Prop question

Hi there, am running a Malibu VLX with a 340 Monsoon. Twated my prop this year and need to get a new one. Can anyone advise me on the best prop for my boat in regards to fuel consumption?? The boat is souly a Wakeboard boat and therefore has no need to be a dragster or breaking any records in speed!!

Your best fuel consumption would be to only run it in idle speed. Especially since speed is not an issue

Just kidding. Call the folks at Acme and they can advise you on what would be best for you based on the boat, engine and how much weight you run.

13.5 X 17 for replacement.
I think Karl once recommended 14 x 14.5 for upgrade?
Slower but great big pull for full ballast. Call him boarditup.com

Depends on how much ballast you run, what kind of hole-shot you desire, and how much top-end you want to sacrifice. I believe Acme make the following props for your boat:

381: 13.5 x 17.5 (stock)
537: 13.5 x 16
857: 13.25 x 15.5

Doesn't the Monsoon come with the 537? I thought the 381 was only on the Hammerhead.

Most run the 537. If you have a lot of ballast, run the 857. Your best fuel consumption will be where the torque band is for the speed you want to run. That may mean a lower pitched prop for you application.

Guys seriously that is so much help thank you!! I'm pretty sure the standard prop with the monsoon is the 13.5 x 16. The boat is pretty loaded with 5 - 7 people on average 700Ib in the rear ski locker and about 400Ib in the bow!! With the wedge down it also adds more weight. So i am none the wiser really?? ha ha. I don't mind sacrificing top end but i am planning to take the boat on a 4 month road trip over the summer, putting about 400 - 500 hours on the boat which accumilates to a lot of fuel!! So just a little difference could save me money!!

Get two diffferent props and experiement with your boat. Save the prop that does not work as well for most of your applicaitons as a spare. Keep the tools and hardware necessary to change a prop on the boat at all times. What you will find is that at different altitudes, ballast weights, and preferred rider speeds, that one prop will be favored over the other. At high altitudes, a lower pitch is required for decent performance since there is less air pressure.

That is super useful as im going to my parents place on Lake Annecy in the French Alps, which is about 2500 feet above sea level!! The idea about 2 props is another cool idea!! Stupid question, What is the point of a low pitched prop??? Surely the engine will have to rev much higher to get simular performance to a high pitch prop, too much pitch and the engine will bogg down (Like starting a car in 4th gear???!! Is that right or am i just completely stupid???????????

No, you understand. Just like car gearing. Please keep in mind that water is unlike the pavement - it flows. Obvious, but the implications in terms of performance have many more variables than a car. In terms of the prop, you have number of blades, blade shape, material of construction, diameter, pitch, rake, and cup. Your hull will have different characteristics on loading. Your motor will perform different at each 500 foot change in altitude.

Having different props allows for different performance like a transmission does on land.

I get you dude!! Basically i need help!!!

Get a 537 and an 857. Run the 537 normally, the 857 when loaded heavy or at altitude above 1,500 feet.

I have a question, how does alltitude play a variable in prop pitch selection on a boat?

At sea level there is about 14.1 psi all around. Ath higher altitudes, there is less. The engine develops less hp but still has to perform the same work. The lower pitch prop allows good performance with the lower hp produced.

Karl--which is better, Acme or OJ? Why? I am not trying to start a war, just want some general information. Malibu used to use OJ, now the VLX comes with Acme--just wondered why. Also, a friends Supra SSV came with a 13 x 15.5(not sure the manufacturer) that performed extremely well.

how much horsepower drop are we talking about? Lets say a 265hp PCM motor at sea level(14.1psi)dyno tested by correct craft in Florida, then running at 3000 feet above sea level? How much hp are we losing here....exactly.

Chuck, just a note, Acme CNC machines all of thier props, 100%. OJ CNC machines thier XMC prop only, the rest are the cast/polished props, the old way of manufacturing.

Go to www.Acmemarine.com and www.ojprops.com to verify the products if you have time or interest.

The exact hp depends upon the motor. I don't know the curve on yours, but I would expect about 10-15 hp.

I sell Acme props. I am biased. However, the 3-blade Acme that I put on my X-9 in place of the 4-blade OJ made a noticiable difference in hole shot and the top end was about the same. Less expensive, too.

Karl, what prop would I need for a 04 VLX with 340 hp and about 2800 lbs?

just to note, I sell both Acme and OJ props as well.

Karl, I did a little elevation research for you. Typically we wakeboard on Chestemere Lake, elevation, 3440 feet above sea level. Also, we wakeboard at Cypress Hills Park, elevation, 4820 feet above sea level, a difference of 1380 feet. I have yet to be able to differentiate in the difference in performance of my 1980 Ski Nautique, with 265 HP yet. OR my brother's 89 Malibu Skier. IT IS VIRTUALLY IMPOSSIBLE TO TELL THE DIFFERENCE. If you were running a 6000HP Funny Car dragster at Mile High in Denver vs Seattle Washington.....yeah you would definately see a remarkable difference in performance. However, when you tell these guys to buy two(2) props becuase of performance difference in thier boats due to elevation.....dream on. Stop BS'ing these people.

I run an ACME 3 Blade, 11.5 X 13. The pull is exactly the same on both lakes. You're full of crap.

It depends upon the boat and the load. If your loading is such that you are using all of the available hp and torque, you will notice it. If you are not using it, you will not notice the difference. Propping is not an exact science because of the number of variables. That is why we depend upon experience and feedback from users and not pure mathematics. The question was about sea level and 3,000 feet above sea level. I have sold many props to people who move from sea level to higher elevations. It depends upon the person and how particular they are about the performance of their boat.

Thank you for the comment on the contents of my large intestine....


Woody - Most guy are happy with the 537 for your application.

A buddy of mine just got a oj (pretty sure it was an oj and not an acme anyway), I believe the size was around 14x14 or 14x141/2. What a difference from stock. His boat is an o3 malibu lsv with monsoon engine. I think his general ballast is around 2200-2500lbs before wedge. With the stock prop the boat was a PIG! Now, with all the ballast and wedge down it is unbelievable. It doesn't take anything to get it on plain, and when up to tow speed around 23-24 miles an hour it is only turning 3300rpm as before it was turning about 3200rpm. He hasn't had it out enough to really check fuel consumption but I think the trade of in easier take offs will make up the extra 100rpm when towing. We'll see. The next day it isn't pouring around here we'll check it on my 04 LSV.
Oh yeah, he definantly lost some top end but it is plenty fast for what he uses it for....RIDING!

Eric from OJ PROPS here. We built the prop Chris is talking about last year, 14.25 X 14 LC XMP EGDE part #466, specifically for the V-Drive heavily loaded wakeboard boats. This propeller was tested by several of the top pro riders with most of the major boat builders with very good results. It has been standard on the Skiers Choice line of wakeboard boats. The XMP EDGE is a much better option over our 13.7 (or 13.5 for the Acme) X 16 propeller that has been the standard fix over the years. Yes, you may lose some top end, 1-2 MPH from the testing we have done but the increase in low end makes up for it.

We do fully CNC machine 90% our propellers. We still offer our hand finished line of propellers as we have for the last 70 years.

I'm not here to get in a OJ VS Acme debate. I respect the guys over there and feel we both make propellers that work similar to each other in performance. If one were to test the same sizes from each of us you would find not much difference in boat performance. There may be some difference in wake characteristics due to differences in blade designs but the numbers would be very close. However, when an OJ 4-blade, CNC machined or hand finished, is replaced with a 3-blade, OJ or Acme, the 3-blade should outperform the 4-blade. An apples to apples comparison is the only fair test.