www.iFourWinns.com

I do have questions with anyone elso who has the same setup I'm using. 377 (6.2L) or 350 Mag, B1. This boat came from the dealer with the 3 blade 19p 15 1/8 SS. I can hit 52 by GPS at 5200 rpm. I can pull 2 skiers easily with a full boat, but wouldn't mind sacrificing some hole-shot for the ability to hit about 60 mph top end (on a very smooth, empy lake ). I tried a 4 blade 20p, but hit WOT RPMs at about 40mph. I have a 3 blade 21p 14 7/8 SS that I have not yet been able to try.

Does anyone out here have the same set-up (350 mag, or 6.2L) with different props that I can use for calculations?
What prop pitch and diameter/ top speed by GPS/ WOT RPM and Drive ratio if you know it?
Are you happy with the hole-shot/ ability to maintain constant/precise speed when pulling skiers/wake boarders?
I've seen many talking about the high-five, they are a narrow diameter prop. Can anyone provide me with your perfomance figures on these?
Any performance numbers would be beneficial.

Thanks

_________________
Walt B
"Debt-Charged"
Black '07 H210SS
6.2L Bravo One turning a 21P HIFive
Wakeboard Tower with Perfect Pass Stargazer version
Missouri River; Kansas City, Mo.

I don't think you'll ever get better top speed results by going to more blades.

Even though more blades usually mean less slip, they also mean more drag at the same (prop) RPM.

I think most of the go-fast boats out there use 3 blade props.



Something was definitely wrong there.....assuming you have a 1.5:1 Bravo, you would have had to have almost 40% slip with 5200 rpm & 20p and get only 40mph you possibly had some cavitation?

The prop slip calculator doesn't really care how many blades you have. The slip number takes care of that. (I calculate out to 7-8% slip with the Bravo III .....57mph, 1.81:1, 26p, 4600 rpm) .......when I had the 460 King Cobra installed (1.43:1, 20p 3blade, 5100 rpm) It calculated out to about 12% slip at 60mph.

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1987 Four Winns Liberator 211, formerly OMC 460 King Kobra powered, replaced in 2006 by a 1997 Mercruiser 454/Bravo III

Well, that's what I thought previously. The bigger difference between these props was diameter. The 4 blade was only 14 1/8. Compared to 15 1/8 for the 3 blade 19p.

I think the 21p will work fine, but wondering if the 23p would still give me desireable results across the board.

I'm going to spend some time trying the two I have out to get better data as soon as the boat's back from the shop.

_________________
Walt B
"Debt-Charged"
Black '07 H210SS
6.2L Bravo One turning a 21P HIFive
Wakeboard Tower with Perfect Pass Stargazer version
Missouri River; Kansas City, Mo.

Of course, you'll lose top RPM with higher pitch props...... And it takes more and more torque to get the "taller' prop to turn the same WOT (top) RPM, which won't happen unless you were being "rev-limited " before.

Even if you only get about 4800 RPM with the 21 you should still run about 55 mph. With a 23 I would be surprised it you get 4600 WOT.

In that case, you're really lugging the engine. (is the WOT RPM for a 6.2 something like 4800-5200?) You never should have a prop so tall that it takes you below the recommended WOT range. Best performance is usually a pitch that keeps you just at or slightly below the top RPM without being against the rev limiter (with the boat loaded where you usually run it)

We are talking about stainless steel props, right? At this HP an aluminum prop might flex unacceptably.

When my brother had my Liberator ( and the 460 King Cobra inside) he tried an 21 pitch aluminum prop and it wouldn't even plane the boat!!!


Good luck.



Rick

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1987 Four Winns Liberator 211, formerly OMC 460 King Kobra powered, replaced in 2006 by a 1997 Mercruiser 454/Bravo III

Yeah, that's the limitation of the calculator - real world. It doesn't take into effect reduced WOT RPM from the higher pitch. I was hoping someone here had related experience I could use. I expect the 21 should do fine,without dropping below 5000 rpm WOT. As you said, that would be about 55 mph. I guess I'll just hafta try myself.

Thank all for the input!

_________________
Walt B
"Debt-Charged"
Black '07 H210SS
6.2L Bravo One turning a 21P HIFive
Wakeboard Tower with Perfect Pass Stargazer version
Missouri River; Kansas City, Mo.

After all the debate, I ended up going with virtually the same size prop as the stock. I bought a used ss for just under $300. I believe it's a Michigan Wheel. The only difference was it's a 14.25 and stock is a 14.75, I think. I'll swap it sometime this week just to make sure it's the correct fit, etc and that it's going to work if I need it.

_________________
2008 H210SS VP 5.7 Gi/SX
2011 Ford F150 FX4 EB

I am wondering if the different diameter will have affect?

I tried out my above mentioned 21p on Sunday. I hit the same WOT RPM and speed by GPS as with the 19p. It's like my boat has a 52 mph speed limit! I prefer the "tuning" of the 19p. By that I mean I am able to maintain a constant speed (for skiing) easier with the lower pitch. Hole-shot seems about the same, but then again, I didn't have two skiers and 7 peeps in the boat to really test it. Midwest propeller has the HighFive for about $400 now. I'm thinking of trading in my spare for one. Any recommendations???

_________________
Walt B
"Debt-Charged"
Black '07 H210SS
6.2L Bravo One turning a 21P HIFive
Wakeboard Tower with Perfect Pass Stargazer version
Missouri River; Kansas City, Mo.

Walt, our boats aren't the same, but they are close. Yours is a foot longer, but has more motor...

Mine is a 2008 200SS, with 5.7Gi/SX.

Drive ratio is 1.51:1
Prop is SS 14.75 x 21 (came with boat)
Elevation: ~720 feet
max indicated rpm is just touching 4800
max speed so far on gps is 57.9 MPH.


That day I had the bimini on (in the lowered position), 2 passengers, and about 1/2 fuel. I'm thinking I'll strip as much weight out as I can this summer and shoot for 60.

Good luck. I think finding a guy who would let you buy a few and return the ones you don't like would be VERY worthwhile.

_________________
2008 H200SS
5.7 EFI Volvo Penta
Black graphics
2004 Toyota 4Runner

I have the Gxi motor and the stock 14.75 x 21 SS prop.

55.5 on gps with full gas, quite a bit of gear and only me on board. I think I am also around 4800 wot.

_________________
2008 H210SS Yellow VP 5.7 GXi 320 HP (sold May 2010)
2008 Mercedes ML 320 CDI Diesel

Thanks jjker for the added info... I can definately use that! We should have the same HP, running same elevation (754'), and basically the same hull (the 210 is actually only 20' 10"), so your data should be usefull for my calc's.

_________________
Walt B
"Debt-Charged"
Black '07 H210SS
6.2L Bravo One turning a 21P HIFive
Wakeboard Tower with Perfect Pass Stargazer version
Missouri River; Kansas City, Mo.

Ok I read all the posts here about props, every little bit helps. My question is where are you fellas finding the prop diameter? Mine says this; QuickSilver 48 73982 A5 21P Its shiny like chrome so guessing that means stainless. I am new to this kind of boating but hope to learn fast.

1985 Horizon 190 Open
260 MerCruiser 5.7L Chevy 350 C.I.

I have lots of numbers from motor and out drive but not the slightest idea what they mean. A Service Manual is coming my way soon. Tom

Update on mine....
I ran my high-five this weekend. It's a 21p 13.25" dia. Got 48mph (GPS) with 3 pass and full fuel. Better hole-shot, as well as improvements in the turns. Much easier to maintain the 18-22 mph range as well.

_________________
Walt B
"Debt-Charged"
Black '07 H210SS
6.2L Bravo One turning a 21P HIFive
Wakeboard Tower with Perfect Pass Stargazer version
Missouri River; Kansas City, Mo.

Hello all,
Ok finally had the chance to take my new purchase out for some wot fun...what a great boat! Anyway wot stops fast at 4200 r's, engine data plate says 4200 to 4600. I don't beleive the speedo is correct and will get a gps reading one of these days, its plenty fast tho. Ok so now I want to get the rpms up nearer max wot. After talking to a prop shop am told my 21 needs to be 20 or I need to get either a 19 or 21 and have it re pitched to 20 which this shop can do so as to get the wot at or near 4500.

We ran 4-5 hrs all throttle settings and used 19 of 27 gallons of gas, not bad I'd guess for a 350 Chevy. Or is it? LOL

So I'm asking from you who have been around longer than I, is this a common practise, re pitching I mean? The prop man says so but I want to be sure. Have any of you here tried this?

Also how do I post pics of my prize here, I tried the avatar in user controls but it says pic to big? I see lots of members have pics posted in their replies. Tom