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Thread: Recommended Fuel Pressure?

  1. #1
    Fuel Injected!
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    Recommended Fuel Pressure?

    New engine for my Suburban, trying to tie up some details.

    Fresh L31 Vortec longblock, internally stock. Fresh 5.7 injectors. Ultimate'd throttle body. Mercruiser TBI intake, Thorley tri y's w/ Y pipe.

    Looking for reccomendations on fuel pump and FPR spring. Not certain on what pressure I should be looking for. 14? 16? 18?

  2. #2
    Fuel Injected!
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    When you say 5.7 injectors, I assume you mean 60 lb/hr injectors? An 18 psi spring will be a small bump in fuel pressure, without supplying too much fuel.

    What year is the Suburban? An EP381 pump will supply more than enough fuel to provide 18 psi and is a direct replacement in the TBI trucks and it came stock in Vortec trucks also.
    1990 Chevrolet K2500, RCLB, Blueprint 383 TBI (16197427 ECM / 61 lb/hr / 16 psi FP), NV4500, NP241C, 4.10

  3. #3
    Fuel Injected!
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    I'm assuming they are the 60#/hr injectors. I haven't pulled them yet to verify.

    Sub is an 88 K20.

    I appreciate the info.

    <a href="http://s151.photobucket.com/user/JasonCampbell1180/media/My%20Trucks/24X625011.jpg.html" target="_blank"><img src="http://i151.photobucket.com/albums/s160/JasonCampbell1180/My%20Trucks/24X625011.jpg" border="0" alt=" photo 24X625011.jpg"></a>
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  4. #4
    Fuel Injected!
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    Quote Originally Posted by JCampbell View Post
    New engine for my Suburban, trying to tie up some details.

    Fresh L31 Vortec longblock, internally stock. Fresh 5.7 injectors. Ultimate'd throttle body. Mercruiser TBI intake, Thorley tri y's w/ Y pipe.

    Looking for reccomendations on fuel pump and FPR spring. Not certain on what pressure I should be looking for. 14? 16? 18?

    I would use the 1992-1994 4.3 W CPI Astro pump. Along with an external regulator. Would try around 20 psi with the stock 61 lb/hr 350 injectors.

    Kinda doubt you will like the stock L31 cam in that setup.
    Last edited by Fast355; 02-19-2017 at 09:12 AM.

  5. #5
    Fuel Injected!
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    Quote Originally Posted by Fast355 View Post
    I would use the 1992-1994 4.3 W CPI Astro pump. Along with an external regulator. Would try around 20 psi with the stock 61 lb/hr 350 injectors.

    Kinda doubt you will like the stock L31 cam in that setup.
    What did the 5.7 Vortec/TBI marine engines run for injectors and at what fuel pressure?
    I agree with your fuel pump recommendation, its the EP381 which was also used on the 1996-97 Vortec 4.3/5.0/5.7/7.4 and the GMC turbocharged 4.3 trucks 1991 Syclone and 1993 Typhoon.
    That's the same pump that Chev Performance Parts recommends for their Ramjet 350(351hp@5000rpm/403lb/ft@3600rpm and Ramjet 502(502hp@5300rpm568lb/ft@3600rpm/Ramjet 454-ZL1(510hp@5750rpm/493lb/ft@4250rpm) crate engines.
    Certainly enough fuel for a TBI Vorec engine.

    peace
    Hog
    Last edited by Hog; 02-24-2017 at 06:00 PM.

  6. #6
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    Quote Originally Posted by Hog View Post
    What did the 5.7 Vortec/TBI marine engines run for injectors and at what fuel pressure?
    I agree with your fuel pump recommendation, its the EP381 which was also used on the 1996-97 Vortec 4.3/5.0/5.7/7.4 and the GMC turbocharged 4.3 trucks 1991 Syclone and 1993 Typhoon.
    That's the same pump that Chev Performance Parts recommends for their Ramjet 350(351hp@5000rpm/403lb/ft@3600rpm and Ramjet 502(502hp@5300rpm568lb/ft@3600rpm/Ramjet 454-ZL1(510hp@5750rpm/493lb/ft@4250rpm) crate engines.
    Certainly enough fuel for a TBI Vorec engine.

    peace
    Hog
    46 lb/hr injectors with a 30 psi regulator.

  7. #7
    Fuel Injected!
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    Quote Originally Posted by Fast355 View Post
    46 lb/hr injectors with a 30 psi regulator.
    Thanks Fast, much appreciated.

    peace
    Hog

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