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Thread: Boost VS RPM?

  1. #1

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    Boost VS RPM?

    Good day Greenhulkers. I just went from a stock X charger to the ET 137 +4mm. Got a 15/22R -3 mm and with the x charger it pulled 8050 RPM ~ 10 PSI, With the ET 137 it still just pulls 8050 ~ 12,5 PSI. AFR at WOT is 11.7. Any ideas ? Still to tall prop?

    Mods:

    Riva Racing ECU w/50's
    Riva valvetrain
    Riva RRFPR
    Riva
    thru hull exhaust
    ET 137 +4mm
    XS IC
    4" Kanalflex



  2. #2
    My bet is you went butt rich and killed the power. You need a way to data log it and tune it. Those 50s are too small and most likely are locked wide open at those pressures.

    Andy

  3. #3

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    To small? Aren't people running the ET 137 with 48s and RRFPR on stock ECU? Perhaps reduce fuel pressure a bit?

  4. #4
    My mechanically rock stock RXPX runs 100% DC as loged on my CMD. The ski is running a VTech setup under the CMD. My stock injectors are maxed out and really about 15% too small. The RRFPR will only max the injectors out at too fat. The cure is a tuner and a way to tune it.

    Andy

  5. #5
    Boost addict hotbird's Avatar
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    Thar et wheel is pretty powerful. Check your intercooling piping. Few of us blew the pipes appart at the couplings right after installing the wheel.


    But your psi looks to be ok.

  6. #6
    Boost addict hotbird's Avatar
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    Edit sorry must not have read all the details.

  7. #7
    mikelytle1077's Avatar
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    if they are the delphi style injectors be careful they lock up at higher pressures and that will toast your motor

  8. #8
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    something is not right in my opinion since your running a riva ecu. my x charger was on the limiter with vtech rev limiter at 8300 in cool weather with a 15/20 prop. it will pull 8250 with the 82 mm ring in 80 degree temps, humidity, water, and engine. with the riva ecu you shouldnt be down 600 rpms. i run bosch which im told flow more than the delphi 50's. im at 12 ish wot. something is not right with the setup you have. you dont need a cmd. fix the problem before throwing cash at it and chasing your ass.

  9. #9
    skigolfnut's Avatar
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    Do you have an AFR gauge? if not you need to get one,
    If you do not know what your AFR's are you are just guessing,
    Why would anybody run with mods and not have one, I just don't get it,

  10. #10
    imp0ster's Avatar
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    The extra 2.5psi would easily give you more RPMs. You're probably seeing knock. Does it pull hard as hell to 8050 and stop dead or does it get to about ~7900 and creep up?

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