Acme 540

I'm going to be upgrading the prop on our 2001 in the spring and I wanted to get feed back on anyone that is using an Acme 540 on their SN 2001. Based on its specifications it should give considerably better performance than the stock 13x13 that is on the boat now.

LOL, try a search... very popular upgrade. Id say that its the prop to have on a 2001 (1:1) as far as all around performance goes. There are a few other options if you run heavily weighted.

Disclaimer: I dont own a 2001, but have driven many- including a few with 540's. I run a cut down 540 (1210) on my Skier, and will be running a 540 on my '80 Ski Nautique next year... so Im *almost* qualified to comment.

In my experience its quicker out of the hole by a good margin, and holds about a 1mph advantage up top as compared to the stock 13x13 Federal. Its also smoother than the hand finished props and bites harder in turns. The (2) 2001's Ive driven with it spun spot on 4400 RPM, so right where you want to be.

I've got one on my 86. Better hole shot, pulls great, way better than stock, close the throttle and its kinda like putting on the brakes.
I'm happy with it and recommend it as an easy up-grade.
The boat also has ported GT 40p heads,roller rockers, Cam Research cam, Weiand Steath intake ect...
I think Acme runs a winter deal in January on all there props.

Tims a little modest he knows as much about props as anyone and a crap load more than me.

Are you using the boat mostly for skiing? Seems like the 540 is definitely the way to go for that application. I upgraded to the Acme 542 (slightly lower pitch) on my 2001 from the stock Federal 13x13 this summer as we use the boat mostly for wakeboarding with 1100lbs or so of ballast on board. HUGE difference over the stock federal, much better holeshot and holds speed better WITH ballast than the stock prop did WITHOUT. I love it! I've also driven and skied behind Mark Mel's 77 Nautique with the 540...was very impressed...also awesome holeshot and pulled great at both skiing and riding speeds. I would say that if you do any footing, you probably want to go with the 540 and not the 542. We did a bit of free skiing with the 542 on my boat and it seemed ok for that as well, certainly awesome holeshot for skiing. I have a bone stock PCM 351 for power.

seems to have a little more bow rise than before but not anything significant.

Bow rise on acceleration, or a more bow up trim angle? The 540 has a 7 degree rake while the Federal is 0. I was hoping to gain a little bow down trim angle with that prop.

The boat is general use, the MC is the primary slalom boat, but it is probably 60 40 wakeboard to ski usage for the 2001.

yes the 540 and 542 rise the bow, it's the nature of the animal. It seems the OJ does not and even the old Acme (4 blade) 208 didnt.

I've had a 542 on my 80 for 3 years now.

MIskier wrote: Bow rise on acceleration, or a more bow up trim angle? The 540 has a 7 degree rake while the Federal is 0. I was hoping to gain a little bow down trim angle with that prop. The boat is general use, the MC is the primary slalom boat, but it is probably 60 40 wakeboard to ski usage for the 2001.

Generally speaking, Acmes tend to run a little more bow high at speed. If you want to plant the bow, get an OJ. The Acme will be the better all around prop in terms of the boat's performance though (holeshot, speed holding, top end). Planting the bow will give you an incrementally better slalom wake... but the 2001 is not exactly the best course boat out there either way. A little bit of weight in the bow would likely accomplish the same thing.

What information are you considering to be inaccurate?

Positive rake = aft rake = bow lift, no? I know that Acme's have a bunch of aft rake, which also has the benefit of increasing prop to hull clearance.

If Im not mistaken, all of the Acmes Ive had my hands on have a good bit of aft rake. Relative to the other props they make, you may not have many options on how much rake you get. My guess is that they made their recommendation based on what would perform best on your boat... which is why they pointed to the 540. I cant envision even the worst salesman (or product engineer) saying "Oh, you should go buy an OJ" when posed with your question. Its part of being an informed consumer!

As far as the offerings from OJ go, they will have 13x13's in both 3 and 4-blade flavors. They do not currently offer any 1:1 RH props in their XMP line though, so you'll only have the hand finished option. Theyre not bad performers, and may help bring the bow down a little vs. the Acmes, but theyre a tick behind performance-wise, IMHO.

Now, Over-My-Head has an 87 and Ml-skier has an 86, slightly different weight distribution there, right? Not sure if that's relevant here, but you may not both be coming from the same baseline. Both boats start off with the same OEM prop?

Also, lifting the bow slightly could increase top end performance right? How about wake-boarding wake? It seems like most wake-boarders are trying to get their sterns squatted a bit.

Brian, that is correct- the '87-88 boats tend to be ~2mph slower than the 82-86 versions, probably because of the forward weight shift (dash, driver, etc). Stock props should be the same on both, though (13x13 Federal/Michigan Wheel), and thus, should be affected similarly by swapping to a 540.

Yes, the slight bow-up attitude that the Acmes lend is probably what gives them their 1mph advantage up top. The difference is VERY subtle though- I cant say Ive noticed it myself- and I like to think Im fairly aware of such things.

Ive spent some time in a course behind a 2001, and I can tell you that a prop change isnt going to transform one into a world class slalom machine! If you want to really make a noticeable improvement in the wake, try lightening the boat up. Joe has reported that his '83 has a much improved slalom wake after going on a diet. Short of a full structural rebuild, keep the gas tank below half and maybe put a few lbs in the nose of the boat. SkiBum also tried adding a temporary lip to the keel and had some success in getting the boat to plant the nose and improve the wake... too much will make the boat bow-steer at speed.

Luch, how would a shop go about changing the prop to make it lift the transom? Certainly theyre not going to alter the rake.

Im also curious how a prop changes wake hardness... perhaps you mean the firmness of the rooster tail? I can see that changing as a function of pitch (more prop RPM at a given speed = firmer rooster).

The 208 does have slightly more pitch than the 540, 12.5 vs 12.
http://www.acmemarine.com/prop-list_ski-boat.php
Whether or not that would lower the RPMs enough to soften the wake, I'm not sure.

That was one of the reasons for the creation of the 1.23:1 vs. the 1:1, right? To lower the prop RPM and therefore soften the wake?

David, two boat at a given speed, say 30 mph, the boat with the 1.23:1 transmission will have a lower propeller RPM than the boat with the 1:1.

But, the propeller on the 1.23:1 boat will have more pitch on the propeller to make up for the slower RPMS.