PDA

View Full Version : Top speed X2 with wakeboard prop?


Thrall
03-30-2010, 07:39 PM
Sooo, talk to Bill at Acme or Eric at OJ and they can't really give you a top speed for a given prop on a given boat, jsut a range of how much it may increase or decrease top speed, understandably.
So I'm looking for real world top speeds for the newer X2's, MCX with either an Acme 1285, 14.4x14.25, .105cup or the OJ #470, 472 or 473 ,14.25x14 or 14.25x14.5 various cups.
Talking smooth water, boat not loaded down, ideal, top speed conditions.
Don't have much basis for comparison as I can't even get rpms with the 13.7x17. I can get 4500-4600 rpms and about 38-39mph now.
Found that propping down my 190 to an Acme 543 13x11.5, I really didn't lose any top end. Ideal conditions, it would pull 44mph still.

And anyone who boats at high alt, over 6kft, would appreciate your opinions especially. Thanks.

venetrex
03-30-2010, 10:11 PM
my 2007 x2 with the 13.7x17 prop and mcx would pull 5100rpm and do approximately 39.9-40 mph. I bent it last year and now have a 14.25x14.5 OJ. Have not tested that yet. I also added a wakeplate this year. I'll bet that makes a change as well. I have a mcx and live in ct which is basically sea level

ttu
03-30-2010, 10:22 PM
well i don't have the mcx engine but my 310 rtp with the 14.25 by 14 will maybe hit 39 on a day with glass waters.

Thrall
03-31-2010, 10:05 AM
well i don't have the mcx engine but my 310 rtp with the 14.25 by 14 will maybe hit 39 on a day with glass waters.

So I'm lookin at maybe 40mph with the extra rpms of the MCX.
Looks like the 13.7x17 is a 40mph prop too, so that's what I'm looking for, really no top end loss with the lower pitch.
Funny, I could get between 38-39mph (on GPS) being 500-700rpms low, but a boat running out at full rpms like ventrex's only gets 40 mph. That last 500rpms is only good for 1-2mph?

ORX-1
03-31-2010, 07:17 PM
same prop 14.25 x 14 (pretty sure) and i can get low 40's on a good day

Thrall
04-01-2010, 09:03 AM
same prop 14.25 x 14 (pretty sure) and i can get low 40's on a good day

Cool! Wasn't sure if these boats could break 40mph or not with a MCX.
Just ordered an Acme 1285, 14.5x14.25, as reccomended by Bill @ Acme. If it makes the same difference as the 543 made on my 190, I'm set.
Was holding out for a used one since last yr, $500 is alot of $ for prop, but only was finding refurbs. Everyone must be happy with the 14 pitch screws they have.

jdl xstar
04-01-2010, 09:52 AM
My '07 X2 w/ MCX had an OJ 14.25x14.5 and it could hit upper 41 with no weight and good conditions. RPM right at 5200. It was a great prop with an excellent hole shot. I dont' rememebr other rpm with speeds but I know I was very satisfied with all aspects of the performance from wakesurf to barefoot. (I'm virtually at sea level)

EJ OJPROP
04-01-2010, 09:56 AM
For the over 6000 foot altitude a 14.25 X 14 may be a good choice

Loffgren
04-01-2010, 11:07 AM
41-42 mph 08 X2 MCX

Thrall
04-01-2010, 01:12 PM
For the over 6000 foot altitude a 14.25 X 14 may be a good choice

Yeah I was going to go lower, but that's what was reccomended by Bill. I only got the .105 cup, thought about the .150 cup. If I can't get full rpms out of it, I'm certain Bill will help with that.
Eric, you've been very helpful to me as well, thank you.
Just chose to go with the Acme based off of a real good experience with my 190 prop.

EJ OJPROP
04-01-2010, 01:15 PM
Just let me know when you want to experience the OJ

tr6coug
04-01-2010, 01:36 PM
My '07 X2 MCX will hit 42 - 43 on flat water with the 14.25x14 OJ. We hardly ever run WOT though.

I used to have the 13.7x17 and hole shot wasn't great and top speed was about the same. Switched to the 14.25x14. Huge difference. Boat practically leaps out of the water now.

Thrall
04-01-2010, 02:37 PM
Just let me know when you want to experience the OJ

You got it. You'll be the first guy I call if the 1285 doesn't fit the bill.

Question. What was the thinking behind the 13.7x17 as an OEM prop?
Was that OJ's reccomendation or MC's request?
As evidenced by the large # of people switching to lower pitched props and the abundance of 13.7x17's for sale cheap, surely there was a better option available for OEM applications 4 or 5 years ago.

Thrall
04-01-2010, 02:39 PM
FIWIW, Acme calculated that for my application, the 14.5x14.25 would raise my upper rpms 650+rpms over the 17 pitch I'm running, so that should put me right there.

EJ OJPROP
04-01-2010, 03:00 PM
The 13.7 X 17 is a very good prop and the correct prop for skiing and or cruising. It is not a very good prop for a boat that is heavily loaded. It will not be a very good prop at an elevation of 6,000 feet. Since not all the boats would be loaded heavily or running at an elevation of 6,000 feet the 13.7 X 17 was a good stock prop. We now run our 14.75 X 15.5 as stock, this prop works well with moderate ballast and maintains the MPH while unloaded.

The introduction of our EDGE wakeboard specific props, larger diameter lower pitch, allowed for the boats to be weighted like never before with an increase in performance. Prior to these sizes the typical "fix" to gain RPM and low end was to drop the pitch. The down side was the biggest gain was in just RPM as the lower pitch prop would slip more due to the lack of diameter.

What was the max RPM with the 17 fully loaded? A 650 RPM gain seems a bit much, calculated of course.

EJ OJPROP
04-01-2010, 03:03 PM
Sorry, I see it now 4500-4600. Part of the reason for the low RPM is the 6000-7000 feet. I doubt you will see 5250 with the new prop. I have a 14.75 X 13 that you will see 5200 with and see very good low end too.

MattsCraft
04-01-2010, 04:04 PM
I have the 14.75 x 15.5, prop works great for what we do. 1775lbs total balast and 4 to 6 people in the boat. Wakeboard, Surf and Free ski a few times a year. I think the prop performs well, never have anybody complain it takes to long to get on plane so I just ordered another one for backup.

I will say this, no way I can hit 42, best I have ever seen is 40, smooth water, down hill with a tail wind!:uglyhamme

Thrall
04-01-2010, 06:44 PM
Sorry, I see it now 4500-4600. Part of the reason for the low RPM is the 6000-7000 feet. I doubt you will see 5250 with the new prop. I have a 14.75 X 13 that you will see 5200 with and see very good low end too.

I know the 17 pitch would never be good at elevation. Just seemed to me that the X boats were designed for weight and wakeboarding, not skiing and alot of people at low elev are ditching the 17 pitch for lower pitch props.
Yeah, bringing the rpms back up THAT much does seem a bit ambitious, but propping down to a 13x11.5 CNC prop from the stock 13x13 on my 190 netted me about 500 rpms at altitude. I was running 4500rpms +/- with the 13x13 and got it to peg back at 5k rpms.
We'll see. Hope he's right. If not I'll be looking to you for advice next time.