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  1. #1

    what is the exit and steerring nozzle size range differences, min and max?

    we all know the OEM plastic steering nozzle is 92mm round, and the SHO oval nozzle is 90x86.
    when using the sho nozzle on the 85mm venturi nozzle the steering felt good, not as sloppy as the 92 OEM.

    I had bored the SHO nozzle to 91x87.5 and tried it with the a 87mm nozzle and the steering was so tight, if you sneezed and jerked the bars you were going off the ski...

    so I would like to taylor a nozzle for tight steering.
    what is the optimal size steering nozzle for the 87mm exit nozzle?

    what would be the minimum and maximum range?

    GPR:
    85mm ho pump > 92mm OEM steering = total of 7mm difference. 3.5mm larger diameter overall. (sloppy steering feel)
    87mm > 92mm OEM steering = total of 5mm, 2.5 larger diameter overall. (tighter steering feel)
    87mm> 91x87.5 bored sho nozzle, very tight, very twitchy...

    IMHO the SHO nozzle stock and not bored gave very good steering feel and turning control compared to stock. But when boring the nozzle to 91x87.5 with the 87mm venturi , the steering was downright scary... but perfect for carving turns...

    I would think if the math were reversed that say an 93-94mm steering nozzle with an 87mm venturi would be way sloppy..., even tho this would "be" the size if Yamaha had made a nozzle 7mm oversize for the 87mm.

    ld like to hear some feedback on this. I want a tighter steering feeling like what the sho nozzle did for the 85mm. I would think that a 90mm round steering nozzle would do the trick...
    I could take out another mm on the SHO and give that a whirl...

    any thoughts? Thanks...


  2. #2

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    Quote Originally Posted by AndyGPR View Post
    we all know the OEM plastic steering nozzle is 92mm round, and the SHO oval nozzle is 90x86.
    when using the sho nozzle on the 85mm venturi nozzle the steering felt good, not as sloppy as the 92 OEM.

    I had bored the SHO nozzle to 91x87.5 and tried it with the a 87mm nozzle and the steering was so tight, if you sneezed and jerked the bars you were going off the ski...

    so I would like to taylor a nozzle for tight steering.
    what is the optimal size steering nozzle for the 87mm exit nozzle?

    what would be the minimum and maximum range?

    GPR:
    85mm ho pump > 92mm OEM steering = total of 7mm difference. 3.5mm larger diameter overall. (sloppy steering feel)
    87mm > 92mm OEM steering = total of 5mm, 2.5 larger diameter overall. (tighter steering feel)
    87mm> 91x87.5 bored sho nozzle, very tight, very twitchy...

    IMHO the SHO nozzle stock and not bored gave very good steering feel and turning control compared to stock. But when boring the nozzle to 91x87.5 with the 87mm venturi , the steering was downright scary... but perfect for carving turns...

    I would think if the math were reversed that say an 93-94mm steering nozzle with an 87mm venturi would be way sloppy..., even tho this would "be" the size if Yamaha had made a nozzle 7mm oversize for the 87mm.

    ld like to hear some feedback on this. I want a tighter steering feeling like what the sho nozzle did for the 85mm. I would think that a 90mm round steering nozzle would do the trick...
    I could take out another mm on the SHO and give that a whirl...

    any thoughts? Thanks...
    For best results you need the stearing nozzle 5mm larger than the reduction nozzle is what I use. I had a stainless insert installed in to the back of my SHO stearing nozzle and it is now round inside and 5 mm larger than the reduction nozzle size, Tommy Jordan

  3. #3
    AWA Member 32DegH2O's Avatar
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    Quote Originally Posted by 2fast4u View Post
    For best results you need the stearing nozzle 5mm larger than the reduction nozzle is what I use. I had a stainless insert installed in to the back of my SHO stearing nozzle and it is now round inside and 5 mm larger than the reduction nozzle size, Tommy Jordan
    Is this what you would use if you were looking for top end speed?...or would you make it a bit bigger?

  4. #4
    this mornings findings:
    the 92mm OEM nozzle is still to loose for my liking... with everything else being correct, will a tighter nozzle reduce speed or RPM?

  5. #5
    slowteg97's Avatar
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    hey andy i think a tighter nozzle when thinking about thrust and propulsion andtaking into concideration of the amount of water your pump can actually flow at max. will all come into account i know u and i had a brief talk about it when we met, but where ever you are right now with ur current set up reducing the steering nozzle is gonna increase your thrust due to back pressure in the pump stator. with a smaller nozzle a smaller nozzle will more then likely result in a ski that a rocket out of the whole and have increased mid range feel, but your top end might suffer due to the fact that now your cutting down how much you pump can exhaust through that steering nozzle. now another thing thats gonna come into play and the reduction nozzle like : angle, how tall the vein guides are or if theres even any inside and the size that nozzle is reduced to... very confusing stuff basicly for guys like us its trial and error and constant gps runs to help understand the effects of every little thing changed in the pump. my best advice is dont do multiple things at once because youll never know what effected the other ya know. i did read your build thread and saw u did do some stator work and i saw you did
    other stuff along with that so its hard to know if you made any gains on just cleaning up the stator. this is a topic that could literally go on for daysssssss lol cause theres so many things that are subject to change just by altering 1 thing in that pump. give me a ring maybe we can hatch an idea and see what we can figure out

  6. #6

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    Quote Originally Posted by AndyGPR View Post
    this mornings findings:
    the 92mm OEM nozzle is still to loose for my liking... with everything else being correct, will a tighter nozzle reduce speed or RPM?
    I have done lots of R&D on nozzles 5 mm larger than your reduction nozzle is the best all round you can do ! I bet you have a 85 mm reduction nozzle and a 92 stearing nozzle = 7 mm differance which will feel loose. A bonus also if you use the 5 mm rule your trim handle has more effect on the ski when you go from neutral to up or down trim also! Any thing less than 5 mm diff. and you will start to loose top speed too! Tommy Jordan
    Last edited by 2fast4u; 07-25-2010 at 04:54 PM. Reason: added more info

  7. #7
    hey Basil! whasssup!

    I haven`t done any stator work on the pump. just trying different exit nozzles. The 85mm likes the stock sho steering nozzle...
    I didn`t try it when it was 90x86 oval on the 87mm exit nozzle bc i knew it was already to small...

    anyways, I rode early this morning with the OEM 92mm plastic nozzle, and it was still somewhat loose, although normal, as that is what came with the ski...
    sooo I bored the oval SHO nozzle more to 92mm x 90.+mm and will try that next time out...
    hopefully we have a winner...

  8. #8
    Quote Originally Posted by 2fast4u View Post
    I have done lots of R&D on nozzles 5 mm larger than your reduction nozzle is the best all round you can do ! I bet you have a 85 mm reduction nozzle and a 92 stearing nozzle = 7 mm differance which will feel loose. A bonus also if you use the 5 mm rule your trim handle has more effect on the ski when you go from neutral to up or down trim also! Tommy Jordan
    Hi Tommy, I had been using an 87mm exit nozzle last few rides to get rpm`s up, so far so good... The SHO oval nozzle in stock form worked great with the 85mm. knowing that sho nozzle would be to small, I put the OEM plastic 92mm back on for this mornings ride. When I got home I bored out the SHO nozzle more for use with the 87 but kept it on the tighter side... room for adjustment...

    Tommy, I`m also using the Riva lever drop nozzle kit, I love it!!!
    Last edited by Pale Rider; 07-26-2010 at 09:17 PM. Reason: spelling

  9. #9

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    I contacted Skat-trak about this issue years ago since they have venturis and swing buckets with adjustable thrust rings. They recommended a 3-4mm difference. If it is to loose, then the turn is sloppy and if to tight, it becomes physically to hard to turn (like in endurance races), and it is very sensitive or stiff in the steering. As it was explained to me.... we are not trying to deflect the whole thrust to make it turn, just part of it. The point is that they would be a good source of R/D info.


    Three mm difference works well for me. Your needs may vary.

  10. #10
    The bored SHO nozzle to 92x90mm is the sh-t!
    The ski turns awesome without the feeling of it being to tight, it`s just right! It`s predictable and goes where I want it to...

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