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  1. #1
    J_Dolla's Avatar
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    Slowwwwwwww gprxp



    Ok guys I put this ski together at the end of last summer and only ride it a handful of times but I feel something is holding this thing back . Fastest I could get it to go was 80.2 @ 8050-8100 RPM
    Ski idles fine and the motor is snappy It just seems this thing is SLOWWWWWW.
    MODS are as follows
    2005 rxp motor
    XS intercooler
    50 lb injectors
    Riva racing ECU
    2 rude charger
    Rrfpr
    4" intake
    Riva free flow 1300 exhaust pipe
    Wb2
    Pump is a 2003 gp1300r with solas concord 14/20 untouched
    R&D 800 grate
    R&D ride plate
    Stock plastic trim tabs


  2. #2
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    Knock sensor installed?

    How are you monitoring AFR's?

  3. #3
    Moderator Insanediego Joe's Avatar
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    he is turning 8100 rpms and making power. this is a handling issue. post pics of ride plate and pump shoe. what is your ride plate angle set at?

  4. #4
    Moderator Insanediego Joe's Avatar
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    14/20 prop seems small for your set up...are you sure your not banging the rev limiter? you should be turning a 15/20

  5. #5
    YudLuz2's Avatar
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    Quote Originally Posted by J_Dolla View Post


    Ok guys I put this ski together at the end of last summer and only ride it a handful of times but I feel something is holding this thing back . Fastest I could get it to go was 80.2 @ 8050-8100 RPM
    Ski idles fine and the motor is snappy It just seems this thing is SLOWWWWWW.
    MODS are as follows
    2005 rxp motor
    XS intercooler
    50 lb injectors
    Riva racing ECU
    2 rude charger
    Rrfpr
    4" intake
    Riva free flow 1300 exhaust pipe
    Wb2
    Pump is a 2003 gp1300r with solas concord 14/20 untouched
    R&D 800 grate
    R&D ride plate
    Stock plastic trim tabs


    Your problem is your old style pump and concord prop. That setup makes good speed to around 7300 rpms and then it falls off a lot. That's about the same speed and rpms my triple pipe motors ran with that setup. Updating to the newer 05 high flow pump and using a stock 14/20 Dynafly increase the speed by about 6 mph over the old setup when turning over 8100 rpms. The Dynafly 14/20 is much faster in the midrange and easier to pull on top. So if you are wanting to keep your rpms the same, a 14/21 or 14/22 will give you a little more speed. Make sure you use a 5 degree 85mm nozzle with the newer style pump.

  6. #6
    J_Dolla's Avatar
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    The knock sensor is installed and it had the resistor in the harness. Monitoring a/f with innovative MTXL tapped manifold WOT is 11.8-11.9
    I'm not sure about the ride plate it is against the hull with no washers(how do I measure the angle and what should it be?)

  7. #7
    J_Dolla's Avatar
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    I had no idea that the 05 pump was that much better. I thought it was only like +1 mph faster over the non H.O. Pump

  8. #8
    J_Dolla's Avatar
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    I'm also looking to get up close to the 8650 limiter .

  9. #9
    YudLuz2's Avatar
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    Quote Originally Posted by J_Dolla View Post
    I had no idea that the 05 pump was that much better. I thought it was only like +1 mph faster over the non H.O. Pump
    The old test that people post are using single pipe GPR's turning 7100 to 7300 rpms. Its only about a 2mph gain at that rpm. When you test the new pump
    at over 8100 rpms with the Dynafly prop you see big numbers compare to the old setup. Try it at a 14/20 if you want to get a few more rpms with the new pump setup. The old concords can be really big out of the box, but you could still be missing some rpms with your setup.

  10. #10
    J_Dolla's Avatar
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    So just curious should I take a few mm off the back of the prop to get the rpm up and get more speed out of it?

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