Prop Size for a 87 22 Classic?

[DamnDonzi22]

What is the right prop size for a 87 22 classic with alpha drive? Motor is 454/365 hp. Turns 4700 rpms with a 21 pitch cleaver.Thoughts?

[oledawg]

Good question, my "new" 1988 C22 also has the 454 Mag with Bravo One. It turns a SS 27p, which of course I have no idea what this means, but the boat, as is, just picked up about a week ago from the previous owner, and certainly needing a lot of TLC aesthetically, will only run a little less than 65 mph. I am still figuring out what needs to be done to get it reliable and performing as it should. I know what to do on the TLC. Even dealing with an electrical issue now, one of, maybe even the, main breaker is keeping me from starting the boat or even lifting the outdrive for trailering. Got it on my boat lift, so no issue, but got to figure it out. On the these old boats, no schematics. Anyway, will be interesting to see what the experts come up with on the prop question. Best. :cool!:

[BigGrizzly]

Oled, that is way too much prop for that boat the numbers sound more like a 23/25, unless your drive is way less then 1:50 to 1. Answer to the origional question is a 23 Mirage or turbo1.

[oledawg]

Ah, the description is what I was told, not what I know, so it sounds like I should actually look! Where do you look to determine what prop is? I gather that props are your thing, so should be some good guidance here. Thanks. :cool!:

[MOP]

IMO 4700 with a 21 says it is not putting out the power it should be, you should be able to spin a 23 up close 5000. For starters it is always good to pull the plugs to get an idea of how it is running, if you are not sure about what they should look like post some pictures. If they look Ok then check the timing, base timing is not important "top timing" is. Run the engine up and watch where the timing stops rising, it should be set it at 30-32 degrees. This is best done at the dock, it is not a good idea on the hose you can damage an impeller. Top timing is the most important setting for our marine engines, you will need a timing light with a timing dial or buy a stick degree tape. Make sure it is running right before worrying about props!

[MOP]

Ah, the description is what I was told, not what I know, so it sounds like I should actually look! Where do you look to determine what prop is? I gather that props are your thing, so should be some good guidance here. Thanks. :cool!:

Stock props have the markings under the retaining washer on the props hub, many others are marked on the side between the blades.

[oledawg]

Thanks again, AND another perhaps stupid question: I have seen something that looks like double props, ie one stacked on another. What is this about? :cool!:

[fogducker III]

Thanks again, AND another perhaps stupid question: I have seen something that looks like double props, ie one stacked on another. What is this about? :cool!:


Just an example, "mostly" used on larger boats....

http://www.volvo.com/volvopenta/turkey/en-tr/marine_leisure_engines/drives/xdp_duoprop/xdp+_duoprop.htm

[fogducker III]

There was also the Blackhawk drive by Mercruiser and I believe the Bravo III is a duo prop set up....?

[CaribouLou]

Bravo III is a dual prop yes.

[MOP]

Your drive ratio is 1:43 so you will always be about an inch different from a 1:50 Merc setup.

[CaribouLou]

Your drive ratio is 1:43 so you will always be about an inch different from a 1:50 Merc setup.


What?

[MOP]

What?

Just a tid bit so you know your final drive ratio!

[oledawg]

Actually what my prop is said to be is a Mirage SS 27p, but I will confirm. It is a "big'un" that I do know. Like I said, I will check this week. If it is a 27 what does that mean, top speed, holeshot, more rpm, less rpm? What is the relationship between size and these parameters? :jestera:

[CaribouLou]

Just a tid bit so you know your final drive ratio!

I wasn't talking about my drive, I'm aware of the ratio though. I was just saying that the Bravo 3 drive is a dual prop drive....atleast the B3's that were on the 293 Cobalt down in SD.


But 27p would be top end, but you'd have to have a pretty strong motor to really push that prop.

23 seems to be good for a stock big block.

[oledawg]

Not real sure about the motor either, other than it was described as "454 Magnum with an Edelbrock manifold, 850 Holley doublepumper, 4 bolt main, roller rocker arms" and that is all that I know about it. I haven't had it in a shop yet to really check it out. Not sure how you would know actually. Feels strong, runs good, sounds good, and the speed is decent. Just keep feeding me info and I will eventually figure this puppy out! :cool!:

[CaribouLou]

That motor sounds like it puts out quite a bit of power....Maybe just try a 25p

[DamnDonzi22]

Running a 21p cleaver, rpm's 4800. 21p Mirage Plus, rpm's 4600. 23p Mirage Plus rpm's, 4400. Full trim plus some trailer trim. Speedo jumps around alot. No GPS. Hard to tell on the speed. Felt faster once on plane with the 23. Rough and very windy. The 22c loved it.

[oledawg]

Think that I am just going to leave the Mirage SS 27p on for now, will research some more during the off season. I really don't see much downside. Boat runs 60 - 65 GPS, I am not into holeshots and prefer to build speed rather than slam it up, 4000 - 4200 can't be too bad on the motor/drivetrain, so why spend money to turn more RPM's and maybe a couple of MPH? I guess that I am not a speed geck, although my marina guy here said that although I would get more RPM out of a 23/25 I would likely get less MPH and faster acceleration. Guess those opinions are like AH's, everyone has one! So, if there are good, solid reasons to spend money to change props I am all in, if not I will maintain the status quo.

Best. :wink:

[BigGrizzly]

The 27 M+ is all wrong with the numbers you give. My boat with about 700 hp and a 1:50 drive is low 80s at 5,000, but handling sucked. #365 poinies is not enough to spin that prop. that hp and a 25 pitch gets you about 71 with a 1:5 ratio in real life on a 22 classic.

[oledawg]

OK, so what you recommend bottom line is a Mirage SS 25p? Maximizes speed without causing any weirdness, correct? Just adding to my input and you are considered to be one of the experts.

Best :cool!:

[BigGrizzly]

Actually, that or a Turbo I or TXP. My own experience is on MOST 22 classics the Turbo and TXP work better. Now if a 25 Mplus is handy try it as a base line If you have to pay for it and it is a one way trip I would not. Truth is there are more turbos on 22 on this registry then anything else and there must be a reason for that, not just that I sell them. Only about half come from me.

[Planetwarmer]

I believe that the 1987 Alphas have a 32:1 drive ratio. Running a 21p and 32:1 is like running a 23p 50:1. Most of the stock 22Cs with Bravo drives run a 50:1 and a 23p (on the older boats, that is) and turn similar RPMs as the 32:1/21p.

The tag on your starboard valve cover will tell you the max RPMs for your motor, unless it is not stock.

[CHACHI]

The 27 M+ is all wrong with the numbers you give. My boat with about 700 hp and a 1:50 drive is low 80s at 5,000, but handling sucked. #365 poinies is not enough to spin that prop. that hp and a 25 pitch gets you about 71 with a 1:5 ratio in real life on a 22 classic.Grizz, you are more than close.

My '99 with a 454 (385 hp) turning a 25 pitch Spinelli 4 blade, (I don't know what the prop was that they started with all the stock markings are removed) 1:50 drive will turn 5100 at 73 and change.

Ken

[Planetwarmer]

Grizz, you are more than close.

My '99 with a 454 (385 hp) turning a 25 pitch Spinelli 4 blade, (I don't know what the prop was that they started with all the stock markings are removed) 1:50 drive will turn 5100 at 73 and change.

Ken

Is that all that your engine is putting out, and you are running 73? I have 55 less horsepower and am only running 63-65.

[BigGrizzly]

Thanks ken, you know me, I deal in what I know. I try to give the correct answers to save $$$ and heartache Ken had a alpha drive I believe. but that is only 1 or 2 mph. Planet, there is a majior difference between the 330 and the 385 HP. the 330 is a weak one On the Criterion with many props tried the best I got was 65 mph, mostly about 63 was it. On Tom's Tomahawk, with a 454 mag we got 71 at best day.

[CHACHI]

Thanks ken, you know me, I deal in what I know. I try to give the correct answers to save $$$ and heartache Ken had a alpha drive I believe.

I had an Alpha on my Minx, my 22 is a Bravo with a 1.5:1 ratio.

Ken