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Thread: Nozzle size

  1. #1

    Nozzle size

    I have been reading alot about 85mm and 87mm nozzles.
    The 87mm has better holeshot, has anyone tried boring it out bigger than this? Is it even possible and what would be the pros and cons of doing this?


  2. #2
    Hydrotoys's Avatar
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    You may/maynot be on to something. I'm sure there has been limited work on this, but I don't recall reading any comparison results.

    I DO know that with the wetwolf AAT, it makes a huge difference on top speed, and accleration. A bored nozzle with the AAT makes way more sense than losing top end, or losing bottom end.

  3. #3
    Johnjet's Avatar
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    we had a 14/20 prop seize on a 1200r stock race boat, found it to tall in testing so rather then destroy the prop, bored out nozzle from 87-89mm and found another 1-2mph

  4. #4
    Was it only top speed improved or did you find any difference in holeshot?

  5. #5
    Johnjet's Avatar
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    there were gains every where

  6. #6
    It's just another part of tuning - prop pitch, cone size, nozzle size, pump - they all have to matched (to the hp your motor is putting out) just right to get the most benefit. No one size works best kind of answer.

  7. #7
    I guess then if the pump was bored out you would need a taller prop, but you might not have the hp to turn it(depending on your mods). So you might not see any gains.
    Thanks for the info.

  8. #8
    Johnjet's Avatar
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    85mm with 5 degree ? 05 gpr
    87mm with 5 degree ? 00 gpr

    85mm with 3 degree ?
    87mm with 3 degree ? xlt1200


    the 87mm with 3 degree would be choice for c/c racing ?

  9. #9
    Got my stock 85mm nozzle bored out to 87mm its 5 degree up.
    Running a 13/20 solas, with the 85mm the ski did not pull full revs through small chop ( always drooping about 30-70 rpm) as it would flat calm, but with 87mm it pulls an extra 40-50 rpm on top of the 7100rpm plus it pulls through the chop without dropping.
    87mm seems to work alot better with 13/20.

    05 1300

  10. #10
    Johnjet's Avatar
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    is the 3 degree the way to go or 5 degree ?

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