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  1. #1
    asphalt, dirt, and water are my playgrounds. ViperRy's Avatar
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    Speadfreaks impeller set back mod

    Anyone had this done? Any gains over a standard repitch? I have a rude1 ski and need to repitch a 15/20 4 blade. I was thinking of doing it myself but it would be my first attempt at repitching a prop.


  2. #2
    Quote Originally Posted by ViperRy View Post
    Anyone had this done? Any gains over a standard repitch? I have a rude1 ski and need to repitch a 15/20 4 blade. I was thinking of doing it myself but it would be my first attempt at repitching a prop.
    sending your prop to eric at speedfeeks is money well spent.

  3. #3
    homebrew's Avatar
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    eric with speedfreaks repaired --repitched and did the set back on my impeller --went from a 15/20 to a 12/21.5 with the set back and it is doing great --staying around 8000 to 8100 rpms depending on the weather --i can't give you the gains because i was on the rev. limiter before that --i had 3 things done at once and eric did a super fast turn around

  4. #4
    West Texas RXP skoepp's Avatar
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    Quote Originally Posted by rotax racing View Post
    sending your prop to eric at speedfeeks is money well spent.
    +1, be sure and get some good data on rpm/conditions so Eric can best pitch your prop or anyone for that matter.

  5. #5
    KC Blue Thunder's Avatar
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    OK ...I'll bite, whats it suppose to do.

  6. #6
    Moderator Snoman's Avatar
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    Quote Originally Posted by Blue Thunder View Post
    OK ...I'll bite, whats it suppose to do.
    It sets the blades back closer to the pump veins allowing a lesser chance of air to get between the blades and the veins...Therefor moving the water more efficiently through the pump......IF i am right...Which im sure im off a tad...But this is what ive been told...

  7. #7
    KC Blue Thunder's Avatar
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    Quote Originally Posted by Snoman View Post
    It sets the blades back closer to the pump veins allowing a lesser chance of air to get between the blades and the veins...Therefor moving the water more efficiently through the pump......IF i am right...Which im sure im off a tad...But this is what ive been told...
    Thanks Scott.

  8. #8

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    putting the back of the blades tight to the pump veins is the same as having a tight impeller to wear ring tolerance - less blow by - if there is any air in the pump it will be pushed thru the veins faster in a single vein rather than cavitate between them. As they say in racing - every little bit helps - will you notice any gain? Too many factors to say. Go for it.

  9. #9
    formerly Gold06RXP Turbo Nick's Avatar
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    Only thing is that if you have a real steep prop (like me) you cant do the set back. With a 24 or 25 pitch prop the blades are already very close to the stater. If you would machine the prop to move it closer it will hit the stater. But it will definatly work if you have a 22 or less pitch prop.
    Quote Originally Posted by Snoman View Post
    It sets the blades back closer to the pump veins allowing a lesser chance of air to get between the blades and the veins...Therefor moving the water more efficiently through the pump......IF i am right...Which im sure im off a tad...But this is what ive been told...

  10. #10
    R88ory RXP's Avatar
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    Quote Originally Posted by GOLD06RXP View Post
    Only thing is that if you have a real steep prop (like me) you cant do the set back. With a 24 or 25 pitch prop the blades are already very close to the stater. If you would machine the prop to move it closer it will hit the stater. But it will definatly work if you have a 22 or less pitch prop.
    I had to file the tips of my 13/21 with a 3mm set back, it was hitting the housing just behind the wear ring. R88

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