wow that makes some good sense. i was even thinking of when i change my sending unit i would use a bar to make a bump like an inch or 2 in the bottom rear of the tank then drill it and install a fitting and use that to run to my fuel pump when i go efi. since my tank is new, and i dont feel like going thru all the steps to dry it out so i can weld a sump. this way fuel will always get to the line and when i hit e on my gauges ill still have enough so i wont burn out the pump.
     
  10. flyboy367

    flyboy367 Veteran Member

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    whoa just found this on a site and cant think how easy it would be to make and we could keep our tanks the way they are.

    http://www.tanksinc.com/index.cfm/p...category_id=61/home_id=61/mode=prod/prd84.htm

    using an a in tank pump mounted to the bottom of that sump pan we could probably use our stock sending unit and just add a right angle fitting to the top of the tank or unit for a return line. im gonna have to look into this more
     

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