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  1. #1
    Member Wave to Wave's Avatar
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    Gearcase modification, more speed

    We did an article recently about gearcase design, and how they can be modified for improved dynamics. Typically, nosecone kits are too pointy, so if you simply round the tip, you can improve the water flow. So, we tested it out on our Allison Grand Sport with a 150 Mercury four stroke. It has a customized nosecone that someone did for us, and it was too pointy. We blueprinted it by rounding out the tip, smoothing the leading edge, and redoing the edge of the skeg. We improved our top speed, and are now on the rev limiter. 77 MPH at 5940 RPM.

    Here are links to the articles, one about gearcase design, and one about the Allison. The rounded tip is beneficial at faster speeds too, and can prevent blowout over 100 MPH.

    https://www.wavetowave.com/home/2019...our-lower-unit


    Here is the article where we did the modification to our 150
    https://www.wavetowave.com/home/2019...cation-testing

    .
    [url=https://flic.kr/p/Rvo6rZ]Allison Merc 150

  2. Member Wave to Wave's Avatar
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    #2
    Here's a link to the Video of testing it out.


  3. Member turfy49431's Avatar
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    #3
    Thats haulin azz with a onefiddy
    Ranger R81VS, Mercury 175EFI w/ 25 Tempest

  4. BBC SPONSOR/ Shallow Water Anchors Moderator
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    #4
    940 lbs..wish my ranger weighed that lol

  5. Member cajunrgfm's Avatar
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    #5
    346.jpgthere's the prop you mention,trophy,allison cut and pitched to 29,great fishin prop, ,80mph@5400 cruise speed on my xb2003,,but I can turn it to 6700 with modified 250xb,,,alot of guy's flattened the nose on the old 2.4/2.5 lowers,,it's all about water flow around the case,works for some,not for others,but I think your on the right track.

  6. Member cajunrgfm's Avatar
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    #6

  7. Member
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    #7
    Quote Originally Posted by cajunrgfm View Post
    The attachments do not work.

  8. Member cajunrgfm's Avatar
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    #8
    Quote Originally Posted by 1Holeshot View Post
    The attachments do not work.
    Wonder why,they showed as pics,then to a hyperlink the deadlink,

  9. Member Wave to Wave's Avatar
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    #9
    Hoping to try a 30" ProMax and Hydromotive soon. And will raise the engine slightly. Should get to 81 to 82.

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