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  1. #1
    Phil's Avatar
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    RXT-X Lost rpms today

    I let my friend try my RXT-X today for 20 minutes. When he came back in from his run, all I could get was 7,920rpms. Normally, I get 8,040rpms. Has anybody lost rpms on their ski?


  2. #2
    MPower's Avatar
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    Quote Originally Posted by Phil View Post
    I let my friend try my RXT-X today for 20 minutes. When he came back in from his run, all I could get was 7,920rpms. Normally, I get 8,040rpms. Has anybody lost rpms on their ski?

    heat fade probably. thats a pretty small change in RPM.

  3. #3
    Phil's Avatar
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    Quote Originally Posted by MPower View Post
    heat fade probably. thats a pretty small change in RPM.
    It hasn't done this before in similar conditions. It was a perfect day for jet skiing. A little windy, but it was sweet. Also, remember when I was running it before he tried it, I was getting 8,040 several times and hitting 69-70 on the dream-o-meter.

  4. #4
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    Phil, you are talking about 120 rpm's. A 1.5% drop. Heat fade, realitive humidity, wear ring wear, etc.

  5. #5
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    That's not really that much of a change. I wouldn't be worried

  6. #6
    Phil's Avatar
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    Quote Originally Posted by NCHeel View Post
    Phil, you are talking about 120 rpm's. A 1.5% drop. Heat fade, realitive humidity, wear ring wear, etc.
    OK, but I had just driven the ski at 8,040 about 20 minutes before the rpms dropped. Also, don't you think that the ski should be red lining at 8,040 all the time with that prop? Now it kind of tells me that I really can't go with a larger prop until I max it out at 8,040. Especially since the weather will be getting worse every week until mid July when it is absolutely horrible with humidity and heat. Before I start adding performance items I have to get to the bottom of this. Then I can add an air intake, exhaust, nozzle etc. etc. Oh, I forgot to mention that I only have 2 hours on the ski.


    You know now that you mention it, I did see some rain clouds just before I put the ski away. It is possible that the humidity went South in the short period of time I was out running around. It happens. Let's hope that was the case. I will try it again today. When I get on it, I only stay on it for about 7 seconds and get off.

    The reason that this upsets me is because I feel that I finally got a fast ski! My T-X hit 70mph @ 8,040 on the dream-o-meter on the first few pulls after I putted around for about 10 minutes. I broke it in using Jerry's technique. Most of the time when I buy a ski it always turns out to be the slowest ski of its kind around. The only reason that I win grudge races on my lake is because I am not afraid to stay in it when it gets nasty. The young kids (16-24) just don't seem to have the guts or experience... or maybe it's because I am a little nuts.

    Oh well, thanks for helping guys,

    Paranoid Phil
    Last edited by Phil; 04-12-2008 at 08:57 AM.

  7. #7
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    Phil I think I remember that conversation about you "babying" ski's during breakin. 2 hours let her rip, but not more than 30 seconds. At 5 hours she will be broke in fully if the ecu is not holding back (which some think it is). You will not see full rpm's with the stock air intake. I never did on my RXT till going to the 4". A ding in the prop could drop rpm's that much. I think Jerry said that these ski's should be dialed in for 8000 rpm anyways because above that the ecu cuts engine power.

  8. #8
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    Here you go from the horses mouth


    Quote Originally Posted by Green Hulk View Post
    Guys, everything we have learned in the past in regards to RPM was to pitch accordingly to run 8100 RPM's with the stock ECU.

    This is NOT the case for the X models. In fact, ideal RPM for these machines is no more than 8000 with the stock ECU.

    My sources informed me that the most power is made at 8000 RPM's. Any higher than that timing is reduced aggressively. There is also a hard rev limiter on the X models which is set at 8200.

    I just wanted to post this up as i know many of you with X models have been depitching to achieve 8100 RPM's.

    This only pertains to the X models and not the 08 215 HP versions.

  9. #9
    Phil's Avatar
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    Quote Originally Posted by NCHeel View Post
    Phil I think I remember that conversation about you "babying" ski's during breakin. 2 hours let her rip, but not more than 30 seconds. At 5 hours she will be broke in fully if the ecu is not holding back (which some think it is). You will not see full rpm's with the stock air intake. I never did on my RXT till going to the 4". A ding in the prop could drop rpm's that much. I think Jerry said that these ski's should be dialed in for 8000 rpm anyways because above that the ecu cuts engine power.
    This is good news in a way. How many more rpms do you think I will see at 5hours? 10 hours? Again, how many rpms do you think I should pickuip with a 4"? If I can pick up another 500 rpms total then I know that I can go with a taller prop and I iwlll plan for that.

    Also, I will check my prop for dings.

    Thanks,

    Phil

  10. #10

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    Phil, don't worry every best speed I've gotten is @ 8040.

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