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CharleyAMN

Propellers for a Beginner!

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CharleyAMN

I have a 2013 VTX. Paperwork says prop is a "High-Altitude (V-Drive 14.5 X 14.25)". I have no idea what that means.

I live at 800 feet...hardly high altitude.

It seems the RPMs are quite high in all phases and all weights (compared to my former TXi). And it seems I have to run the engine at almost max to get a 32 mph slalom speed. On top of that the rooster tail at all slalom speeds seems to be quite far back.

So will someone who knows something about props and about the VTX educate me on whether this is a proper prop for me and if not, what I should be looking for? I do want the slalom ability along with the surfing ability. We don't really wakeboard.

Thanks!!

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mikeo

Take a look at the hub of the prop and find the number on it, that will tell you exactly what you have. Then compare the numbers on the prop to the handy guide posted at WakeMakers:

http://www.wakemakers.com/malibu-wakeboard-boat-propellers

Also take a look at the prop database linked under "resources" at the top of the page, and search the forums for others using the same prop you have. Everybody seems to have an opinion on what prop works best on their boat for what they're doing. Your best bet is to get some data logged: speed, RPM, load (ballast), etc. in 5 MPH & 500 RPM increments all the way up to WOT. Once you have the data, then you can make changes and figure out what works best for you. Don't forget to account for the weight of fuel and passengers when you log your data!

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oldjeep

Should be a 1235

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shawndoggy

I think Malibu does a disservice by calling a prop "high altitude." It's really just your boat's final drive ratio. You don't order a "high altitude" rear end on your truck, but you might pick lower gearing.

CharleyAMN, how do you use your boat? Sounds like skiing for sure, but anything else?

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oldjeep

So you are saying that at 32, you are full throttle? Even with a 1235 that boat ought to do around 40.

If the MN in your username means you are in MN, I could lend you a spare 1939 to try out, that is what I run on my 2012 vtx.

As far as the rooster tail, you might try experimenting with a couple hundred lbs of bow or center weight. I typically run almost a full bow tank when skiing, although without it there is just a soft hump that doesn't really impact my skiing.

Edited by oldjeep

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REW

Do what mikeo says then call Acme and/or OJ and talk to them about prop recommendations, they will have a better understanding of what you need to get the best out of your boat. The prop you have is for heavy weight or those guys running in the mountains 3000'+ elevation.

http://www.acmemarine.com/contact_us.php

http://www.ojprops.com/contact

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REW

I think Malibu does a disservice by calling a prop "high altitude." It's really just your boat's final drive ratio. You don't order a "high altitude" rear end on your truck, but you might pick lower gearing.

CharleyAMN, how do you use your boat? Sounds like skiing for sure, but anything else?

I agree however most people do not understand "final drive ratio".

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jtryon

i always think that a prop described as "high altitude" is just a lower-pitched prop for wakeboarding/surfing, to handle more weight.

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robbennett

The question we need to ask is do you only slalom or do you ever weight for surfing or wakeboarding?

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oldjeep

He says in his first post that he wants to ski and surf.

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Bozboat

I agree however most people do not understand "final drive ratio".

It helps me to think of the pitch of the propeller in terms of a ten speed Schwinn. More pitch is like gears five thru ten and less pitch is like gears 1-5.

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CharleyAMN

I'll get out and do some logging.

In the mean time, to be clear, we are looking to surf, to ski, and to do some basic kneeboarding.

Thanks for the info!!!!!

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shawndoggy

How much ballast do you run surfing?

This is a good read from indmar directly about how much prop you need: http://www.themalibucrew.com/forums/index.php?/topic/39176-dont-kill-your-engine/

If you are used to a ski boat with a 100rpm=1mph sort of ratio, you are probably going to feel pretty wound out with a wakeboard/surf prop. But those props are really necessary to use your boat to surf with extra ballast. it's a trade-off.

1235 should be good for 42 at WOT I'd think, which should be plenty to ski (it's just you'll be skiing at 4300 rpms instead of 3200).

1273 is same diameter and pitch but a bit more cup and would reduce your rpms some.

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mkpursehouse

Crew

Can someone help me with prop selection for my 06 Vride with 320LCR engine. I currently have a 537. I'm a Recreational skier doing everything from Wakeboarding, skiing & Barefooting (2-3 up). Ideally i'd like a little more top end speed, but also don't really want to compromise my holeshot.

From research, below are the 3 props which appear to meet my needs, I just don't understand the impact when changing pitch between different diameter props.

Wakemakers website suggests the 1941. I believe that the 537 was stock for my model. I am currently happy with my holeshot but would like to increase top end a little, but still want to retain torque throughout the range.

I have been told that when increasing diameter you decrease pitch. Can someone explain what the different outcomes would be for each of the below props with regard to top end speed & holeshot. (assuming nothing else changes with regard setup of the boat)

Part # DIA Pitch Cup

537 13.50 16.000 0.105 cup

1939 14.00 15.500 0.105 cup

1941 14.50 15.500 0.105 cup

Thanks

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shawndoggy

^^^ just stick with the 537. It's about as good as you can do for an all-round prop on that hull.

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williemon

My 01 SSVLX came with a 537. I did not really like that prop. I'm still not sure which prop I will stick with but right now I'm using an oj 905 wake pro v. It is a 14.75 x 15.25 I believe. So far it does pretty good. In testing with just me on board, 1/2 tank fuel and no ballast I run 30 mph at 3250 rpm, 32 mph at 3450 rpm, 36 at 3900 to 4000 rpm and 40 roughly around 4500 rpm. The engine will run up to and over I bet if I let it, 5000 rpm. After 40 mph the boat and engine really lose steam and the speed increase is less. So far it is working pretty well but I wonder if there is a prop that would give a bit more neck snap at holeshot but not run more rpm for each speed. I like to slalom as well and have kids that ski. Wakeboarding is high on the list too. With 4 adults and two kids on board, 20 to 23 mph comes in at roughly 2700 rpm. Tubing is included in that as well. I'm not sure what rpm surf speeds come in at. I don't have any numbers on the 537 but it did not hold water well and would be slow getting up to speed, kinda like a clutch slipping. I've read that a acme 1273 runs close to these same numbers but I done know how to compare holeshot between the two. I'd like to try that one.

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CharleyAMN

Someone asked how much ballast I run surfing. The answer is 100% in all four tanks.

Haven't done logs yet, but when pulling a slalom skier this morning with 100% front ballast, 1/2 tank of gas, and an observer, it took 3700 RPM for 30 mph (as measured on my iPhone GPS since the paddle wheel seems to be 2 mph slow).

That seems to be a high RPM.

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Nitrousbird

^^^ just stick with the 537. It's about as good as you can do for an all-round prop on that hull.

1939 has the same top end with better pulling power...the 1939 replaced the 537 for later Malibu's and is a better prop. That said it won't be a night and day difference by any means.

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williemon

3700 rpm for 30 mph hurts the wallet. It would be fine for me though if I only did it once a month, but I like to get in several open water slalom runs a weekend. Also since the wake is better than my old I/o, I'm leaning to run 32 mph for smoother wake and better feel on my slalom. I did see charts on the net that show Rpms above 3400 or 3500 really suck the gas much quicker. I used to run 4000 rpm on my 3.0l mercruiser 17 foot I/o to run 30 mph but it used much less gas.

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oldjeep

We're headed out in a few minutes. I'll try to remember to.look what rpm we are at for 32mph with a 1939

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oldjeep

On my 2012 vtx with a 1939 and 3 people in the boat we were getting 3200 rpm at 32 mph verified with the GPS on my phone.

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williemon

I will ask here in this thread since I think it would help in this discussion. If the brand, pitch, and cup remains he same, how does going from a 14 or a 14.5 diameter to a 15 inch diameter affect holeshot and RPMs at particular speeds given a v drive boat with a standard 350 like the monsoon loaded only with fuel and 4 to 8 passangers regardless of activity? Would it be the same all around no matter the passangers load such as holeshot is slower as you add more passangers? The same holeshot quickness as loaded with only 2 passangers even if there are 8? Decreased holeshot and or speed for the rpm due to the extra drag? Just wondering if in some cases of doing several sports but not heavily weighted, is a larger diameter prop overkill and it's value not noticed or even a performance degrade?

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oldjeep

I will ask here in this thread since I think it would help in this discussion. If the brand, pitch, and cup remains he same, how does going from a 14 or a 14.5 diameter to a 15 inch diameter affect holeshot and RPMs at particular speeds given a v drive boat with a standard 350 like the monsoon loaded only with fuel and 4 to 8 passangers regardless of activity? Would it be the same all around no matter the passangers load such as holeshot is slower as you add more passangers? The same holeshot quickness as loaded with only 2 passangers even if there are 8? Decreased holeshot and or speed for the rpm due to the extra drag? Just wondering if in some cases of doing several sports but not heavily weighted, is a larger diameter prop overkill and it's value not noticed or even a performance degrade?

Theoretically :)

Same pitch and cup would produce about the same results (subtracting some performance for the additional rotating mass of the larger prop) if the smaller diameter prop is not cavitating.

If the smaller diameter prop is cavitating then the larger diameter prop would have a better shot of taking off cleanly.

The larger prop would have a better shot at getting a larger load moving without cavitation.

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shawndoggy

In my experience:

smaller props result in more top speed (all things being equal).

larger props start to feel like a pitch change the bigger you go. Turning a 15" prop you have to step down in pitch to get similar performance. At the same pitch a 15" prop will seem "taller" than a 14.5 or 14 performance wise.

larger props do much better with holeshot and holding speed, but they run out of top end faster.

the larger the prop, the more the prop yaw (boat's tendency to be "heavy" on the goofy side and "light" on the regular side)

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