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  1. #1

    Join Date
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    Upgrade Prop or Pitch?

    I am less than a month away from de-winterizing the skis. You can look at my sig for my upgrades and with them and the 14/19 I was hitting the rev limiter during the hot months, I'm sure when I take it out next month with cool air and water I will be hitting the rev limiter much easier. My question is with these mods should I upgrade to a 15/20 or three blade or should I jus pitch the 14/19 to 8100 RPM?


  2. #2
    Site Admin Green Hulk's Avatar
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    Stick with the 14/19R but add the Riva adjustable venturi nozzle and run the 81mm ring

  3. #3

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    So adding the nozzle and 81mm ring replaces the need to pitch and will keep me ~8100RPM?

  4. #4

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    Jerry, approximately how many rpm is 1 mm of nozzle size worth?

  5. #5

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    Jul 2006
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    Indian Lake Ohio
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    Quote Originally Posted by engineermike View Post
    Jerry, approximately how many rpm is 1 mm of nozzle size worth?

    From what I have found 1 mm equals around 100 rpm

  6. #6

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    Quote Originally Posted by Lake rat RXP View Post
    From what I have found 1 mm equals around 100 rpm
    Unbelievable. So now. . .

    1 turn on the wastegate = 1 psi boost = 100 rpm = 1 mph = 1 mm on the nozzle = 1 mm on the prop trailing edge

    Are we charmed?

  7. #7
    AKA: Larry lafjax's Avatar
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    Jacksonville, Fl
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    Quote Originally Posted by Lake rat RXP View Post
    From what I have found 1 mm equals around 100 rpm
    I'm only seeing 50 rpm's per millimeter.

  8. #8

    Join Date
    Jul 2006
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    Indian Lake Ohio
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    I did a search and found two threads where people were gaining 100 rpm per 1mm, I am sure that conditions and mods will effect this though.

  9. #9
    ou812's Avatar
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    I get 80-100 rpm per mm in fresh, 100-120 less per -mm in salt.

    When talking with skat I was told 1mm = about 75 rpm.. so salt & fresh water would tell the difference...
    Last edited by ou812; 02-19-2008 at 07:15 PM.

  10. #10

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    Jan 2006
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    Rydal, Georgia U S A
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    Usually 50-70 rpms.

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