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avanti
03-26-2001, 12:59 PM
I am running a 2000 Donzi 18 Classic with a 350Mag and need some help with the prop. When running wide open and trimmed out, I am only getting 4500RPM and 65MPH. I have an Alpha drive with a 25inch pitch Mirage. We were full of fuel and 2 on board. Should I go to a 23inch Mirage or maybe a different type of prop? Thanks for any help you can give me.

Forrest
03-26-2001, 03:48 PM
What is the recommended RPM range for your motor?

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Forrest

Formula Jr
03-26-2001, 06:06 PM
350 Mag is 4400-4800.

Bryan Tuvell
03-26-2001, 06:56 PM
Same set up as mine, 350 MAG MPI, mine is 4800-5000 normal WOT RPM according to the Merc Manual, (and the fire arrestor sticker) book also says rev limiter is at 5100RPM.
I went through several props, I now have a 4 blade stainless Merc Bravo I 24. I hit 5200 RPM on good days solid which has been my best performance late last year alone, 69/70 MPH on GPS. We went this past Saturday and I got WOT, 4800RPM and 65.3 top speed on GPS in some nice chop and winds, Small craft advisory for the bay!

Funny this topic now, it was discussed at length today with a prop guy I know, he heard all my stories just today and said Mirage 3 blade 24 is probably my best bet for my set up!

I guess it is a preference deal, we all want that last MPH or two, especially with the trio I run with who are all BB engines and 7 or 8 MPH faster than me.

I was told my 22ZX comes with the Bravo 24 standard now, which means the factory got it's best results from it over others, or at least one would think so.
Our prop shops Lab them for roughly $125, which is my plan, allot of expense for 1 to 2 MPH, but oh well.

STINGRAY had his done last week, if nothing else Lab finish sure does make them look pretty!

Hope this helps, Bryan

BigGrizzly
03-26-2001, 07:24 PM
Bryan, the Marage Plus only comes in odd numbers-21-23-25->etc. unless you have a shop repitch it is a 23 or 25. no even numhers.

Randy

Bryan Tuvell
03-26-2001, 08:43 PM
Your right, my mistake, I meant 23, one that was tried on my rig in the start was a 21, Gloucester Marine (Donzi Dealer) said the boat was delivered with the wrong prop, and the factory ended up sending us 2 more props and that is where the novice experimenting came in for me, at that time we were stuck at less than optimum performance for the boat.

Still learning, I just removed my foot from my mouth..... So, I was told today with a 4 blade you gain top end by down pitching or raising on a 3 blade based on drag and other factors.

Is this true? I hate to get my education here but the resources are super.

Thanks Big Griz. Bryan

Tom on Lanier
03-26-2001, 09:04 PM
Bryan - what is the name of the prop shop that will "lab finish" for $125. Do you know what they do in that process? I've heard prices more like $300!! Thanks.

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Tom
"Tomahawk"

avanti
03-27-2001, 07:16 AM
I believe the recomended top RPM is 5200. So do you guys think I should go to a 23 Mirage 3 blade? I think the factory over pitched the prop to protect the engine from amatuer operators. Thank you for any help or advice you can provide.

Bryan Tuvell
03-27-2001, 10:00 AM
Tom, here is the info I got from STINGRAY. Hope it helps.

Murphy's Prop Shop, 3349 Azalea Garden Road (757-853-4731). I'll be stopping in this afternoon to drop off my prop for re-pitching down to a 24P from 26P. Price for "blueprinting" was $125. He's gonna give me the re-pitch for $50. He also has various prop stuff for sale and some cool T-shirts if you go in there. Also deals in used reconditioned props as well....

Bryan

Forrest
03-27-2001, 11:23 AM
Though Murphy can surly do a re-pitch, I don't think that I would go an entire prop size (2") down. Too much bending required. Instead, think about selling the prop that you have and buying another with the pitch you need. Murphy has been in business in Norfolk for a very long time and do good work in general, but they aren't know as performance prop shop.

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Forrest

Bryan Tuvell
03-27-2001, 05:26 PM
FORREST, I am not doing anything with my prop, that was my buddies post to me, I am hanging with the Merc Bravo I 24P.
I may try the Mirage since we have one at my other bud's etc...

So when you coming to call on us? I will stock up on oysters and beer!

Bryan

roadtrip
03-27-2001, 05:39 PM
Hey Bryan,
My 22 Classic came with the 25 pitch Mirage plus. I want more top end. Standard trade journals say three blade for flat bottoms to lift the bow and four blades for step bottoms to lift the transom. Hydromotive four blades tend to give more transom lift than Bravo 1 four blades. Hence the reason you have found the right prop, a good compromise.
Now on the Classic, it would make sense to try a smaller 23 mirage plus for speed. A 26 inch bravo would probably scrub speed, but I bet that 24 inch bravo would be an interesting combo. One less inch of pitch, more bite, and maybe a little more speed. Now how do I go about talking you into allowing me to try it at Cumberland? Steaks, cocktails, stogies? Name your poison, Todd

Bryan Tuvell
03-27-2001, 07:54 PM
ROADTRIP. I will add, my bow pops as high as she goes when I nail it from a dead start, but I plane in what I would say is less than 3 seconds with trim tabs up. Number wise according to what I have read that is average, and I am not a built ski boat so who cares! http://www.donzi.net/ubb/wink.gif But we do ski!

I think I have the right set up with the Merc 4 blade Bravo I to be honest, but a 23 3 blade Mirage might be interesting, will I try it? Probably, but only while I get my Bravo I lab finished, as listed above.

I look forward to meeting you in KY... MY POISON, anything legal with smoke coming out of the end, a Cuban would be nice, as far as a beverage, solid black coffee until party time Then BBBUUUDDDWWWWWWWWISERRRRRRRR! Born on dating ya know!!!!!!

Bryan
PS Did that 22ZX in NM sell yet?

Bryan Tuvell
03-27-2001, 07:58 PM
ROADTRIP, also, the helm is yours for a trial run as long as we don't turn real sharp and spin out!!!!!! Be my pleasure...
Bryan