Boost problems

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  • #1

    Boost problems

    I have installed a few upgrades to wind the boost up

    Following mods - Walbro fuel pump
    Malpassi fpr
    near new stock injectors
    Profec spec b boost controller
    new leads and plugs
    new water pump and timing belt

    I have turned the fuel pressure up to 42psi and i think stock was 36. I turned the boost up on the controller also and when i took it for a drive i noticed the once it went over 11psi it would start lagging and not boosting properley. i have read up about whinding boost up and i was sure i done everything correct.

    anyone know if i am missing something?
  • #2
    Not boosting properly? Gap too high? Although, at 11psi, I doubt it.
    BLOZ UP.com
    It is not recommended to confirm proper installation by driving into walls or other barriers as this could cause personal injury or damage to the vehicle.
  • #3
    shouldnt the gap on plugs be right since the are new? it feels real good up until it goes over 10 psi and it starts running sluggish and lagging heaps.

    Would my lifters ticking hard be the reason why this could be happening?
  • #4
    considering you listed everything else… do you still have a pop off valve installed? That would open up, dump the air, cause excessive rich condition…
  • #5
    It wouldn't go over 8psi if that were the case. I wouldn't run over 10psi without an intercooler personally. I've seen bad things happen.
    What plugs did you install? Stock NGK should be used
  • #6
    barkrz18 wrote: shouldnt the gap on plugs be right since the are new? it feels real good up until it goes over 10 psi and it starts running sluggish and lagging heaps.

    Would my lifters ticking hard be the reason why this could be happening?
    They are usually pre-gapped, but I always check before I pop them in.

    I was wondering if you were blowing sparks out. I doubt it, but it's possible. So, either that, or it's running too lean or rich. I would find out before you try it again.
    BLOZ UP.com
    It is not recommended to confirm proper installation by driving into walls or other barriers as this could cause personal injury or damage to the vehicle.
  • #7
    shouldnt the gap on plugs be right since the are new? it feels real good up until it goes over 10 psi and it starts running sluggish and lagging heaps.

    Would my lifters ticking hard be the reason why this could be happening?
    Lifters ticking hard??? Sounds like detonation! You upgraded the fuel pump but not the injectors?
    Whats the timing set at!

    I can't run past 9psi on my stock 87t before it starts running lean, and starts to denonate!

    Just a thought.
    88na2T-s13,q45 swap 12.6@110mph
    87T 2+2 auto,stock
  • #8
    Get an intercooler.

    In fact, take a video of it so we can see what happens 1st hand.
  • #9
    I am having a hard time believing his motor is detonating at 11psi. There has to be an underlying cause if it is, because no VG ive ever had cared about 10ish psi. I'd still STRONGLY suggest looking at your fuel, and any vacuum leaks as that would definitely not help you.
  • #10
    Mine did this as well for a short bit and it tunred out to be the factory POP off valve bleeding off. Lower you spark gap and get a wideband. Won't have to worry about guessing what's up as much.
    "Its the s12's sexy over weight step daughter, the z31"
  • #11
    You turned up the base fuel pressure by 6 psi. I'd guess considering the very conservative tuning of the stock ecu that you're running too rich at that point. You might consider returning the fuel pressure and boost to stock levels and evaluate performance then. If the car runs perfect you know it is related to one of the two and that there are not other problems with the car. Then you diagnose accordingly.
    http://z31performance.com/forum/viewtopic.php?f=5&t=147
  • #12
    oh sorry i forgot to mention intercooler with hks bov.

    The stock releif valve has been blocked off.

    i also have a fuel pressure gauge.

    and when it goes over 11psi it starts lagging in speed
  • #13
    have to say, i reduced my fuel pressure because it was wayyyyyyyyyyyyyyy higher than factory, and then i blocked off the intake filter with some cardboard to test it's temperature sensitivity.

    runs much cooler and much better than it ever did.
  • #14
    Have you setup you BOV properly? 11psi+ could be to much for you bov if it isnt adjusted correctly. Try increasing the spring tension.
  • #15
    The spring tension only affects operation under vacuum. The spring has to be stronger than the engine's vacuum. Boost pressure and the spring keep it closed otherwise.
    BLOZ UP.com
    It is not recommended to confirm proper installation by driving into walls or other barriers as this could cause personal injury or damage to the vehicle.
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