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8318
05-30-2009, 08:09 AM
I am looking for prop information for my 83 18 clasic.
I am having a 500hp+ Dart 400 built for the boat.
All the good stuff is inside the moter to bring it to an easy 500 hp.
I am using an alfa ss drive 1.5.1 and am wondering on what prop to use?
The boat had a 383 350 hp in it before and spun a 23 Laser 2 to just over 70.
Thank you for any help in this.
Dave

BigGrizzly
05-30-2009, 09:14 AM
First I want to see the dyno sheet with the hp and torque and the desk top dyno 2000 doesn't cut it. Your over the limit of the SS by a good bit. I would start with a 28 pitch that way you won't be too small. You must have been really twisting the 383 tight with the laser 23. This is just the beginning, If you don't have full hydraulic steering testing is going to be exciting to say the least:yes: I am going to let everyone argue on the 3 vs 4 blade thing. When you are done with the rest call on the best.

MOP
05-30-2009, 09:21 AM
Did someone say Pooooof!

BigGrizzly
05-30-2009, 09:42 AM
MOP your such a killjoy.:yes: You old fart, don't tell our old guy secrets. Besides it mite not happen:nilly:

The Hedgehog
05-30-2009, 09:48 AM
Wow. That should be fast. I would start shopping for a Bravo and a shorty

BUIZILLA
05-30-2009, 10:38 AM
nice package....

IMO you would be better off upgrading the drive NOW rather than waste an SS that you may not be able to fix and therefore has no resale value to put towards a better setup after the fact... just my .03

The Hedgehog
05-30-2009, 12:02 PM
nice package....

IMO you would be better off upgrading the drive NOW rather than waste an SS that you may not be able to fix and therefore has no resale value to put towards a better setup after the fact... just my .03

Good thought. It is easy to find a taker for the alpha ss

8318
05-30-2009, 01:54 PM
I know that the ss might come apart with this set up.
I do not run the boat hard off the line I do not go crazy jumping every wave I can find.
I run the boat in a big calm lake.
I am planing on changing the drive next winter.
The boat has Power stering but not external power stering.
The motor is being built by a great shop everything from 1.1 miil Ferrari engines to drag motors. Great shop and they have built 4 motors for me over the years.
The lap top dyno thing as you stated is to be taken for what it is, an estamate. It gives the build @ 568 hp so I toned it down to 500.
We will see.
I know this much I will be spending alot of time at the airport buying 101 low lead.
Grizzly it looks like you work on setting up props how do I contact you or your place of bussniss.
Thank you all for your feedback.
Dave

olredalert
05-30-2009, 06:19 PM
-------The boat you are describing sounds like a twin to a buddy of mines 18 near here in Algonac, SS and all. I dont know what prop he is running but he has had the boat together for at least 5/6 years and finally hurt the motor a bit late last season. The drive has never hicupped once to my knowledge. I will say that I dont know if he did anything special to it, but I think he would have mentioned it if he had. He is not a big wake-jumper either.........Bill S

BigGrizzly
05-31-2009, 09:06 AM
Bill I have heard of this on a few occasions, very few.

olredalert
05-31-2009, 09:21 AM
------Grizz,,,Part of his DONZIs longevity might be that he is a GM engineer and very mechanicly oriented. Does almost all his own work. He also isnt a big wake jumper. Just likes to go fast!!! He is also just finishing up a Jersey skiff that ought to give most of his passengers a brown stripe in their shorts. He actually told me that due to GMs situation and everyones tenuous employment there, that he might entertain the thought of selling the DONZI after freshening the pill. Its a north of 80mph boat all day long.........Bill S

BigGrizzly
05-31-2009, 09:29 AM
Actually I figured something like this which is what each of the long lived SS have in common. the guy here has his on a 24 python, lot of them on this lake:yes:, home court. Is an engine guy and is really a maintenance freak, as was the other one, he is a Merc instructor. Can you say careful.

Choprpilot
05-31-2009, 04:13 PM
I'm also running an SS drive on my 18 Classic LE with a 468 BBC (579hp) in front swinging a 26p round eared clever. I have only had it to 5400rpm because I've heard that the SS drives to not like rpm over 5500. So far so good.

Just Say N20
05-31-2009, 04:19 PM
What is a round ear clever?

fogducker III
05-31-2009, 09:09 PM
I'm also running an SS drive on my 18 Classic LE with a 468 BBC (579hp) in front swinging a 26p round eared clever. I have only had it to 5400rpm because I've heard that the SS drives to not like rpm over 5500. So far so good.

Just out of curiousity, what top GPS speed have you hit?? I take it you have 1:50 gears..?

PlumCrazy
05-31-2009, 09:54 PM
My last boat was a '88 Baja Sunsport 196 which is not too much bigger than your Donzi. The engine was a 500HP 357 SBC with a 125HP shot of nitrous. It too had a 1.5:1 Alpha SS. This setup had over 200 hours on it with lots of time running 6000 RPM naturally and 6500 RPM on nitrous. Speeds were 79 and 84 respectively. I had my mechanic go through the drive and it was in perfect condition. Take it easy getting on plane and also letting off the throttle and this drive will perform well.

The best prop I ever found for it was a standard Mirage 23P. But, I also ran a 26P Spinelli cleaver. The top speeds were the same, but the Mirage was better all around.

Some pics...

http://img.photobucket.com/albums/v215/dpluhm/Baja/baja2.jpg
http://img.photobucket.com/albums/v215/dpluhm/Baja/baja1-1.jpg

younger
06-01-2009, 09:01 PM
Just for comparison I just installed a full roller Bill Mitchell race shop 415sbc in my 16. I run 1.32 gears in an alpha genII. I over drive the top case with the lower 1.32 ratio to run smaller prop pitch. So far the engine has gobbled up one drive this season. but it was my fault. The drive had 5 years of hard running behind a 400 hp 350 sbc. After inspection my upper bearings were shot and i was getting gear bind. I rebuilt the drive and have a couple hours of break-in time running a 19 laser II. This combo has spun to 5800 very easly. As we all know to make the alpha live it needs to stay cool, and be babied when comming on plane and in the rough stuff. One little trick to keep the drive cool is to take the top cap off the upper housing of the drive, pull the rubber plug out of the water cavity at the rear part of the housing. Next in the top of the cap drill and tap a hole with an 1/8" npt tipping slightly forward. Put a 90 deree fitting in so that it points forward at the top center of the cap. As a resault when the engine is running water at all speeds is running across the top of your drive cooling it. As well with the rubber bung out it there is more water volume to the inside upper housing. I will see if I can snap some picks and post. As for more prop for me I have run a 15.25"x22 four blade mach cleaver with good rreturn but have not stepped up for a full throttle blast need a passneger to hold the interior in.