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  1. #1

    Okay prop tuning experts for my 2012 rxpx

    Stock prop with mods 73 mph 8250 max rpm with vtech tuning. Now 15/20r prop and getting 74mph with only 7780 rpm. Tuning my own prop. Which side do I need to change and how much to get in the 8100 range. Trailing edge or leading edge and by how much ?

    Looking for more speed top end


  2. #2
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    Bend rear of blades towards the front of the impeller.
    Start with about 1.5mm-2mm.

  3. #3
    Moderator Snoman's Avatar
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    First off What mods do you have on your boat???I noticed you stated you had a V-Tech tune but then said your trying to get into the 8100 RPM range...SO what RPM are you looking to get????

    Rule of thumb,If you need more RPMs bend the trailing edge towards the front of the prop..IF you need less RPMs bend the trailing edge toward the back of the prop...

  4. #4

    prop bending

    Quote Originally Posted by Snoman View Post
    First off What mods do you have on your boat???I noticed you stated you had a V-Tech tune but then said your trying to get into the 8100 RPM range...SO what RPM are you looking to get????

    Rule of thumb,If you need more RPMs bend the trailing edge towards the front of the prop..IF you need less RPMs bend the trailing edge toward the back of the prop...
    mods i have are 4 inch kanaflex. Vtech 8250 tune, Exhaust out rear of ski and 15/20r prop thats all

    I thought trailing edge was the last edge that the water touches when on the ski and leading edge is the edge water first touches when running.

    I am 74mph currently with 15/20 prop only 7780 max rpm. I figured i would make it a 15/19 to go faster. Is this wrong?

    sorry i am new to prop tuning and pitch/etc.

  5. #5
    skigolfnut's Avatar
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  6. #6
    Bounty Hunter Carlos Thomas's Avatar
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    Quote Originally Posted by budman5201 View Post
    Quote Originally Posted by Snoman View Post
    First off What mods do you have on your boat???I noticed you stated you had a V-Tech tune but then said your trying to get into the 8100 RPM range...SO what RPM are you looking to get????

    Rule of thumb,If you need more RPMs bend the trailing edge towards the front of the prop..IF you need less RPMs bend the trailing edge toward the back of the prop...
    mods i have are 4 inch kanaflex. Vtech 8250 tune, Exhaust out rear of ski and 15/20r prop thats all

    I thought trailing edge was the last edge that the water touches when on the ski and leading edge is the edge water first touches when running.

    I am 74mph currently with 15/20 prop only 7780 max rpm. I figured i would make it a 15/19 to go faster. Is this wrong?

    sorry i am new to prop tuning and pitch/etc.
    I thought that was the right prop for the "Stage 1" mods you have. From what I have seen/read, you should be at close to the limiter with those MODS. Your 500 RPM's off. That is a big swing. Most people have the 8350 tune with that prop are are right on. And that is almost 600 RPM's over what you are getting. Hmmm. I would love to hear what the issue/solution is.

  7. #7

    speed

    Quote Originally Posted by Carlos Thomas View Post
    Quote Originally Posted by budman5201 View Post
    Quote Originally Posted by Snoman View Post
    First off What mods do you have on your boat???I noticed you stated you had a V-Tech tune but then said your trying to get into the 8100 RPM range...SO what RPM are you looking to get????

    Rule of thumb,If you need more RPMs bend the trailing edge towards the front of the prop..IF you need less RPMs bend the trailing edge toward the back of the prop...
    mods i have are 4 inch kanaflex. Vtech 8250 tune, Exhaust out rear of ski and 15/20r prop thats all

    I thought trailing edge was the last edge that the water touches when on the ski and leading edge is the edge water first touches when running.

    I am 74mph currently with 15/20 prop only 7780 max rpm. I figured i would make it a 15/19 to go faster. Is this wrong?

    sorry i am new to prop tuning and pitch/etc.
    I thought that was the right prop for the "Stage 1" mods you have. From what I have seen/read, you should be at close to the limiter with those MODS. Your 500 RPM's off. That is a big swing. Most people have the 8350 tune with that prop are are right on. And that is almost 600 RPM's over what you are getting. Hmmm. I would love to hear what the issue/solution is.
    I know I agree. If the speed was off or down then i would think first there was a problem. But I am at 74 mph and it screams up to that speed. So no engine lack of power issues at all. Water temp was cold for here in az at 60 degrees and air temp was 70.
    Only thing I can come up with is that my prop isnt really a 15/20, but thats what it says on it. When I pull it off I will check it with the pitch gage. Maybe manufacturing of the prop was Monday morning poor quality.

  8. #8
    monaroman76's Avatar
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    There is nothing wrong at all. You just have too much pitch. There can be significant variances with 2 different 15/20 props out of the box, so you can't compare your setup to someone else's. Your speed is good for those rpms like you say, so go ahead and remove a couple of mm. You will pick up a few hundred rpm and be over 75 no problem. Acceleration will also improve noticeably.

  9. #9

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    i had the same issue over the summer:

    http://www.greenhulk.net/forums/showthread.php?t=183868&page

    repitch from erik at speedfreeks set me straight.

  10. #10
    Bounty Hunter Carlos Thomas's Avatar
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    If someone orders a 15/20r that prop should be a 15/20r. If I ordered a prop and it was not spot on, it would go back. If I wanted to bend, I would bend my own prop. Don't accept sloppy prop work.

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