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  1. #1
    camar0's Avatar
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    Question New speeds but speed lacking..... thoughts?

    RXP speeds were 74mph at 8440 rpm, seems slower than expected

    mods:
    15/20 with -2 pitch
    Riva ECU
    Riva Grate
    4" intake
    X-Charger
    50lb injectors
    head upgrade
    Riva Exhaust
    XS intercooler
    RIVA VTS Extension Rod
    Riva Sponsons
    Riva Thermostat

    Water temp unsure (78+ tho)
    Boost unsure
    Air temp 95-99F

    So i dont have the Riva Wedge or Reduction nozzle installed yet

    suggestions?


  2. #2
    Richieb's Avatar
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    That's def low speed for that set-up.

    Make sure sponsons are up at least to middle, fill ride holes, check trim is working, rev gate is modded etc, Nozzle matched up to new output of pump... maybe a ring smaller would show what is the problem is.

    Is the prop out to a 15/22 now?

  3. #3
    Vern's Avatar
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    Wow, thats a puzzler ... I had basically the same setup last year and ran 80 - 81.5 depending on weather. I would check the troubleshooting thread for ideas and things to try ... even at 8400 rpms I could usually hit 80 on GPS. I varied rpms by swapping nozzle rings a bit.

  4. #4
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    Is anything dragging?

  5. #5
    rxpredviper's Avatar
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    Quote Originally Posted by camar0 View Post
    RXP speeds were 74mph at 8440 rpm, seems slower than expected

    mods:
    15/20 with -2 pitch
    Riva ECU
    Riva Grate
    4" intake
    X-Charger
    50lb injectors
    head upgrade
    Riva Exhaust
    XS intercooler
    RIVA VTS Extension Rod
    Riva Sponsons
    Riva Thermostat

    Water temp unsure (78+ tho)
    Boost unsure
    Air temp 95-99F

    So i dont have the Riva Wedge or Reduction nozzle installed yet

    suggestions?
    take the seat off and see what happen ! what is strange is that your rpm are good . go with a 82mm ring if you have the 15/22

  6. #6
    camar0's Avatar
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    ski pulls like a beast.... not sure...

    ride plate holes are filled
    sponsons are on lowest setting

    trim is not adj as riva messed up my ECU so not sure on spot but appears middle or +1

  7. #7
    Vern's Avatar
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    Quote Originally Posted by Danny View Post
    Is anything dragging?
    Exactly, your rpms are not terrible, and if it pulls like a beast, sounds like it is not motor, boost, or SC. Definitely look very carefully underneath the boat, pull on the intake grate to make sure it is still securely fastened, make sure that the pump shoe and ride plate are secure and not hanging low ...

    Any other symptoms like water in the hull or anything? What is the speeds & history of the ski? What I mean is what did it run before the mods, etc.

    Hate to say it, but from what you described so far, it sounds like the intake grate inserts pulled out and the grate is dragging ...
    Last edited by Vern; 06-22-2009 at 12:29 PM. Reason: oops

  8. #8
    camar0's Avatar
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    prior speeds were about 71 with no riva ecu and no xcharger

    so as of now, only +3 in speed



    i did notice some weeks ago if i left ski on the beach that it was like half flooded... unforunately only a manual bilge..... i assumed carbon ring but last ride didnt show any water in hull but then again i was flying around and back on trailer...

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