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  1. #1
    fabrication guru rapidacceleration's Avatar
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    YAMA-D00 SUV 1500SC first test day results

    YAMA-D00 SUV 1500SC first official test day results.

    The setup
    stock 185hp SC 4tec motor
    megasize external IC
    open loop cooling kit
    RR overdrive gear set (same boost as RXP)
    stock 03 ECU (7650 limiter)
    stock gtx fuel pres reg
    stock 01 yamaha 155mm pump
    new "out the box" riva 15-21 concord setback prop.
    crazy scoop grate (1st thing comeing off)

    unfortunatly the result were NOT as i exspected them to be
    but there alot of adjusting and tweeking that need to be done..
    anyway the results were 60.7MPH @ 7300RPM....

    Im in need of some serious pump and hull tweeking advise here. nothing lines up in the back, all the rideplate,shoe,grate,etc all are at different levels, and i know the megascoop is mega scrubbing speed.

    Here my baseline numbers
    now get me over 70MPH boys
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  2. #2
    You have to get as much of that big hull out of the water as possible. The SUV basically uses all the same pump components as the XLT. Mods like a 5 degree nozzle, one of our modded rideplates. The ho pump would be the way to go, but i saw in a previous post your looking to retain the old style pump for now.---TRY A NU-JET!!! We built some seriously fast XLT's running the Nujet in the old pump setups-- they work real well with the heavier hulls.

  3. #3
    EZ Dock of Long Island Shibby1485's Avatar
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    Daniel... that's still impressive.

    a stock GTX SC from the factory with that motor runs 61mph on gps.... you have a HELLUVA lot more boat there and practically pulled the same top speed as a similarly equipped smaller ski

  4. #4
    DAGO RACING CREW 97GPSLEEPER's Avatar
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    I think that is impressive. I believe stock, the SUV ran 50-52? You did a clean job on the install, it looks factory. I would angle the hell out of the ride plate and try to get more hull out of the water.

  5. #5
    My son (mohawk man) jeffsntx's Avatar
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    Quote Originally Posted by ISLANDRACING View Post
    You have to get as much of that big hull out of the water as possible. The SUV basically uses all the same pump components as the XLT. Mods like a 5 degree nozzle, one of our modded rideplates. The ho pump would be the way to go, but i saw in a previous post your looking to retain the old style pump for now.---TRY A NU-JET!!! We built some seriously fast XLT's running the Nujet in the old pump setups-- they work real well with the heavier hulls.

    Daniel, I have a couple of the 67X 5 degree nozzles sitting around if you want to try one.

  6. #6
    Hydrotoys's Avatar
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    Dan,
    Depitch your prop. Your rpms are too low.

    That's actually pretty impressive numbers considering that engine.

    Im in need of some serious pump and hull tweeking advise here. nothing lines up in the back, all the rideplate,shoe,grate,etc all are at different levels, and i know the megascoop is mega scrubbing speed
    What is a "megascoop?"

  7. #7
    Moderator OsideBill's Avatar
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    What was your acceleration like?

    How bad did it cavitate out of the hole?

    was it porpoising?

    what kind of crazy scoop grate?

    what ride plate?

    is the pump shoe sealed?

    Could you get it to hit the rev limiter at all?

    Some detailed pictures of the hull would help grate, shoe, ride plate etc.

    These hulls do not have trim tabs and may require some type of custom tab to extend past the hull. also a custom angled sponson since there are no off the shelf ones you can buy. you are definitly in a new area with this ski I could never get mine over 55 with the stock motor I know that more speed could be had it is jus finding the combination of parts and tweaking

  8. #8
    fabrication guru rapidacceleration's Avatar
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    well heres how it felt.

    from the punch dead stopped
    spun the prop but then it "catches up" and pulls hard. feels to me to not have enough prop on bottom but too much on top. the "mega-grate" that is on it is sucking the back WAY to much down so that things gotta go too. acceleration once you get it moving is GREAT. it outpulled the RXT i was filming from at midrange but leveled out quicklly at 7300RPM with the 7350 peak once. also considering borring the stock nozzle for more volume. I think that may help get this big boat moving easier.. the nozzle masures 87 MM now. how about borring it to 88 or 89MM??????

    and the plate all don't line up under there. there like 4 different plane on ridding on
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  9. #9
    My son (mohawk man) jeffsntx's Avatar
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    In the pic it looks like there is a patch on the hull in front of the shoe on the left side of the ski. If it is a patch it needs to be cleaned up real bad. Then you might try to get everything lined up with some grinding and shimming. It also looks like the shoe is not sealed.

  10. #10
    Hydrotoys's Avatar
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    Yup,
    that patch is going to eat speed.

    See the beaten-on aluminum nose cone on the prop? Get rid of it. Leave it empty.

    The pump shoe itself needs to be sealed to the hull, and it will help with your out of the hole spin.

    That grate is probably your best bet. You could TRY a stock grate, but the big skis have been known to violently turn sideways in just the right conditions. That grate prevents that.

    The rideplate is recessed up higher than the shoe. This is normal. Do not seal it.

    I'm no expert, but your rpms seem low, which would make me think you are over-propped for such a heavy boat.

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