ACME 13x12 vs. OJ XMP 13x12

[mlange]

As long as the weather is half way decent, I'm going to be putting the boat in the water next weekend, so I'll definitely post the results.

Mike

[doughickey]

As long as the weather is half way decent, I'm going to be putting the boat in the water next weekend, so I'll definitely post the results.

Mike

<{POST_SNAPBACK}>

Thanks Mike. I'll keep my credit card tucked away until after your tests.

[doughickey]

As long as the weather is half way decent, I'm going to be putting the boat in the water next weekend, so I'll definitely post the results.

Mike

<{POST_SNAPBACK}>

Mike, I'm also considering the Prop Puller tool kit. I've never swapped my prop before... want to do it right.

So, if you bought their kit, or have other suggestions, I'm also interested in your advice.

Looking forward to your results. Thanks again.

[edwin]

BTW - in line with this thread, I saw the local promo guys' 05 RLXi last weekend. According to him, Dennis Kelly at Malibu (heads up promo peeps) has spend a bunch of time testing ACME vs OJ XMP for the 05 RLXi promos. Final answer is that the OJ XMP 13x12 produced better ski wakes than the ACME hence all 05 RLXi promos will be running the OJ XMP this year.

[doughickey]

BTW - in line with this thread, I saw the local promo guys' 05 RLXi last weekend.  According to him, Dennis Kelly at Malibu (heads up promo peeps) has spend a bunch of time testing ACME vs OJ XMP for the 05 RLXi promos.  Final answer is that the OJ XMP 13x12 produced better ski wakes than the ACME hence all 05 RLXi promos will be running the OJ XMP this year.

<{POST_SNAPBACK}>

Edwin, thanks for the added info. I can't wait to order..... just gotta decide if it's 11.5" or 12" pitch. I hope Mike has good weather this weekend!

[mlange]

That's real interesting - that tells me that Malibu had to pay to get the RLXi recertified for 2005 with an OJ prop instead. I know there's an official list out there of what boats are tournament approved along with their setup. That also means the RLXi w/ and ACME would no longer be tournament approved. Not that any of that means anything in real life.

Where's rutat when we need him.

Mike

[mlange]

Sure enough!

The RLXi is approved w/ 4 different props this year and PP 6.5n.

Found it at http://www.usawaterski.org/downloads/2005A...vedTowboats.pdf

[doughickey]

Sure enough!

The RLXi is approved w/ 4 different props this year and PP 6.5n.

Found it at http://www.usawaterski.org/downloads/2005A...vedTowboats.pdf

<{POST_SNAPBACK}>

Mike, thanks for the AWSA link. Does this make you the new Googlemeister?

[mlange]

Hope not.

Ok, I forgot my GPS today, but I did finally get to run the XMP 13x11.5 prop. For those of you following along, I had the stock 13x13 SS CVP before.

The first mistake I made - I wish I had started out with the stock prop for a bit and then put the XMP on, since it's been 6 months since I've been out in the boat and wanted to have a fresher memory on how the stock prop was.

In any case, the following are my observations:

I immediately noticed - surprise, surprise - how much quicker the boat jumped out of the water. There is almost zero bow rise. I usually like to get pulled out very quickly and have my driver go to full throttle, but I can already tell this prop is going to rip my arms off if I keep doing that.

Secondly, this prop really bites if you're moving along around 30 mph and hit the throttle. The CVP would slip a bit and then get you up to speed slowly. With the XMP you can really feel it when you ask for more.

Surprisingly enough, I did not notice a big difference in how smooth it ran. I have a hard time believing it isn't a lot smoother than the CVP, so I'm guessing this is just because I wasn't able to run the two props back-to-back.

I was a bit disappointed in two things : mfg quality and top-end speed. I lost probably 1-2 mph from the CVP. Like I said, I forgot my GPS, but my speedos showed me doing between 46-47 @ 5000rpm whereas last year it showed 48-49. Also, while I wasn't surprised by the sanding on the back of the blades for balancing, I was surprised at what looked like a few little nicks on the tips of the blades. I'm guessing this is from where the NiBrAl material chipped away a touch when the CNC machine was doing the tip.

Overall, I'm happy with the decision to go with the 13x11.5 because of the gain in hole shot. However, I think if I were to do it again I'd probably go with the 13x12 instead.

I can't speak to the ACME, since I've never ran it. However, if someone were to ask my opinion on whether to go with the XMP 13x12 or 13x11.5, I'd suggest to go with the 13x12 if you barefoot at all, otherwise I'd suggest going with the 13x11.5.

Mike

Edited May 1, 2005 by mlange

[doughickey]

Mike, I really really appreciate your thorough report. As I mentioned earler, my original plan last fall was to move up from my 13X13 CVP to the ACME 13X13.

Then.... based on The Crew threads, I decided the OJ XMP was the better way to go.

Essentially, I've been sitting on the fence between the 12" pitch and the 11.5" pitch.

Your report and my projected needs has nailed it for me. I'm going for the 13" X 12". (I used to get 48.5 - 49 mph @ 5000 rpm with the CVP.... but I wanted to getthe revs down a bit. Redline in 1998 was supposed to be 4800 rpm. I know 88 said the current 310 carb is supposed to have a 5K redline...., but I like to work this side of it. (The mfg quality has me a bit concerned however...)

Again, thanks a lot.

I'll order next week..... but I haven't even pulled the boat out of storage yet.... will be mid June before I get to test. However, when I do, I'll be sure to report the statistics!

Again, thanks so much for all the info.

[88Skier]

Something else to consider Doug. My manual says when your boat is unloaded, your rpms should be a little high, 200+-, so that when it is loaded down and you open it up, you won't be lugging it down. RTM, yours may say it also.

[martho]

Finally taking the OJ XMP 13x12 out tonight.

I will have data later

[skisix@38]

BTW - in line with this thread, I saw the local promo guys' 05 RLXi last weekend.  According to him, Dennis Kelly at Malibu (heads up promo peeps) has spend a bunch of time testing ACME vs OJ XMP for the 05 RLXi promos.  Final answer is that the OJ XMP 13x12 produced better ski wakes than the ACME hence all 05 RLXi promos will be running the OJ XMP this year.

<{POST_SNAPBACK}>

All (3) 05 promo's in my area are already out and have the ACME under them. And the tests for tournament certification have been completed, which means no changes. I like the feel of these boats and can't imagine a better wake- I wouldn't want to practice with any better wake than I already have on my 03 RLXi because everything else is harder.

[doughickey]

To everyone that contributed to this thread.... my sincere thanks.

I just ordered the 13 X 12 from Skier to Skier.

The homework you folks did.... the posting of data..... the questions.... the answers.... the link to Skier-to-Skier..... helped me do my own homework, make the decision I felt roight for my application (based on your collective analysis), and pull out my credit card this afternoon!

I won't be putting the boat in the water until late May/early June (it snowed again today !!!).... but when I do, I'll post my performance data.

Thanks folks for the great help!

(THIS is why I love being part of this community!)

[mlange]

Hey Mark,

Did you do the Jan's Fans thing on Sunday? Sounds like the weather really sucked for it.

Mike

[andyb]

I'm curious that USA Water Ski have approved the Indmar Hammerhead 5.7 litre motor. In fact the Hammy is 383 cu.in. or 6.277 litres capacity. Have a look at http://www.sallee-chevrolet.com/ChevySmall...ZZ383-425P.html for the goss on this motor.

In my 2005 Response LX it is a totally different beast to my previous 335hp Monsoon in the 2003 Response.

I tried my spare 13 x 12 Acme on the new boat and found Perfect Pass speeds were around 3km/h slower (rpm based speeds) but wasn't game to try WOT as the Hammy hits the limiter with the 13 x 12.625 Acme.

I don't have a GPS check for accuracy and can only rely on set up with Perfect Pass and a properly surveyed slalom course. Top speed previously was indicated at 77km/h (47.8mph) - the new rig, taller prop and bigger lump shows 83km/h (51.6mph). Heading in the right direction because my ski club is wanting to include a skifly demo the next time we host the NZ Nationals and pro-skier Kyle Eade reckons he needs a pull through the air.

Should be interesting.

[martho]

Well,

Here is the scoop.

The OJ XMP turned 5160 and ran 47.8 at WOT with just me in the boat and 1/2 tank fuel. The wind was out of the E at 8, but I did N/S/E/W runs and they were all within .1 MPH.

I took 3 LL runs and the boat ran 44.5 with just M3Fan driving and WOT

I set the PP with no adjustments, just straight speed with a GPS.

32MPH is 3120RPM

30MPH is 2920RPM

The ACME 13x12 settings are higher than 100rpm =1mph.

The ACME may be a bit better on top end with a footer in tow as it is almost 2mph faster with a LL footer. The M-325 just doesn't have the horses to spin the OJ enough as the RPM's were way down with me LL.

My $0.02:

If you are using the boat for everything except footing, the the OJ XMP is the way to go as you turn less R's for the MPH. That has got to add some fuel efficiency, however I don't know if it is measurable and less turns of the engine may equal longer life of the engine. YMMV

The ACME will turn more RPM's and get you a bit more top end with my set up, however I think that is the only measurable difference.

For the average user who doesn't foot, I think either prop will work just fine.

[martho]

Hey Mark,

Did you do the Jan's Fans thing on Sunday?  Sounds like the weather really sucked for it.

Mike

<{POST_SNAPBACK}>

Yes,

I took 2 LL runs behind a PS209 which had 2.5hrs on it. I asked for 42mph and went from there. It was sleeting while I was footin. That was a first for me and for the group at Jan's Fans.

INFO

Another newspaper story[

Edited May 4, 2005 by martho

[mlange]

Well, finally got out today and actually remembered the GPS.

With a full tank of gas, I was running passes w/ the 13x11.5 at just a touch over 45mph @ 5000rpm at WOT - a bit disappointing since I like to foot half the time.

I still think the 13x11.5 would be THE prop for me if I just skied, but now I'm wishing I had gone with the 13x12.

Mike

[doughickey]

Well, finally got out today and actually remembered the GPS. 

With a full tank of gas, I was running passes w/ the 13x11.5 at just a touch over 45mph @ 5000rpm at WOT - a bit disappointing since I like to foot half the time.

I still think the 13x11.5 would be THE prop for me if I just skied, but now I'm wishing I had gone with the 13x12.

Mike

<{POST_SNAPBACK}>

Thanks for the new info Mike. I'm pretty anxious to get my prop and try things out. Still a few weeks away... but I'll let you know how I make out with the 13" X 12"

[doughickey]

Here's my OJ 13" X 11.5" results.

Somehow, the 11.5" arrived instead of the 12". Tried it anyway:

(Net is I am working to get it replaced with the 13" X 12").

MY BOAT: 1998 RLX; 310 carb; (posted redline by Indmar is 4800 rpm). Weight 2450 pounds. Main usage is skiing. No wedge. No fatsacks. Minimal boarding.

BEFORE: With the CVP 13" X 13" stainless

Good hole shot, good midrange. At 4800 redline I got 47 mph (GPS). Top speed 49 mph (GPS) at 5000 rpm.... just past my redline

AFTER: With the OJ XMP 13" X 11.5" Nibral

Great holeshot, great midrange. At 4800 redline I only get 43.4 mph (GPS). At 5000 rpm I get 45.4 mph, and have throttle left that I can't use. Would over rev the motor if I burried the throttle.

I'm not a strong enough or good enough skier to notice any difference in wake characteristics.

NET: I've got power left that I can't use.... and I'm revving higher (about 300 rpm) than I have to for any chosen speed. I lost about 4 mph. The 12" pitch will be a better choice.

Edited June 6, 2005 by doughickey

[martho]

I would not be surprised if the 12 is the perfect fit. My sportster turned 5300 with the 13x12 ACME (I know you are getting the XMP).

The 13x12 XMP just takes more engine to spin it as is slips less. I hope the 12 XMP works well for you. Please post your results.

[martho]

Played with an 04 RLXi M340 today and the GPS

These are full tank of gas and 2 people in the boat. This same boat turned 5200 RPM last week with the ACME, so the hot humid 90F air today may have had some effect on the numbers. Two weeks ago, WOT = 46.3

Acme 13x12

30mph = 3000rpm

35mph = 3500rpm

45.2 = 4800 RPM @ WOT

OJ 13x12 XMP

30mph = 2900rpm

35mph = 3400 rpm

44.8mph = 4800rpm @ WOT

There was a noticable hole shot difference with the XMP not having the get up and go that the Acme has. The XMP just bites the water and needs more engine to turn it.

After all of these tests/reviews, it is my opinion that the XMP is just too efficient for these boats. It is a great prop, maybe too good for the HP range which we have in the Malibus. It just seems that no one can spin the 13x12 to the limiter.

[doughickey]

To martho: Thanks for posting your performance results.

I spoke with Max (Skier-to-Skier) this am about returning my 11.5" and replacing with the 12". He's having one of his guys call me. Essentially, he's a bit puzzled with my results of the CVP (ie: 3200 rpm at 34 mph) vs the OJ XMP (ie: 3650 rpm at 34 mph).

As I explained, my motor (Indmar says my 310 carb has a redline of 4800) is able to spin the 11.5" pretty fast. Too fast. At 5000 rpm and 45.4 mph (past redline) I still have throttle left that I can't use.

Could be I have an extremely strong 310 carby. Maybe my tach is out of whack. Maybe my GPS is reading wrong. I think I just need the 12" pitch.

My guess (kinda validated by your results) is that the 12" pitch will get me to 34 mph at about 3400 rpm. Right where I'd like to be.

I'll let you know how it works out.... once I get it swapped (assuming I do) and run the 12" pitch.

Edited June 6, 2005 by doughickey

[Addictedto6]

There was a noticable hole shot difference with the XMP not having the get up and go that the Acme has.  The XMP just bites the water and needs more engine to turn it.

<{POST_SNAPBACK}>

Martho - just making sure I understand correctly. Which had the better hole shot?