New Donzi owner in Norway, propeller question

[Cummins_12v]

Hello, im a new Donzi 22 classic owner. I have a question about the propeller. In norway i propably have 1/5 22c so its no experts here. Its a 22c from 1992, bravo 1, overhauled chevy 350 with new alu heads camshaft etc, around 400hp. I now got a 4 blade offshore 23p, i can do 62,5 mph at 4800-4900 rpm. Wondering about a 25p 3 blade to get some extra top end speed, any opinions? Also woundering abot size, 14 1/4 or 14 3/4? its a 1" shaft on the bravo one?

[Cummins_12v]

Or what about cleaver props? How do they work?

[Carl C]

Cool to see someone from Norway posting here. I've always been fascinated by your country. The prop gurus will respond soon I expect.

[MOP]

I have a SB 22, it is a 383 with about 375HP I spin a 4B 23 on a good day I turn 65.5@5000. IMO your speed is held back somewhat buy the a low X dimension, most later boats were setup A 15-1/2". I have an 86 that was a Tempest setup with an X of almost 17", props will only get you so far. A shortie may be in your future!

[BUIZILLA]

leave it alone...

[Cummins_12v]

So you dont think i can get it to the upper 60's with a 25p 3 blade?

[Cummins_12v]

Cool to see someone from Norway posting here. I've always been fascinated by your country. The prop gurus will respond soon I expect.

Its a nice country, but not so many experts on motorized things other than small jap cars and yamaha 50hp outboard :)

[axelkloehn]

low 60s sounds pretty low for 400hp in a 22c, I would give a 25p 3-blade a try. Some here have good experience with the Mirages. Also diameter of 14ish sounds too small. I am running my GT21 around 60mph with stock 350 sbc, Bravo1 and a Mirage 23p blade (14 3/4) at about 4600 rpm, but I have a raised X-dim (almost 1 inch up). May be the 4blade has a lot of slip...

[glashole]

listen to buizilla

[Cummins_12v]

low 60s sounds pretty low for 400hp in a 22c, I would give a 25p 3-blade a try. Some here have good experience with the Mirages. Also diameter of 14ish sounds too small. I am running my GT21 around 60mph with stock 350 sbc, Bravo1 and a Mirage 23p blade (14 3/4) at about 4600 rpm, but I have a raised X-dim (almost 1 inch up). May be the 4blade has a lot of slip...


Which of these props should i buy:
13 x25 5 High five kleever Rep. 4 3/8
13 1/2x25 4 Renegade 175738 4
14 3/4x25 3 Tempest 48 825866A40 4 3/8
14 1/4x25 3 Rapture 33082 4 3/8
14 1/2x25 3 Turbo 4 3/8
14 1/4x26 3 Turbo 4 3/8

Hope that someone knows, i get those used props for 200-250 Usd

[axelkloehn]

...the one with the best result! Here comes the testing time! No one will be able to tell which one will give the best result without testing it on your setup.

[Cummins_12v]

Now the boat are going to be polished, and changed all fluids before øøhitting the water again in the summer :) again i will ask the prop question, i cant just try and dail, props are 500 usd. Someone over there willing to sell and ship a prop to Norway? 25p mirage plus?

A guy from the other end of the country have some props, can any of these be recomended?



3500 15 1/8x28 3 Solas 110mm

2000 14 3/8x27 3 Mirage Fast nav 48 19836 110mm

3500 14 1/4x26 3 Michigan Wheel 110mm

2500 14 1/4x26 3 Turbo 110mm

2500 14 x26 3 No Name 110mm

2500 14 1/2x25 3 Turbo 110mm

2500 13 1/4x25 3 Shooter 100mm

2500 14 1/2x25 3 Turbo 110mm

2500 13 x25 5 High five kleever 110mm

2500 13 1/2x25 4 Renegade 175738 100mm

2500 14 1/4x25 3 Rapture 33082 110mm

2500 14? X25 3 quicksilver laser 2

3500 16 x24,5 3 Solas 2 stk NY 110mm

2500 14 1/4x24 3 No Name SZK 110mm

2500 14 1/4x24 3 Turbo II 110mm

2500 13 3/4x24 4 Trophy plus 48 825 940 UH 100mm

2500 14 1/2x24 3 Turbo II 110mm

2500 14 1/4x24 3 Turbo 110mm

2500 14 1/2x24 3 Raker 394755 110mm

2500 13 1/2x23 3 Quicksilver 48 16320 110mm

2500 14 1/4x23 3 Quicksilver CLEEVER 110mm

3500 16 x23 3 Solas NY 110mm

3500 14 1/4x23 3 Ballistic 110mm

2500 13 3/4x23 3 Laser II 110mm

2500 14 5/8x23 3 Mirage plus 48 13704A40 110mm

3500 13 1/2x23 3 Vengeance 48 16320 NY 110mm

2500 15 x23 3 No name 110mm

[Pismo]

Trim it more, much more..

[Cummins_12v]

Cant trim more, 62mph are top speed at 5200rpm, more trim, just spinning and loose speed. So i need more pitch :)

[joseph m. hahnl]

That's 18% slip are you running an aluminum prop? Your four blade should carry the hull better and get less slip then a 3 blade. Who makes the prop you Have?what is the drive ratio? I assumed it was 1:1.5.

23P 5200 RPM with a 1:1.5 @ max> .10% slip would be 68MPH.


Every inch of pitch is 150 to 200 RPM

In theory by going to a 25P you'll loose 400Rpm

25p 4800 RPM with a 1:1.5 @ max>.10% would be 68MPH

Every inch in Diameter is 500 RPM.

so preformance wise the prop you have is slipping excessively for one reason or another. Most marine V8's are governed as not to exceed the torque curve of the cam shaft. That is usally the max target Rpm which is governed by the pitch.

[MOP]

IMO the last thing you want to do is to load a small block down with more pitch, the pitch you are running is spot on. I am running a very similar setup. I am getting 65.5@ 5000 with a 4 blade 23" Turbo Ultima, I get almost the same results with a Turbo 2+2 23 4 blade. I think you have a funky prop!!!

Phil

[MOP]

Added note what is your top timing set at? Should be 30-32 degrees, you may just be low on your timing. Make sure you engine is running its best before you get carries away with the $$$$!!!

[Cummins_12v]

Its a mercury offshore series prop, it looks like brand new. I dont know about the timing, but the engine is rebuilt 2 yr ago. With new aluheads, camshaft,intake, carburator. The enginr builder assume it puts out about 400hp now, then i think the 25p would be better ?

[Cummins_12v]

Is this prop worth a try? I can propably get it cheap :
2500 14 1/2x25 3 Turbo 110mm

Or the rapture in same dimensions?

[mattyboy]

The 22 can't be lumped all together over the years they changed comparing an 87 that has a raised X and is probably 500 lbs lighter to a 92 probably one of the last CC made 22 or maybe the first AMH boats That has a different bottom, tips the scales at 3400 lbs or more with a heavy layup schedule isn't really a fair comparison.


you need to find out your drive ratio

find the right prop that will get you to 5000 rpm at 10 % slip

a sbc is at a weight disadvantage in a heavy 22 not enough weight in the back end more weight aft less wetted surface.

I would say your shy of the 400 hp mark

[Cummins_12v]

How do i find out the ratio? Was'nt the same ratio on all bravo 1? But if i should try a prop from the list i posted, give the 25p 3 blade 14.5inch turbo a try?

[MOP]

[ QUOTE= The 22 can't be lumped all together over the years they changed comparing an 87 that has a raised X and is probably 500 lbs lighter to a 92 probably one of the last CC made 22 or maybe the first AMH boats That has a different bottom, tips the scales at 3400 lbs or more with a heavy layup schedule isn't really a fair comparison.


you need to find out your drive ratio

find the right prop that will get you to 5000 rpm at 10 % slip

a sbc is at a weight disadvantage in a heavy 22 not enough weight in the back end more weight aft less wetted surface.

I would say your shy of the 400 hp mark

Please explain!! No matter what hull a SB is in it should not be over loaded, going from a 23" to a 25 will not make it faster it will slow it..

If we are talking 22 weight mine is a fair bit heavier in the stern as I followed Geo's lead on setting up my hull moving as much heavy stuff aft, yes I do have a high X which does help my overall performance.

[mattyboy]

Phil

sorry I thought my response to cummins was pretty well explained.

your setup is not that similar to Cummins


your 87 has weight shifted aft, a raised X , a different chine and a lighter layup than Cummins 92 some of these are better for performance with a small block.

My point to Cummins was he was going to have to try props with his setup and try to get to 5000 rpm with 10% slip that would be a goal to aim for.

I used the term heavy 22 for the 92 which shows a gross weight of 3400 lbs the 87 info I have shows the 22 at a gross weight of 2900lbs that's 500 lbs think that might have some effect on performance between the two??? My point again a small block in a 3400lb 22 with no weight shifted aft will run flatter and with more wetted surface which means slower ( i was not that clear on that in my post and typed the wrong thing). a 92 is defintely a chris craft donzi and from what I have seen of them they are laid up very solid. everyone i know with approx 400 hp in a small block is turning at least a 24 if not 26 pitch on 1.6 gears. won't a late model 415 hp 502 22 C run just about to 70 mph?

I am not a bravo guy how can Cummins check his ratio on the bravo 1 isn't it stamped somewhere

his numbers run close to 10% slip and 1.5 gears right now if he can turn it to 5000 with that prop ( labbed) or get a 24 with 10 % to 4800 he should see a mph or 2 and be at 65 ish

[RickSE]

I think the drive ratio is normally on the port side drive sticker. If not check the other side, assuming the gears have not been changed and the sticker is there. :)

[Jraysray]

To check the gear ratio of the outdrive with the outdrive still on the boat, (with the engine off ) put the drive in forward gear and turn the front of the engine over in a clockwise rotation with a socket and a breaker bar at least 1/4 of a turn to take the slop out. Now put a mark on the engine front pulley and put a mark on the prop. Have someone outside of the boat watch the mark on the prop and turn the engine over by hand until the prop rotates 1 full turn. If the engine had to be rotated exactly 1 1/2 turns to make the prop go 1 full turn, you have a 1.50 ratio which is what you want for a V-8. Other ratios could be 1.65r for some small V-8's and in-line 6 cylinders, 1.84r for V-6 engines and 1.98r for 4 cylinder engines. ( 2nd example : if you had to rotate the engine almost 2 full turns before the prop rotated 1, you have a 1.98 ratio. )
If the drive is off the boat you can do the same as above by turning the u-joints in a clockwise direction while watching the prop.

Note ! If you turn the u-joints in a counter-clockwise direction, you may harm the water pump impeller