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tbi tinkerer

Discussion in 'The Garage' started by only 31s, Mar 4, 2005.

  1. only 31s

    only 31s 1/2 ton status

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    has any one tried turning up the fuel pressure through the tbi{not sending more flow to it but adjusting the pressure inside it] if so what results did you have? aside from diag codes? any quicker acc or more torq?:grin:
     
  2. dirtwarrior17

    dirtwarrior17 Banned

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    depends on your motor and mods... an adjustable regulator on a stock 350 should get you 10 or so hp at the flywheel.
     
  3. fortcollinsram

    fortcollinsram 1/2 ton status

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    I have a built TBI 454. I am using the GM vacuum referenced fuel pressure regulator. It holds 12psi of pressure at idle and jumps it to 18psi at WOT. The only problem I have is the ACDelco replacement fuel pump can't keep up with the engines fuel demand at WOT above 3000rpm.


    I have used a JET FPR too but it basically sucked. Too rich or too lean...never just right...but it was still better then the stock FPR, which was ALWAYS too lean with the 454..

    Chris
     
  4. Thunder

    Thunder 3/4 ton status

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    Turning up the stock fuel pressure is pretty much mandatory on TBI if you do any afternmarket stuff like Headers, Exhaust, Intake mods. Stock pressure is pretty low and to get the most out of anything that adds more air flow. You need to turn up the fuel pressure. Changing the FP will not cause the ECM to throw any codes, at least from my experience.
    I run my mild built TBI 350 at 14 psi. I get the best mix of performance and fuel milage at that PSI. But all engines are diferent.

    The vacume controled FPR that Chris is talking about is also a very good unit.

    Here's some good reading about modding the stock FPR
    http://www.thirdgen.org/newdesign/tech/tbi-afpr.shtml There is some more good TBI stuff in their Tech articles also.

    http://www.cfm-tech.com/GM_tbi_tuning_tips.htm More good info and they sell TBI performance upgrades too.
     

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