Surf & Turf

[Donald Morris]

New Member, New Boat...

1987 Z29 w/454 mag alpha ones. What do you all think she'll do?

MPH?
Max. RPM?
cruise RPM?

I will be taking this boat to altitude (4000') and am trying to size the props.

[boldts]

Mr. Morris,

1st - Welcome to the Registry! :)

On the props and engine RPMs I can't help much since I live in Ohio, but I'd bet you loose anywhere from 4 to 600 rpms meaning a need to drop the prop pitch a couple inches. If you have props for the boat currently, I'd run it with them first and see where everything comes out. Since your purchasing 2 props, I'd want a baseline to work from before making a decision on new props and pitch to run. There are a number of websites that offer a prop calculator. Once you know how many RPMs the boat will turn at 4000 feet, plug the rest of the numbers (prop pitch, outdrive gear ratio, slippage (.10 to .15) into the formula and then start changing the prop pitch to find your best MPH at recommended engine RPMs.

Let me also remind you that just because an engine has a recommended RPM range of 5000 doesn't mean it will be fastest with a prop that puts the engine at that RPM. Then it's prop test time. Most prop sales shops will allow you to try a prop size and if adjustment is needed in pitch allow you to return the props for what you need.

Hope this helps a little. Good luck dialing her in!

[MOP]

Check with you local dealer or possibly the engine manual to see if the engine requires a jetting change and different plugs to suit that altitude.

Phil

[rickrsbro]

25 or 6 to 4.

pull the timing back a tad also. :wrench:

[Donald Morris]

Thanks for the welcome... and the responses!

Boldts- I didn't get any manual with the boat. Is the recommended engine RPM 5000? And how do I find out what my gear ratio is? I have searched the internet and as far as Donzi's are concerened, dis is da place! I think I understand what you are recommending as far as running the engine at WOT. It's not nessessary for top speed, right?

MOP - COOL, I was hoping you would post for me! Already have addressed the jetting and will look further into the plugs.

Ricksbro - Roger on the timing, but, what will that do?

Fellow Donzi Owners/Posters Thanks a bunch... I have always wanted a Donzi since I was 11 years old living in Westport, CT. 32 years later well... I am sure many of you know. Now stuck out here in CA, (which is not so bad) looks like I have little competition (not to many Donzi's) Still I want my Donzi to Rock Lake Tahoe! Looking forward to many more posts and learning alot more about Donzi Boat Ownership...

I am so stoked... thanks again to all! :jestera:

[Fish boy]

Hey Donald, welcome to the registry. Here are a couple of prop calculators that were mentioned above. But it really is best to run it hard and trimmed (possible a little light on fuel) with the props you have, check the rpm, top speed, and then post the results as well as how it ran (blow out, need to get the bow up, etc). You can also plug the info into the prop calculator.

As for the gear ratios, I found this on the net:

Transmission Ratios
Gear Ratio - Alpha Drive (primary/optional/high altitude) 1.47/-/1.62
Gear Ratio - Bravo One (primary/optional/high altitude) 1.5/1.36/1.65
Gear Ratio - Bravo Two (primary/optional/high altitude) 2.0/1.81/2.2
Gear Ratio - Bravo Three (primary/optional/high altitude) 2.0/1.81/2.2

Prop calc 1 (http://www.boatramp.com/prop_applet/PropAnalyzerAppletG.html)

Prop calc 2 (http://hillpropellers.com/propcalc.html)

Prop calc 3 (http://www.rbbi.com/folders/prop/propcalc.htm)

[Donald Morris]

First I gotta say... Love those avitars. You guys are too much, what a crowd. Gimme some time and I'll think of a good one too (and a snazzy name).

I have the Alpha Ones, how can I tell wether its primary or high altitude? If it's primary is it expensive to re-gear it to high altitude?

Thanks for the prop calc's...

[Donzigo]

Welcome Donald,

Thanks Fishboy, for the prop calculators. I did the compute and my prop is experiencing 5% slip with the 33. I'm guessing that's correct; because at 4,400, 1.5 ratio, 23 Mirage, I am getting 60.7 MPH by the GPH and that's exactly what the calculator says, at 5% slip.

Donald, you'll find the ratio under the sticker on the left side of the outdrive, when looking from the back of the boat. My guess is that it came with the 1.3 ration and like many of that era, probably burned up, if ran hard, then a 1.5 was installed. (This happened to my 1987 Alpha). So, the sticker might not be correct.

Cruise is usually in the 3,200 to 3,400 range for the 454. Speed: Depends on so much. It was probably made to do about 55/60 MPH, back when it was built, my guess.

You'll have so much fun working all these things out. three years from now and lots of trials & errors will make you an expert.

[MOP]

Fish boy found some good stuff, on the side of the gear case look at the sticker the gear ratio is on it. Many times you can get what you want with just props, a gear change is not cheap. I hope Dons' Mile High spots your post he is running way up also and may give you an idea as to how many inches to drop the pitch and what needs to be done to the engine. Happy Donzi Daze and don't get a nose bleed way up there!

MOP at Sea Level!

[Donald Morris]

Donzigo - Nice visual, your 33 comands a strong frontal precence. Thanks for the info and I do look forward to the upcoming years of dialing in "the need for speed".

Thanks Phil...

[Cuda]

Richard, that 5% slip is fantastic! You won't get any better than that. Are your props Mirage or Mirage+?

[Donald Morris]

Cuda - What happend to your rear end? I was getting used to the logo...

[Cuda]

Cuda - What happend to your rear end? I was getting used to the logo...


I gave up crossdressing. :jestera:

[Donzigo]

Hard to beleive I have only 5% slip; but, the calculator says it's true.........go figure.

Mirage 23 pitch, not Mirage Plus or anything special, not cupped, etc.

[Cuda]

Richard, don't change a thing, sounds like it's dialed right in. :smile:

[GKricheldorf]

Hi Donald,

Where in Ca are you? I live in San Marcos (30 miles north of San Diego). You are correct about the scarcity of Donzi's out here. Seems like the only people that know them are from back east, but you sure get a lot of people asking about what kind of boat it is when you come rumbling back to the dock.

I'm sure you know, but those 454/Alpha One combo's are kind of a mistake. Be sure not to full throttle out of a hole shot. You may find yourself replacing your out drives. I've been warned by every mechanic and the previous owner.


Glenn

[Cuda]

A marine mechanic here had a 454/alpha combo in a heavy fishboat (26 Pursuit). They used it in fishing tournaments. He said he got 3000 hours out of it. It never did break, but he just had another engine and bravo from a job they did and swapped it out. I think it was due to the fact he probably kept outdrive oil instead of salt water in it. ;)

[Donald Morris]

Glen - thanks for the toughts. I did not know about full throttle hole shots but I did hear a little about the Alpha's being the weakest link. I'm out here in Northern CA. San Francsisco Bay Area.

[Andy McCarty]

not sure if my last post went through. i have a 88z25 454 330hp bravo outdrive. with 19pitch prop. i just got the boat and wouldlike for some assistance figuring out what pitch prop to use. i was running itthis weekend at 4800rpm at about 46mph. but had plenty of throtle left trimmed all the way out. i feel like i am loosing alot running the 19 pitch. i am hoping you all can help me to calculate and get the right prop also. i also posted this under 88z25 questions and someone recomended look at theis thread. Thanks in advance.....:biggrin:

[smokediver]

San Marcos , the Acapulco lounge , they used to have $1.50 Long Island iced teas on thursday nights :beer:

[Donzigo]

Andy, I had that combination and ran a 23" Mirage to get 60MPH. Worked fine for me.

Yes, be gentle with the Alpha/454 combo.

[GKricheldorf]

San Marcos , the Acapulco lounge , they used to have $1.50 Long Island iced teas on thursday nights :beer:


I haven't been there in a few years. Used to go all the time in my early 20's. Restaurant Row has grown quite a bit. There is now a 16 theatre movie complex next door.

[Donald Morris]

Donzigo- What? Is that Big Dady Donzi and Minnie Me Donzi, both yours? Geeze.. some people are just never satisfied. Can't say that I wouldn't want a cruiser and a flyer!

Make me feel better about myself and my first purchased power boat at 43. Tell me the 31' is your Mothers...

Donzinot (Donald)

[Donzigo]

It's actually a Z-33; and, it's my grandmother's........

The Donzi classic 22 belongs to my son.

Richard

[Andy McCarty]

Donzigo that looks like a Z25 next to the big boy. A good friend of mine has a Z33 and they are awsome boats. :boat: :odie: :odie:

[boldts]

Andy & Donald,


Richard (Donzigo) used to own both a Z25 and the Z33. The Z25 was sold to a fellow out West I believe. Richard had gone through the Z25 from top to bottom in a complete restore including the stringers. In other words, Richard knows the Z25 very well! :) BTW, he has also said a number of times how much that Donzi is missed.

His son (DonzigoJr) just picked up a 22 Classic last year and went through a complete engine rebuild for the boat.

Both are very knowledgeable and helpful when asked a question. I look forward to seeing them both at the Donzi Owners Rendezvous 2004 in Sarasota. This is a gathering that everyone in the Donzi family needs to attend. It's done 1st class and has American Marine Holdings Inc. behind it. If you have any chance of saving some time-off from work, save it and attend this gathering.

[Andy McCarty]

Boltds when is the Hometown in Sarasota? I cant bring the Z but might think about me and my wife fly in and visit with all you guys. I have really enjoyed all the help i have gotten and cant wait for the AOTH next year seeing how it is @ my home lake. I am trying to get the trailer in shape to be able to go to a few events. i hope to deffinately attend several next season with the boat.

[boldts]

Andy,

See the Events and Gatherings heading here on the Registry. Donzi Owners Rendezvous 2004 is scheduled for Oct. 1st thru 3rd. Can't make reservations yet, but Mike Miller who used to work at Donzi is getting everything lined up.

[Donald Morris]

Boldts- Richard was kind enough to spend an hour plus with me on the phone this morning. After not too much elctronic therapy, he has gotten me started on the right road at least. The only problem is before I have even drivin this boat he's already got me thinkin about buyin another. Nice guy huh... Richard, I know I have thanked you, but I must again and all the other members of this registry. I am so pleased to have purchased the boat of my youthfull dreams and come to find out the magic and community that goes along with it.

As far as the invite to Sarasota, I'm in. Won't have a boat but I'm sure I'll find a ride or two.:rlol:

[pmreed]

Be sure to come to Sarasota, Donald; there are always more seats than butts :D

Phil