GC8 STi Fuel Injector question

Discussion in 'Modifications & DIY how-to' started by revel, Mar 4, 2007.

  1. revel

    revel Member

    so its time for me to upgrade the stock 555cc injectors from my V6 STi. i plan on going with a set of 800-1000cc Sard injectors. what i need to find out is-

    am i top feed or side feed?
    do i want low impedance or high impedance (what the heck is the difference)?
    is a fuel rail a good idea at this point?
    if so who makes one for the V6 STi?
    will a USDM WRX fuel rail bolt-on and function properly without any modifications?
    or will it need to be modified?

    i have done some research but keep finding both top feed and side feed as being 'stock bolt on injectors'. as for the impedance thing i dont understand the differences enough to make the call. as of now my injectors are hitting around 89% at 7k rpms so i cant get near the 8krpm redline. my plans for the GC are mostly autocross for now with as many trackdays as i can afford.

    thanks in advance for any info and/or advice.
     
  2. revel

    revel Member

    not sure if any of this would make a difference, but mods:

    V6 STi RA EJ207
    IHI VF28
    Fujitsubo headers w/ catless up-pipe
    Helix catless dp
    HKS HiPower exhaust
    HKS SSQV
    ARC SMC-R radiator
    Apexi PowerFC
    V6 STi RA 4.444 DCCD tranny
    MonsterSport lightwieght flywheel

    thats all for power/drivetrain.
     
  3. nsvwrx

    nsvwrx Active Member

    side feed!
     
  4. Doug@DBW Motorsports

    Doug@DBW Motorsports Active Member

    You need a topfeed high impedance injector. You could run a low impedance injector as they are cheaper and go higher than 650cc, but you will need to run an injector resistor box for the low impedance.
     
  5. revel

    revel Member

    so the top feed will drop in? you think 850cc will do the job or should just go ahead and get the 1000cc? what about a fuel rail?
     
  6. nsvwrx

    nsvwrx Active Member

    i thought STI injectors were sidefeed?
     
  7. calmnothing

    calmnothing Shlimp Flied Lice Supporting Member

    I'm pretty sure v6 injectors are sidefeed. Onlythe usdm injectors are topfeed
     
  8. miloman

    miloman Retired Admin

    USDM STi injectors are sidefeed
     
  9. Doug@DBW Motorsports

    Doug@DBW Motorsports Active Member

    Negative, the version 6 runs topfeed injectors. Subaru didn't switch to side feed untill 2004 version 8 motors.
     
  10. revel

    revel Member

    fuel rail?
     
  11. nsvwrx

    nsvwrx Active Member

    thanks doug!
     
  12. revel

    revel Member

    after i finally got a chance to push things around and get my head into the engine bay the ver6 sti ra is side feed.

    so is one better than the other for different applications or does not really matter?


    again-does anyone know what fuel rails fit the Ver6 STi GC?
     

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