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  1. #1
    monaroman76's Avatar
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    Still not peak rpms!!

    Hey guys i think i have tried everything, but it seems everytime i go out on the p-x something is holding it back from those last few hundred rpms. The ski still feels as though it has the pickup it should, but it is struggling to get over 7840 rpms. My s/c is fine, my wear ring is brand new, my plugs are new, and my oil level is fine.
    I would think i should be turning 8000+ rpms, My max speed as per my sig was recorded about 6 months ago, while i still had the 3inch intake and FA in the manifold.
    Temperature was around 35degrees celcius last time out, but i dont think that alone would cause that much rpm loss.. Any ideas guys?
    Cheers..


  2. #2
    2006 Turbo RXP boBO's Avatar
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    What impeller are you using and
    What is slip in your charger?

    When was the last time you check the slip on your charger.

  3. #3
    monaroman76's Avatar
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    Quote Originally Posted by boBO View Post
    What impeller are you using and
    What is slip in your charger?

    When was the last time you check the slip on your charger.
    Standard impeller, and s/c rebuilt and slip set at 13in/lbs about 12 hours ago.

  4. #4
    SPEED COMES 1/10 @ A TIME SpeedFreeks Racing's Avatar
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    fuel pump..

    if you have checked everything else. i would check your fuel pump next. i have had the same type problem with a few other x's and the fuel pumps were bad. if you have a buddy with the same ski try borrow his fuel pump before you spend the money on a new one.

    just a thought

  5. #5
    richrxp's Avatar
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    Temperature changes can cause drop in rpm's

    Last year i run 8140 rpm's at 24 celicius in the Netherlands.

    I went on holiday to Spain 7960 rpm's at 36 celcius.

    That's a big loss in rpm's,which was caused by outside temps only.

    Back from holiday my rpm's were back to normal again 8140.

    Bend your prop a little ,1mm gives 100 rpm's works great and is easy to do.

    Take a look in the how to section on prop bending.

  6. #6

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    BOOST LEAK

  7. #7
    Got Boost? psycho rxp's Avatar
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    Quote Originally Posted by monaroman76 View Post
    Standard impeller, and s/c rebuilt and slip set at 13in/lbs about 12 hours ago.
    Re check your charger slip. Usually need to re check after 10hrs of break in . May need a shim, or could install Mc Master carr washers to get it back to where needed.

    Also check your oil level is not too high, should be in the middle of the 2 bends.

    Prop nose cone is on and tight

  8. #8
    check you wear ring ...if its damage it would be holding back on this few rpms

  9. #9
    monaroman76's Avatar
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    Cheers for all the input guys, i will recheck the s/c slip but i wouldnt think the slip would have dropped to the point where i was losing performance as a result, but if this is the case i have a set of mcmaster carrs that i have been too lazy to put in.. I didnt even think to check for a boost leak though, so i might double check all my hose clamps before anything else, although i would think i would notice a decrease in performance if this was the case..
    Is there way to check to make sure if the fuel pump is working okay? I dont really have the option of borrowing anyones..

  10. #10
    monaroman76's Avatar
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    Went out yesterday guys after checking all my hose clamps and tightening them a little and was able to pull to 7920 rpms, was probably about 32degrees and not sure of water temp, but being middle of summer was probable quite hot. Im thinking the lower rpms are just due to heat fade, but seems a little excessive to me..

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