Ftn ?
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Ftn ?

  1. #1
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    Default Ftn ?

    Is their a rule of thumb for changing nozzle sizes?Does the bigger impellers and horsepower need a bigger nozzle?I understand that a smaller nozzle creates higher bowl pressure,lower volumn and higher velocity.
    Also i assume the smaller opening would help raise intake pressure on the big end?
    What's your reason for changing them?
    I'm in the 900 + hp range.

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  3. #2
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    from what I have read, the smaller nozzle size helps for more mph on the top end, but hurts your hole shot but its saturday and all the smart/fast guys are out on the lake, haha.... they can tell ya more about it. sounds like ya have enough hp to get it out of the hole, try a smaller one and see if ya pick up some mph.....just my 1 cent.

  4. #3
    Senior Member H20MOFO's Avatar
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    Quote Originally Posted by Adam View Post
    from what I have read, the smaller nozzle size helps for more mph on the top end, but hurts your hole shot but its saturday and all the smart/fast guys are out on the lake, haha.... they can tell ya more about it. sounds like ya have enough hp to get it out of the hole, try a smaller one and see if ya pick up some mph.....just my 1 cent.
    Last time this came up ...fwiw...I said a comment like"I doubt a ftn will make a difference that you can feel by the seat of your pants" Someone then corrected me and told me it helped they're holeshot enough he could feel the difference.
    Another Hot Boat refugee

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  6. #4
    bfp
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    basically the smaller I.d. will improve the leave, but will not help top end at all, unless you are running out of water at the top end. if that's the case then shoe depth, and or bottom blue printing should be addressed. how heavy is your boat? do you have an inducer? impellor cut? try different incerts to find what your boat likes. if you need a better leave go with a smaller id. if it leaves hard,go bigger. you will feel a difference.

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    sounds like I was 180 degrees off,lol. I know I have read that before, its just boats, every one is different! sounds like you have some good hardware to work with, good luck.
    Last edited by Adam; 08-29-2010 at 10:29 AM.

  8. #6
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    Quote Originally Posted by bfp View Post
    basically the smaller I.d. will improve the leave, but will not help top end at all
    Agreed, I needed a bit more out of the hole with our Daytona. I went to a smaller nozzle and it cleaned up the launch quite a bit, but I lost 3 mph in the traps.

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    Senior Member speedealer's Avatar
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    I made a .060 nozzle change on a 17 placecraft with a 760hp 496 and went from 10.40 to 10.02. Probably over charging the pump with small nozzle. Also helped settle the boat down on top half of the track.

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    looks like they are worth playing around with.Thanks everyone for the info.

  11. #9
    Senior Member Futs's Avatar
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    Quote Originally Posted by speedealer View Post
    I made a .060 nozzle change on a 17 placecraft with a 760hp 496 and went from 10.40 to 10.02. Probably over charging the pump with small nozzle. Also helped settle the boat down on top half of the track.
    Did you go smaller? what sizes did you start with and end with?

  12. #10
    Senior Member speedealer's Avatar
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    Quote Originally Posted by Futs View Post
    Did you go smaller? what sizes did you start with with and end with?
    We started with a 3.060 and went to 3.125. Boat ran 3 10.40 before the change and 4 10.02 after the change. stopped at 3.125 . we were running m/e so we made no more changes.

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