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  1. #1

    Join Date
    Mar 2008

    RXPX Optimum RPM Range

    Please help me with my ignorance,

    Ive heard that the X makes the most horsepower at 8000 rpm. My ski is running 8100 rpm. Should I put pitch in my prop to get down to 8000 rpm?

    Ive GPS'ed at 8100 rpm. Ive GPS'ed with the throttle lever rigged to only allow engine to rev to 8000 rpm.

    Top end speed is much better at 8100 rpm.... What am I failing to understand???

    Is this because the engine is not at full power with the rigged throttle lever constraint?? Do I need the engine running at full power while turning only 8000 rpm??

    A liitle help in understanding will be greatly appriceated!

  2. #2
    speedskixp's Avatar
    Join Date
    Feb 2008
    venice fl.
    yes, the peak power is @ 8000 on the X. I would invest in a reduction nozzle and use it to tune your rpms. Yes you could add pitch to the prop and bring you r's down this way also. Any thing over 8000 rpms the ecu starts pulling out timing wich is why the peak power is at 8000. If you tune your ski via nozzle or prop to 8000 you know you are getting the best possible power. The more pitch you add or the smaller the ring you put in the nozzle will add speed as long as you stay about 8000. Its like racing a car you try to hold the gear until it stops pulling then shift. Sure it can rev higher but it will not do any good because you are past peak power. But if you had a slightly taller rear end gear it can pull a faster top speed without reving as high. The adjustable nozzle and pitching the prop is like changing that gear ratio. This is even more important on a pwc because of the constant drag they have. I hope this helps.

  3. #3
    Banned User
    Join Date
    May 2008
    Lake Havasu
    Well here's where it gets interesting. I've heard that the stock ECU pulls timing out above 8000rpm. That's not necessarily a bad thing. As the temperature of the air goes up(summer), you may want a little timing pulled out of the ski to richen it up. At 8000rpm these thing tend to lean out.
    I've run mine at 8040, and 8100...both at the same temperature, and it went faster at 8100. You should run the ski around 8000rpm for max power, etc. You can either put pitch into the prop, or put a nozzle on, or both.

    How did you get your ski running 8100?? Any mods so far?? Also remember that the stock props vary in pitch, but normally are
    Progressive Pitch 13-17 over 145 degrees
    Progressive Pitch 23 degrees over the last 15 degrees, or basically 13/23.

  4. #4

    Join Date
    Mar 2008

    My mods are listed in my signature. Thanks for the input. So, what your saying is... even though max power is 8000 rpm, faster top end speed is obtained at 8100 rpm?

    Cause thats what Ive been seeing..

    Anyone else have any input on this??

  5. #5
    I got better numbers by turning 8100+ on RXP-X with the stock ECU.

  6. #6

    Join Date
    Jan 2006
    Rydal, Georgia U S A
    8040 Period!!!

    I bet I've tested impellers 400 times.... Top speed Never below 8000, and never above a few flashes 8060.

  7. #7
    8040 RPMS is the best for and RXPX

  8. #8
    mrbtd's Avatar
    Join Date
    Jul 2005
    Lindenhurst, Illinois, United States

    Any new thoughts on this subject now that it has been a couple years ? I am running a RXP-X ECU in a 2007 RXP and it really likes my 3 blade at 8060 to 8100. Dont want to fuss with the ski much so thinking I will leave it so when the summer rolls along I am @ 8000.

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