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Thread: New donzi owner prop question

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    New donzi owner prop question

    Hello everyone, I just recently purchaced my first Donzi, a 93 22c with a supercharged 454. The boat runs great I am just new to prop pitch size ect and had a few questions. The boat came with a stiletto 20323 23p prop. the boat has a OMC king cobra outdrive. Right now I am hitting around 70 mph at around 5500 rpm. Is this too small of a prop for this boat? I'm sure I could get 5-10 more MPH with more experiance with trim and tabs.
    Thanks in advance for the help .

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    the OMC KC has a gear ratio of 1.43 to 1. At 5500 RPM and assuming a 10% slip (may be a high assumption) you should see 75+. If slip is lower, then you should be closer to 80. Do you have a guess at actual horse power?

    If the engine is tuned properly, then you need to trim it up more. And yes, you do need more pitch. I would think max RPMs should be in the 5200 to 5300 range once propped correctly.
    RedDog

    President - West Vestal Donzi Owner's Group
    Knoxville, TN

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    what super do you have. a stock 454 runs that size prop.
    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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    PS - Catch 22s Procharged 454 with a Bravo I (and shorty drive) runs low 90s
    RedDog

    President - West Vestal Donzi Owner's Group
    Knoxville, TN

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    The SC is a B&M. I am real new to prop pitches but I felt like the rpms should be lower. previous owner guesstimaded power to be around 500 or so. The boat runs great just seems to spin a little high. what would be the optimum rpm at WOT?

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    Catch22 has a labbed 31 hydromotive and a throttle up CNC 30. I am procharged with OXP28, and a TXP 29/ or #) depending on the day. Speed is not an issue.to be discussed.
    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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    Quote Originally Posted by BigGrizzly View Post
    Catch22 has a labbed 31 hydromotive and a throttle up CNC 30. I am procharged with OXP28, and a TXP 29/ or #) depending on the day. Speed is not an issue.to be discussed.
    Ok do you think I should be running one of those? Those numbers are the pitch I assume?

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    Truth is you have a pretty weak blower, Catch has a shorty and I have over 700 hp. in your case i would go with a 27 TXP. which B&M do you have. Of course this is if you have given me the correct information. you see I sell props and own one of the22 foot Donzi and work with engines.
    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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    Quote Originally Posted by BigGrizzly View Post
    Truth is you have a pretty weak blower, Catch has a shorty and I have over 700 hp. in your case i would go with a 27 TXP. which B&M do you have. Of course this is if you have given me the correct information. you see I sell props and own one of the22 foot Donzi and work with engines.
    I am not sure which B&M it is to be honest. I know it is making low boost like 5 psi. I would imagine there would be a substantial differance from the 23 to the 27? Im not looking to do 90+ I want to be able to do 60-70 at a lower RPM. Do you have a website or more info on that prop?
    Thanks

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    I believe you have the 144 blower. Do not worry that combination will never hit 90.I have given some though to this. that drive and ratio. a 26 or 27 will put you at about 78 at 5200. the engine may or may not turn a 27.
    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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    Quote Originally Posted by BigGrizzly View Post
    I believe you have the 144 blower. Do not worry that combination will never hit 90.I have given some though to this. that drive and ratio. a 26 or 27 will put you at about 78 at 5200. the engine may or may not turn a 27.

    That would be great, Thats exactly what I am looking for. It has imco powerflow manifolds and risers, roller cam, holley 850, and other things I am forgetting, hopefully it would be able to spin a 27. would you recommend a 3 or 4 blade?

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    I sell props and am a Turbo distributor. i would recomend a 3 blade unless the boat is hard to handle then i have another option
    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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    Quote Originally Posted by BigGrizzly View Post
    I sell props and am a Turbo distributor. i would recomend a 3 blade unless the boat is hard to handle then i have another option
    What exactly do you mean by hard to handle? sorry for all the questions, I appreciate your input

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    Sometimes a 22 can be difficult to handle at full speed.
    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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    No I don't have that problem. Could you PM me a price for the txp 27p ?

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