1992 SN pro boss which prop?

[Rlbol]

I am going to order a new prop before the sale ends today, but I am not sure which one to order? It is a 92 SN with the pro boss motor. hull is not weighted down and boat is a family ski boat and used for everything from barefooting to wakeboarding and everything in between. So I guess i am looking for just a good all around prop.

[DavidF]

RE: 1992 SN pro boss which prop?

I have an ACME #422 on my '93 SN as that was the best all around prop back in '05. However, ACME may now have a three blade prop that is better (they didn't in '05). You should call ACME and discuss your situation and get their recommendation...they know what they are talking about.

[mndanielsncsu]

RE: 1992 SN pro boss which prop?

I agree with David... I have the Acme 422 on my '93 Sport with the Pro-Boss and like it, but have heard that the new 3-blades perform better. The 422 is great out of the hole though.

[TRBenj]

RE: 1992 SN pro boss which prop?

The 1442 (13.25x15) 3-blade is the prop to have on that hull with the HO engine. The 422 is a decent prop, but I prefer the 612 or the 1442. Trust me, Ive tried them all.

[mndanielsncsu]

RE: 1992 SN pro boss which prop?

Tim, I didn't realize you collected props.

Out of curiosity, what is the advantage of the 1442 versus the 422?

[brittcrowell]

RE: 1992 SN pro boss which prop?

So How do I know what engine I have in my '93 ski?
I know its got the electronic ignition.

I'm not happy with the 470 (I was in Colorado though) So I'm thinking the 1442 might be the way to go.

Bummer it looks like I missed out on some sale somewhere too.

Thanks Britt

http://www.planetnautique.com/index....mp;pic_id=1991

[TRBenj]

Re: RE: 1992 SN pro boss which prop?

Britt, in looking at your graph you seem to be implying that the 470 is getting you to 48mph @ 4300 RPM? Something is very wrong with those figures- either your tach or speedo are way off. Take some pictures of the engine so we can help you ID it- and grab the model number off the tag on the intake manifold.

Whats wrong with the 470? The only possible downside I can think of is the increased RPM's (~200) may hurt economy slightly. The performance improvement is definitely worth it though, IMHO. FYI, the 1442 wont turn too many fewer RPM's than the 470. If youre looking for economy, you might want to look into purchasing a sailboat. Yellow_Flash_Colorz:

[brittcrowell]

RE: Re: RE: 1992 SN pro boss which prop?

Mom gave me a sailboat a few years ago. It needs some gelcoat work, I'm way to lazy for that and poor to pay someone else.
They very well may be something wrong with my tach. I don't doubt that my speedos are off too. Need to borrow a friends GPS to check I guess.
I thought the RPMs looked low when I dug out this file the other night. But I found the original data in a old notebook and its indeed what I originally wrote down.
I've got a cousin with a high end Fluke thats a mechanic, we can check the tach with that.
I was originally worried about turning too many RPMs with the 470 when I moved back to AL from CO, but I guess thats not the case?
What RPM should I not go over?
So how many RPMs should I be tunning at WOT?

The engine model number is: PLP-PR-R12PT
According to a post of yours on CCFans TRBenj, I have a left handed ProBoss engine mated to a 1.23 tranny.
So is thats the 285hp model?

Thanks Britt

[TRBenj]

RE: Re: RE: 1992 SN pro boss which prop?

Britt, thats correct- you have the 285hp Proboss. Do get a GPS on there, the 48mph is possible, but probably a tad optimistic. If thats in the ballpark, 4300 is definitely way off the mark. I would expect you to be turning that prop close to 5000 RPM. The recommended max WOT RPM for the HO 351w is 4800, so youre not much beyond that. The 351w has a strong bottom end so I wouldnt worry about it- I turn mine 5200+.

At sea level, Id probably give the nod to the 1442 over the 470 for the HO 351w like youve got- but the difference in performance and RPM's really doesnt justify purchasing another $300+ prop. The 470 should still perform great!

[mf01]

RE: Re: RE: 1992 SN pro boss which prop?

Are most of these opinions based on an unweighted boat? I'm assuming that based that this is for a Ski.

I was thinking the 470 for my SPN, but I weight it a little. Skidim recommends a 470 for 1500+ lbs, but I usually run around 1200 with crew and ballast. Anyone have any opinions on the weight and prop? Also, I'm curious what RPM's I'd turn while cruising (30mph).

I had a few extra people in it this weekend and my stock prop seemed sluggish.

[brittcrowell]

RE: Re: RE: 1992 SN pro boss which prop?

mf01,
I have a '93 ski with the 285hp.
I got the 470 years ago when I was in Colorado and doing more wake boarding and using a fat sack too. I didn't get it on purpose. During the a drought in CO the day before they closed the lake, we found a shallow spot. 5K damage. July 16th, all around quick end to the summer.
Few months later when I got the boat back, we went down a few thousand ft in elevation to a lake in Nebraska. First time I tried to get up on the salom ski, in good CO form, the driver gave it all he had after tightening up. Snatched the rope right out of my hands!!! The next summer back on the lake in CO with weight and people in the boat, the wake boarding speeds were much more manageable for a less skilled driver and me too.
Now that I'm back at sea level and not doing any loaded driving, I find the 470 to be a bit much. I don't like the higher RPMs/noise at cruising speeds and I can tell I burn a lot more gas (Wish I had a way of measuring that too).
So last summer I stole my buddies stock 14x16 prop off his '89 and put it on my '93. I noticed the reduction in noise and gas usage. However I did notice with a boat load full of people that it was sluggish getting out of the hole and in the wake board zone. But when its just my wife and I , 75% of the time, I like the stock prop better for the kind of boating I'm doing these days.
Britt

[eklock]

Re: RE: 1992 SN pro boss which prop?

The 1442 (13.25x15) 3-blade is the prop to have on that hull with the HO engine. The 422 is a decent prop, but I prefer the 612 or the 1442. Trust me, Ive tried them all.

ACME has recommended their 1492 (13.5 x 16) for my '91 SNCB with 240hp/1.23:1 drivetrain. They told me that the 1442 was developed for 1:1 transmissions and the 422 was desigined for higher RPM motors like the PB or GT40.

I am about to go insane trying to decide on a new prop. 1492, 422, 1442, 470 or even the 1490. all I want is a marginal increase in acceleration (holeshot) without killing my GPH by revving the motor 300-500 rpm's across the board. If a prop is advertised as 'more efficient' shouldn't it turn fewer RPM's at any given speed than a 'less' efficient prop? Propellers are about delivering thrust, right?

[TRBenj]

RE: Re: RE: 1992 SN pro boss which prop?

Id love to try that new 1490, but it sure sounds like a monster prop. I fail to see how something with that much pitch is going to improve performance- I imagine it would cut revs and hurt holeshot. Either that or the 422 would be your best bet if you want a low rev'ing prop though. The shorter 3-blades will likely outperform them, FYI. And I think you and Bill got your wires crossed- no way was the 1442 designed for a 1:1! Its currently my favorite prop for 1.23 boats that can turn it (pre-1997).

As far as efficiency goes, youre right about delivering thrust. Instead of fuel efficiency, I use the word to describe the slip %. For example, the 13x16 OJ Legend and Acme 422 4-blades both turn similar RPM's on my '90 (~5k at WOT). The Acme has an advantage in acceleration and top end though- so it does a better job of turning those RPM's into speed- thus more efficient.

[mf01]

RE: Re: RE: 1992 SN pro boss which prop?

I'm kind of in the prop debate myself. I have a Sport instead of Ski, so I'm leaning towards the 470. I'm worried that it might burn more fuel at cruise than my stock prop, so I've also looked at the 422. I mainly wakeboard, but still use the boat to cruise up to restaurants.

[eklock]

RE: Re: RE: 1992 SN pro boss which prop?

TRBenj- Thanks for the knowledge and comments. I don't carry any ballast other than passengers, usually 3 adults and 2 kids (one being the rider). The wakeboarders in our group are kids weighing less than 100lbs on 139cm boards; they come up effortlessly with the stock 14 x 16 Federal. When pulling 200+ slalom skiers out of deep water a little extra bottom-end would be nice. What difference would I see with the 422 compared the stock prop?

I'm thinking that the 1490 or 1492 wouldn't be much different than the stock prop. I'd really like ACME to make 3-blade prop with the dimensions of the 224 (13 x 15.5).

Where do you estimate the RPM's would be at 20 and 35mph with either the 422 or 1442? I bought the boat new in '92 and have only put 400hrs on it in 17 years. In that time I think it's been WOT about a half dozen times. There's better boats for going fast if you know what I mean. Like mf01, we spend a fair amount of time cruising to restaurants and pleasure cruising.