'72 gas tank modifications for EFI

Discussion in 'High Tech Retrofits' started by hutchenc, Oct 9, 2011.

  1. BondoSpecial

    BondoSpecial Veteran Member Lifetime Gold Member

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    I ran 2 inline pumps, one low pressure one high pressure, and an external surge tank. I have run my car (accidentally) down to 1 or 2 gallons in the tank and was still doing full on WOT runs with it and did not notice....you are going to NEED some sort of baffling or inline surge capacity if you are going to keep the stock tank. My setup is a lot of plumbing an ugly but I'd wager a lot more effective than those little slosh trays in tank. I added a 3/8 return to my stock sender....see my 79 project thread for details and plumbing. Might not be for everyone but it is an extremely conservative way to prevent starvation, you could run my car upside down for a while and it would still be fine (I used a one gallon surge tank LOL)
     
  2. anesthes

    anesthes Veteran Member Lifetime Gold Member

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    I'm running the LSx (99-02) fuel pump module with the vetteworks weld on ring.

    It has three ports. Pressure, regulated return, and free-flow return. You can use the built in regulator with is 58psi, or you can use the free-flow return and a rail mounted regulator. I'm using GM fuel connect to -6AN adapters from russel, and braided -6AN fuel hose.

    I like the idea of being able to adjust fuel pressure at the rail, but both ways work. Either way, the LSx bucket/module is the way to go. You can go around corners without running the pump dry, it's quiet, you only have 1 pump to deal with and plumbing is plain and simple.

    -- Joe
     
  3. Fbird

    Fbird Veteran Member Lifetime Gold Member

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    Made my own "tank works" kinda thing.....pump on a stick (lol). mine deosn't use sheet metal screws.....more like aluminum rings with o-rings in them :)
    Didn't realize other folks did that stuff....BACK when I was doing mine....now just have to redo it to add BAFFLES....:( PITA

    I still haven't got it out of the garage ...yet!!

    last thing....WALBRO sux!!! get the aeromotive 340.....same size but...340lph...and its aeromotive.
     
  4. anesthes

    anesthes Veteran Member Lifetime Gold Member

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    Nothing wrong with walbro. One of the best pumps in the market, with millions on the road today. Almost all walbro failures are due to contamination of fuel (dirt, metal shavings, etc) due to lack of proper filtering.

    -- Joe
     
  5. Fbird

    Fbird Veteran Member Lifetime Gold Member

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    I beg to differ in MY situation....fuel tank wwas completely scrubbed....by me...wiped with terry-cloth...problem persists......sometimes...it looses its prime..WTF?....it is submerged in 12 gallons of fuel...how the hell can it loose its prime?......everytime i turn the key it's a 50 50 shot if its gonna work.(POS)...just waiting to swap out the aeromotive when I get done making the baffles...PITA
     
  6. BondoSpecial

    BondoSpecial Veteran Member Lifetime Gold Member

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    I have run multiple Walbro 255 pumps (inline) and they are the quietest pumps I have ever used. I have never had a problem with them.
     
  7. anesthes

    anesthes Veteran Member Lifetime Gold Member

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    Don't know what the issue is with yours, but like I said with millions of pumps sold and on the road, I wouldn't go around bashing a company based on a single experience.

    Have you replaced it with an aeromotive ?

    -- Joe
     
  8. Fbird

    Fbird Veteran Member Lifetime Gold Member

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    still waiting to line up a buddy's welder :( havent had time to put into the bird as of late....

    And NO I didn't BASH walbro over 1 single experience.......I did my research to find this pump for use INSIDE my tank....cause the junk mounted outside is too dam LOUD. The Walbro 255 was the most recommended and most popular...so....got 1 of those....lasted approx 8 hrs run time....then 0 psi.
    mind you this is WHILE i am making/installing a Holley MPI system....upon full disassembly of fuel system....zero answers as it is cleaner than my whiskey glass!!...order another.......yeah....worked for almost 30 hrs run time...then 0 psi........the dam thing is 4" UNDER gasoline......how the hell does that loose its PRIME.....i used my vacuum pump to "pull" some fuel thru it.....it works...sometimes.....sometimes.....NOT (POS) $300 2 pumps 1/2gallon Jack Daniels.......not to mention all the fun of dropping a fuel tank with 16 gallons in it!!!!
     
  9. chris the rat

    chris the rat New Member

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    I think the vetteworks solution together with the 4gen pump assemly looks like a really nice and easy way to go to get an EFI functioning tank. I just don't understand vetteworks claim that the unit can handle 600hp.Racetronix have a upgrade pump that is supposed to support 600hp. I sent an email to them and asked about this and they answer really fast that the stock 4gen unit pumps 30g/s which equals to 238pounds/hour, they sent this link http://delphi.mycarparts.net/products/Delphi-FG0154?product_application_id=270426773 This would mean about 400hp is max. The racetronix flows 357pounds/hr which would be OK up to 600hp. I tried emailing vetteworks but the email bounced and I could not find a better address at there site. As I see it vetteworks are a bit optimistic about the power supported, or the unit they sell is upgraded with a better pump or the link from racetronix does not show the correct pump unit. Here are some links to vetteworks solution:
    http://www.vetteworksonline.com/catalog/product_info.php?cPath=94&products_id=197
    http://www.vetteworksonline.com/ls1_conversion_fuel.htm
    http://www.vetteworksonline.com/catalog/product_info.php?cPath=94&products_id=178
     
  10. anesthes

    anesthes Veteran Member Lifetime Gold Member

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    Ok. So lets see.

    That unit operates at 400kpa, and flows 238lbs/hr at 400kpa (58psi).

    Now we have racetronix F99, which is a walbro 255lph (g340) with a top screw removed and a nipple screwed in for the venturi. At 58 psi, this pump produces 49 gallons per hour which is 294lbs/hr.

    Then we have horsepower. At a BSFC of .5, I need 1/2 lb fuel for each HP. So 238 * 2 = 476hp. The Walbro 294 * 2 = 588hp.

    At .45 BSFC the stock pump jumps to 528 hp and the walbro 653. On a turbocharged motor at .60 BSFC 396hp and 490.

    Now what happens if we change the fuel pressure? Good question.

    I don't have a chart on the delphi, but the walbro like I said produces 49gph at 58 PSI. At 43.5 PSI it produces 58gph, which is 348lbs/hr.

    So there is a lot of variables involved, operating pressure, what engine it's on, etc.

    -- Joe
     

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