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Thread: Help from the experts, or the one's runnin them

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    Help from the experts, or the one's runnin them

    Fellas new here, looking for some knowledge from those who know Props, and step hulls. I am going to add a link to Q&A Posted on OSO. I could really use some conformation or other advice. Appreciate all the help.

    2000 ZX with the 377's. I have a set of 3bl 25p lab mirage boat runs 72 gps 5000 rpm.
    Also have a set of 4bl 26p lab Bravo I 74 gps 5000 rpm.

    What am I doing wrong? Thought this should be an 82 mph boat with the twin step hull? Fuel levels were approx half. 1-4 persons did not matter.

    2nd question. I have been getting a lot of cavitation when getting to plane. I have backed up on the K planes and has since helped. Thanks for any and all help.


    http://www.offshoreonly.com/forums/s...d.php?t=194036

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    are you using non-ethanol, premium fuel?
    Charter Member - WAFNC, SBBR, KWOSG
    1955 Perfect Mate
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    1996 16-OB, 150 TRP Yamaha
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    Let me say this first. That boat won't run 82 with stock Scorpion power And I don't care if Don himself says it will, It is too big!!! I personally think if you have to run a labbed prop to get that extra 1 to 3 mph your wasting money. I believe Trueser Tried some other props at Cumberland that handled better. Since I sell and test props as most know, I can tell you this. You need to try other props. Every labbing guy will tell you his are the best. I have an 86 mph 22 and can say that the only labbed props I have on my boat were labbed Merc racing and two Throttle up props( not their CNC ) and my stock out of the box Precision props were at least 2 MPH faster. I don't labb props and won't, It isn't worth it to me. Ask Trueser for his opinion, He isn't capable of lying about his boat. He likes me and will tell me to stick it if he doesn't believe me. One thing there is more to a boat then just speed, It id called Handling.
    Randy owner of Donzis since 1966
    High Performance props 3, 4, and 5 blade. Turbo and Stainless Steel props. Props for old Volvo drives.
    The reason congressmen try so hard to get re-elected is that they would hate to have to make a living under the laws they've passed.

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    Big Grizz nailed it.

    These boats are all about handling.

    I would take a perfect handling 65 mph boat over a 70 mph skittish boat any day.

  5. #5
    mrfixxall Guest

    mrfixxall

    Quote Originally Posted by IUHalls View Post
    Fellas new here, looking for some knowledge from those who know Props, and step hulls. I am going to add a link to Q&A Posted on OSO. I could really use some conformation or other advice. Appreciate all the help.

    2000 ZX with the 377's. I have a set of 3bl 25p lab mirage boat runs 72 gps 5000 rpm.
    Also have a set of 4bl 26p lab Bravo I 74 gps 5000 rpm.

    What am I doing wrong? Thought this should be an 82 mph boat with the twin step hull? Fuel levels were approx half. 1-4 persons did not matter.

    2nd question. I have been getting a lot of cavitation when getting to plane. I have backed up on the K planes and has since helped. Thanks for any and all help.


    http://www.offshoreonly.com/forums/s...d.php?t=194036
    which way are your props spinning? in or out?

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    Your numbers are correct for those pitches based on 10% slip. You might be able to get 1 or 2 MPH more out of a different set of props and some more seat time but the speeds you are seeing are consistent with the pitch and props you are running.

    I don't know what the rev limiter is on the 377's but I suspect they are right around 5000. It's possible you are hitting the limiter and have some more speed with some bigger props, especially since both sets of props, a 3 blade 25P and a 4 blade 26P both turn 5000 rpm. If you have Faria gauges it's entirely possible the tach is as much as 400 RPM off on the high side.

    To do 82 mph you will need to be able to spin a 29P or 30P prop to the indicated 5000 RPM's assuming you have the 1.5:1 ratio drive (which it looks like from your slip numbers).

    Try some bigger props.
    Cogito Ergo Zoom!
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    I talked to Trueuser. He said with some seat time he was able to get high 70's so far. Maybe he will chime in.

    Mr. X also knows this boat well. I think he broke the 80 mark in his. I seem to remember he did the SM exhaust on his scorps.
    2001 35 Fountain Lightning w500 EFI's
    1973 X-18 - Merc 383 Magnum
    1974 Chris Craft Roamer with 1271 TI's

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    If it helps the way you feel about the boat you are not alone in your problem with the scorpian not living up to the numbers that Donzi published to market the boat, not surprising considering the boating industry inflates the numbers to sell boats or best the other manufacturer. I have only read about one scorpion running 80 plus on stock power, It was Mr X and his with some exhaust upgrades. As for yours.....well it is a bit slow for a scorpion but in the range to be considered normal....Best you will see is high 70's under ideal conditions. Hate to say it but thats the way it is. You may be able to pick up a bit with some better props but ther is no magic bullet that will give you 8-10 mph to make it to 82 with the current set up and power.
    Now if you want to get srious about it I can point you in the direction of a guy with a pair of procharged small blocks and a bunch of other things, extension boxes and big tabs that runs to 95 with authority and will peel your eyebrows back....all in a 2000 28 ZX, boat hails out of New Orleans.
    Tex
    97 27 zx twin step yep it is the slow boat
    500 EFI .........................with a little Boost and
    a little more boost
    48' Pacemaker Tournament Sportfish twin Detroits

    Yeah... I was.... Kind of a Big Deal.....

    Tex

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    Quote Originally Posted by The Hedgehog View Post
    I talked to Trueuser. He said with some seat time he was able to get high 70's so far. Maybe he will chime in.
    Mr. X also knows this boat well. I think he broke the 80 mark in his. I seem to remember he did the SM exhaust on his scorps.
    What happened with his motors?
    97 27 zx twin step yep it is the slow boat
    500 EFI .........................with a little Boost and
    a little more boost
    48' Pacemaker Tournament Sportfish twin Detroits

    Yeah... I was.... Kind of a Big Deal.....

    Tex

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    Quote Originally Posted by mrfixxall View Post
    which way are your props spinning? in or out?

    Inward... To answer a few other questions it handles really well, I was dealing with a little chime walk at the higher speeds, but I got that worked out and as for handling the waves I was out in 5-7's (not Swells) and was running 65. I am interested in any small tweaks you are using. All Freshwater it might be 380hrs on motors. Thanks for the help.

  11. #11
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    Wow I missed this one.

    So far I have hit 79.5 on GPS. One of these days when I don’t have my wife on board I will break the 80 MPH. The rev limiters are set @ 5200-5250. I'm running the 25 mirage plus. Ted’s old boat that is owned by my friend hit 82-84 on GPS. The boat really loves trim above 7 on the indicator. But it also loves to chine walk. I have a pair of 26 Plus but have not tried them yet. The other problem I hate is getting on plane in ruff water. The props blow out way too easy. I just hit 300 hours and they are still running strong. Griz hit the nail on the head. I would rather have the handling than the speed. The 4 blades I tried got on plane in a heart beat. I could stay on plane @ 1500 RPM. But my top speed was only 71mph. I can always throw the three blades on too whoop Roadtrip. I would also like to swap the props around and see the difference in speed, handling and getting on plane in choppy water.

    The other thing that has limited my speed is my busted up hand. It's finally getting to a point where I can trust it to hold the steering wheel.

    I destroyed a pair of Checkmate's with big block twins. After 10 miles of running we finally stopped and I had to lift my hatch to show that I only had small block Scorpion stock motors. And one of the guys was really pissed that he burned up all his fuel.

    Go easy on the Scorpion comments.

    PM me and we can talk. I have a few questions on Bravo 1's

    Where and when did you get this?
    2000 28ZX Scorpion SOLD
    1979 Criterion
    1986 Z29

    RED/WHITE
    TWIN SBC 330HP
    ALPHA 1'S
    Mcleod design Interior

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    That story about the Checkmate rocks. Nice job.
    2001 35 Fountain Lightning w500 EFI's
    1973 X-18 - Merc 383 Magnum
    1974 Chris Craft Roamer with 1271 TI's

  13. #13
    mrfixxall Guest

    mrfixxall

    Quote Originally Posted by IUHalls View Post
    Inward... To answer a few other questions it handles really well, I was dealing with a little chime walk at the higher speeds, but I got that worked out and as for handling the waves I was out in 5-7's (not Swells) and was running 65. I am interested in any small tweaks you are using. All Freshwater it might be 380hrs on motors. Thanks for the help.

    Another question! sre you sure you have scorpionn motors? are they blue or black? your props are turning inward thats the fast and uncontrolable set up for twins and thats probably why your chine walking and have propeller blow out (truesdale)

    Mirage + is the prop to run on that boat(scorpions) they have a little bigger blade to hold the water..

  14. #14
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    [QUOTE=mrfixxall;465689]Another question! sre you sure you have scorpionn motors? are they blue or black? your props are turning inward thats the fast and uncontrolable set up for twins and thats probably why your chine walking and have propeller blow out (truesdale)
    Mirage + is the prop to run on that boat(scorpions) they have a little bigger blade to hold the water..[/QUOTE

    2000 28ZX 377 most likely it is a Scorpion. I am running Mirage 25 PLUS!


    IUHalls Do you have any pictures?
    2000 28ZX Scorpion SOLD
    1979 Criterion
    1986 Z29

    RED/WHITE
    TWIN SBC 330HP
    ALPHA 1'S
    Mcleod design Interior

  15. #15
    mrfixxall Guest

    mrfixxall

    [QUOTE=Trueser;465696]
    Quote Originally Posted by mrfixxall View Post
    Another question! sre you sure you have scorpionn motors? are they blue or black? your props are turning inward thats the fast and uncontrolable set up for twins and thats probably why your chine walking and have propeller blow out (truesdale)
    Mirage + is the prop to run on that boat(scorpions) they have a little bigger blade to hold the water..[/QUOTE
    2000 28ZX 377 most likely it is a Scorpion. I am running Mirage 25 PLUS!
    IUHalls Do you have any pictures?

    I was looking at 28' 2000 zx with twins and the guy stated it had scorpions in it but when he opened the hatch i say twin 350's black mpi motors..mabe he didnt know what he bought and was led to believe he had scorpions in it..
    http://www.boats.com/listing/boat_de...6Ntk%3dboatsEN

    IUHalls are you running a mirage prop as stated or the mirage plus? which is a little bigger prop..

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