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  1. #1
    Greggpru's Avatar
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    Rpm gain I'm cooler water/air temp?

    I'm currently hitting between 8650-8750, I was going to repitch the prop to bring rpm up a 100-150, but being that I am gonna ride till the end of October when air and water temp will be significantly cooler I'm debating on just leaving it alone . My question is what approximate rpm change will I see in 60-65 degree air/water Temps as compared to 80-85 air/water Temps I'm riding in now. Should I just leave it where it is?


  2. #2
    JFizzleJR's Avatar
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    My advice is to look up an air density calculator and play around with the numbers to see HP gain/loss. It's probably a 200 RPM difference between the conditions you mentioned.

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  4. #3
    Sanfish's Avatar
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    You could adjust prop to gain the rpm now, then use an L13 cone when winter air hits (it will lower rpm) and this way you don't have to screw around with props.

  5. #4
    Mothman's Avatar
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    On a 9000rpm tune you wanna shoot for 8800ish so you're already close. Cooler air will put you very very close if not on the limiter, so an L13 would help you reign in the gain to keep it around 8800. That or reduce venturi diameter by 1mm when cooler air/water hits.

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    Greggpru's Avatar
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    If i install the 13 with no spacers will my rpm still drop compared to the stock cone?

  7. #6
    Sanfish's Avatar
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    Quote Originally Posted by Greggpru View Post
    If i install the 13 with no spacers will my rpm still drop compared to the stock cone?
    Yes (maybe between 70-100rpm).

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  9. #7
    Greggpru's Avatar
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    Quote Originally Posted by Sanfish View Post
    Quote Originally Posted by Greggpru View Post
    If i install the 13 with no spacers will my rpm still drop compared to the stock cone?
    Yes (maybe between 70-100rpm).
    Can i bore my nozzle to gain it back? And how many mm?

  10. #8
    Mothman's Avatar
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    Pitch the trailing edge instead of boring a nozzle.

  11. #9
    Sanfish's Avatar
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    Quote Originally Posted by Greggpru View Post
    Quote Originally Posted by Sanfish View Post
    Quote Originally Posted by Greggpru View Post
    If i install the 13 with no spacers will my rpm still drop compared to the stock cone?
    Yes (maybe between 70-100rpm).
    Can i bore my nozzle to gain it back? And how many mm?
    I don't know what bore size you are at now but on the 83mm nozzles, the Lucky 13 instructions recommended you bore +3mm. This is mostly to do with gaining back the RPM loss from adding the L13. I left mine at 83mm and yields best speed and I needed to drop RPM a little.

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  13. #10
    Greggpru's Avatar
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    Gonna order the lucky 13 and then adjust my rpm , thanks guys
    Last edited by Greggpru; 09-09-2016 at 12:15 PM.

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