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marty5
03-10-2008, 06:26 PM
O.K. I know nothing about this stuff, but I have asked a general question on what prop to put on an '07 MCX X-Star, and I was curious if there are virtually unlimited options or there are just a few. My boat is coming with a 14.25 x 14.5(or 14.0)...is there really a difference between the two? Does the "cup" make a difference? Thanks for your help!

erkoehler
03-10-2008, 06:30 PM
Yes, cup/size will make a difference. How much ballast are you running?

Jerseydave
03-10-2008, 08:14 PM
OJ makes (at least) 2 choices:

#472 14.25 X 14
#473 14.25 X 14.5

I'll be running the 14.25 X 14.5 on my '05 MCX X-star this year. I believe the newer X-star comes stock with a 14.25 X 14. Look at the stamped numbers on your prop when you get it.

I'll post some performance numbers when I get in the water in about 4-5 weeks from now. I'll be running stock ballast plus about 1500 lbs.

erkoehler
03-10-2008, 08:19 PM
Where are you running the extra weight?

Jerseydave
03-11-2008, 02:49 AM
(2) 400 lb. sacs in rear lockers
600 lbs. lead under front seats. (approx.)

This is what I'm going to start with, boat still in storage for about 4 more weeks.

Question: should I fill the (2) rear on-board tanks too or leave them empty? MYMC says filling them may make the wake more "rounded" because their location is not that far back.

EJ OJPROP
03-11-2008, 06:31 AM
We now offer another size for the MCX and 6.0 motor, 14.75 X 15.5 LC XMP EDGE 4-Blade part # 522. This propeller has replaced the 14.25 X 14.5 as standard from the factory. We also now offer a 14.75 X 17.5 LC XMP EDGE 4-Blade for the 8.1 set ups. We still have the 14.25 X 14 and 14.25 X 14.5 in production as well.

CottagerGreg
03-11-2008, 12:32 PM
Interesting information.

So for all 2008 X-star boats with the MCX and 6.0 motors come with the 14.75 X 15.5 LC XMP EDGE 4-Blade part # 522

How is this prop with extra wieght in the boat? Pros or cons in comparision to the 14.25 x 14 prop?

EJ OJPROP
03-11-2008, 12:38 PM
Correct, the 522 is now standard. The addition of extra ballast, depending on how much, may require propping down to the 14.25 X 14.5 or for extreme extra ballast the 14.25 X 14. The 522 runs very well even with some additional ballast.

CottagerGreg
03-11-2008, 12:56 PM
My plan is to have the fly-high system (2500 lbs) and at most 5-6 people in the boat... would this suffice? I don't necessarily need it to Snap out of the water... I will have the MCX

rrbooker
03-11-2008, 01:01 PM
Go with the 14.25x14 with the mcx and the fly high system!

EJ OJPROP
03-11-2008, 01:04 PM
I would suggest running the boat with the 14.75 X 15.5 and see how it works with all you plan to put in it. If you find you need better low end then you could look at a reduction in pitch.

Ole Miss Rebels
03-11-2008, 01:42 PM
We now offer another size for the MCX and 6.0 motor, 14.75 X 15.5 LC XMP EDGE 4-Blade part # 522. This propeller has replaced the 14.25 X 14.5 as standard from the factory. We also now offer a 14.75 X 17.5 LC XMP EDGE 4-Blade for the 8.1 set ups. We still have the 14.25 X 14 and 14.25 X 14.5 in production as well.


eric ,
i thought the 14.75 x 15.5 was for an L18 xstar. now i read that the 14.75 X 17.5 is correct prop. 50% of the time we will use only stock ballast but then the other 50% we will be heavily ballasted (4000 total pounds). also, factor in fuel consumption. which of the two would you use for this application?

EJ OJPROP
03-11-2008, 01:51 PM
The 14.75 x 15.5 will work well with the extra ballast, better than the 17.5. Hard to say which way to go if you split the time with the ballast, the 15.5 will work better with the extra load than the 17.5 but should rev higher with the lighter load than the 17.5. Depends on which hair you want to split.

Ole Miss Rebels
03-11-2008, 03:41 PM
The 14.75 x 15.5 will work well with the extra ballast, better than the 17.5. Hard to say which way to go if you split the time with the ballast, the 15.5 will work better with the extra load than the 17.5 but should rev higher with the lighter load than the 17.5. Depends on which hair you want to split.


Eeric,

thanks for the reply. i think i understand what pitch does and how it affects the boat. i do not understand what diameter does nor do i understand the definition of cup or what it does. would you please give me a brief high school definition /description of what effect diameter has on the engine and boat and what the definition of cup is and what effect it has on the engine and propulsion of the boat. thanks. i just want to understand.

EJ OJPROP
03-11-2008, 04:08 PM
Pitch, diameter and cupping all work together. We can run lower pitch with larger diameter. The larger diameter loads the motor like it had more pitch. The lower pitch with the larger diameter allows for a stronger more aggressive low end.

Cupping essentially loads the motor as well, holding the water on the blade a bit longer. More cup equals less RPM. More cup can also help with low end power. Cup adds effective rake to the propeller. Cup also effectively adds overall pitch to the propeller. For example a propeller that is stamped 15.5, the overall pitch would be higher with cupping taken into account, as the stamped pitch is really a median of the entire prop without cup added. Keep in mind that not all propellers are pitched the same. One company may have a constant pitch propeller, pitch that is constant from lead edge to trail edge or they may have progressive pitch or even regressive pitch propellers. There are several ways to pitch a prop.

I see alot of guys get hung up on cupping too. Most of our propellers have a standadrd .090 cupping to .120. These number seem to work well with our pitch and rake distribution. More cup from .090 to .110, would lower the max RPM approx 200. Another thing to keep in mind is no two boats are alike. So performance of a propeller on your boat may vary if that same prop were to be run on a like boat.

Hope that answered some of your questions.

Ole Miss Rebels
03-11-2008, 04:25 PM
Pitch, diameter and cupping all work together. We can run lower pitch with larger diameter. The larger diameter loads the motor like it had more pitch. The lower pitch with the larger diameter allows for a stronger more aggressive low end.

Cupping essentially loads the motor as well, holding the water on the blade a bit longer. More cup equals less RPM. More cup can also help with low end power. Cup adds effective rake to the propeller. Cup also effectively adds overall pitch to the propeller. For example a propeller that is stamped 15.5, the overall pitch would be higher with cupping taken into account, as the stamped pitch is really a median of the entire prop without cup added. Keep in mind that not all propellers are pitched the same. One company may have a constant pitch propeller, pitch that is constant from lead edge to trail edge or they may have progressive pitch or even regressive pitch propellers. There are several ways to pitch a prop.

I see alot of guys get hung up on cupping too. Most of our propellers have a standadrd .090 cupping to .120. These number seem to work well with our pitch and rake distribution. More cup from .090 to .110, would lower the max RPM approx 200. Another thing to keep in mind is no two boats are alike. So performance of a propeller on your boat may vary if that same prop were to be run on a like boat.

Hope that answered some of your questions.


this is the first time i have seen it written clearly. thank you for your help here and always.

magnum
03-11-2008, 05:33 PM
Eric, I have test driven an 04 X-star 8.1L that had the original stainless steel prop and it felt very sluggish from the hole shot and less power than the MCX or LY6 engine . What kind of performance improvements will this new prop do for it . 14.75 X 17.5 LC XMP EDGE 4-Blade for the 8.1 set ups.

EJ OJPROP
03-12-2008, 06:05 AM
The 14.75 X 17.5 improved the low end without hurting the top end, providing better overall performance. The new propeller is worth a trial with the 8.1.

TMCNo1
03-12-2008, 06:44 AM
this is the first time i have seen it written clearly. thank you for your help here and always.


You don't see this type of interaction with owners from any of the other prop manufacturers and that says a bunch!
Thanks Eric, for being here for us!

Ole Miss Rebels
03-12-2008, 03:41 PM
You don't see this type of interaction with owners from any of the other prop manufacturers and that says a bunch!
Thanks Eric, for being here for us!


i concur wholeheartedly. EVEN IF someone had a slightly better product and/or at a slightly better price I would feel compelled to stay loyal to the oem supplier. they are the guys that MC uses and we owe it to them to try to keep them strong. i have had nothing but excellent results with oj. also, eric has gone above and beyond with answers, info, help and service. they are my prop company. no need to look elsewhere. thanks eric. i enjoy doing business with you.

EJ OJPROP
03-12-2008, 03:57 PM
Thank you for the support guys. It is very important to me to be involved here as you guys are the ones who count, the guys in the boats using the products. I do listen to all the comments, good and bad, and try to insure we provide the best overall products and service possible. I do not take anything for granted and work hard to insure you guys end up with the best we can offer. So keep the comments and suggestions coming, I'm listening.

Jerseydave
03-12-2008, 05:47 PM
Eric, I spoke with you about a prop for my '05 MCX X-star. I will do some testing with it in about 4 weeks and post my findings. I'll test both with ballast and without, using a stopwatch and record rpms vs. speed at different speeds as well as top speed/rpms.

1boarder
03-12-2008, 08:02 PM
Eric,

Since you brought up the 14.75 x 15.5 on a MCX, would this be better than the 14.25 x 14.5 that came on my X2 (MCX) running 2500 lbs of total ballast.

EJ OJPROP
03-13-2008, 06:41 AM
If the current 14.25 X 14.5 runs higher RPM than you prefer, then the 14.75 X 15.5 would be worth a try. I'll take it back if it does not provide the performance you are looking for.

CottagerGreg
05-07-2008, 11:21 PM
http://i89.photobucket.com/albums/k212/GTI2lo/2008%20Mastercraft%2040th%20Anniversary%20X-star/DSCN5456.jpg

On my new 40th Anniversary X-star

Power
05-07-2008, 11:48 PM
We now offer another size for the MCX and 6.0 motor, 14.75 X 15.5 LC XMP EDGE 4-Blade part # 522. This propeller has replaced the 14.25 X 14.5 as standard from the factory. We also now offer a 14.75 X 17.5 LC XMP EDGE 4-Blade for the 8.1 set ups. We still have the 14.25 X 14 and 14.25 X 14.5 in production as well.
Can you please give us the advantage/performance difference of the 14.5 x 15.5 over the 14.25 x 14.5 based on a LY6 engine.

vision
05-08-2008, 12:10 AM
Thanks Eric for such a clear description of the importance of prop characteristics.

In our boat (08 X-star with an MCX), ballast distribution has a significant affect on how hard the motor has to work. We run about 1500 lbs ballast and 4 people in the boat. No problems with the stock prop until we begin shifting about 70% of the weight to the back of the boat to get a tighter wake lip. Once we get about 1100 to 1200 lbs in the back, the motor has a tough time pulling up a rider.

So as Eric indicated, you probably need to find the ballast ratio and weight that gives you the wake shape and size you want with your boat, then decide whether you need to change your prop.

Blair
05-08-2008, 12:20 PM
eric... pm at ya

magnum
05-08-2008, 12:48 PM
Has anyone with an X-star tried the New 14.75 X 17.5 LC XMP EDGE 4-Blade with the 8.1 Engine, I am totally satisfied with the stock prop on mine, just wonder if anyone has tried it and seen improvements

WESSTAR
06-19-2008, 11:55 PM
Now that the summer season has started does anyone have numbers on which prop is more efficent (for an 06 MCX X-star). I would like to change my prop. Now the question is 14.75x15.5 or the 14.25x14. I run stock ballast with 4-6 people. I feel that my stock prop is very sluggish with any more than 4 people in the boat.

vision
06-20-2008, 12:34 AM
I have an 08 X-star MCX with 14.25 x 14 OJ prop and run about 1500 lbs ballast and 4 people. This prop works reasonable well although it is a little sluggish out of the hole. Gets just shy of 6 GPH in efficiency. Running at 3400 rpm to achieve 25 mph.

Eric at OJ Props just sent me a new 14.75 x 13 prop to try. I wil let you know how it performs.

Have to give a shout out to Eric at OJ props. Amazing customer service!

Ole Miss Rebels
06-20-2008, 02:01 PM
Now that the summer season has started does anyone have numbers on which prop is more efficent (for an 06 MCX X-star). I would like to change my prop. Now the question is 14.75x15.5 or the 14.25x14. I run stock ballast with 4-6 people. I feel that my stock prop is very sluggish with any more than 4 people in the boat.

wes, i had an 05 xstar with mcx. it came stock with 13.7 X 17.5. that prop was only good for stock ballast and maybe six people. then i got the 14.25 X 14 and it made a tremendous difference.

i traded my 05 xstar with mcx for an 08 xstar with L18. it came with 13.7 X 17.5. it again was overpropped if i had significant ballast beyond factory ballast. i then put on the 14.75 X 15.5 and it has made a tremendous difference in hole-shot, ability to handle extreme ballast, and allowing the perfect pass to lock in solidly.

so, i have used both props but on different engines. all i can say is that the 14.25 X 14 was the perfect prop for xstar with mcx and the 14.75 X 15.5 seems to be the perfect prop for xstar with L18. good luck and let us know what you end up doing and how it works. whatever you do i would base it on what eric at oj suggests.

WESSTAR
06-20-2008, 04:47 PM
OMR thanks for the input I am going to buy a 14.25 x 14 today.

magnum
06-20-2008, 05:38 PM
Has anyone tried the New Prop that Oj's is talking about for the 8.1 L 14.75 X 17.5 LC XMP EDGE 4-Blade for the 8.1 . On an X-star Just wonder what difference it makes

Jerseydave
06-20-2008, 07:28 PM
Wesstar,

I have my '05 X-star with MCX running the OJ 14.25 X 14.5 prop.
I run approx. 2200 lbs. total ballast with 5-6 passengers.

Holeshot is great, no problems getting on plane in a respectable time/distance. Holds (wakeboard) speed very well, approx. 3600 rpm at 22 mph. (I will double check this tomorrow)

Top speed without ballast is approx. 39-40 mph. I barefoot on occasion, so the top speed is necessary for me. Otherwise the 14.25 X 14 would serve well. If you aren't concerned with top speed, you should be good with the prop you picked. Let us know your findings.

WESSTAR
06-20-2008, 09:27 PM
When I got to the shop they had a OJ 14.25x14.5 so I bought that instead. Next question is are there any tricks to tighten and loosen the nut? I am heading out to the hardware store to get a bigger wrench cant find the right size.

Jerseydave
06-20-2008, 09:47 PM
If you get the correct size wrench, great. But you could use a large adjustable wrench.

Use a 2X4 between the rudder and prop to hold it still while turning the nut. When using a prop puller, leave the nut on the last few threads so when the prop comes loose the nut will catch it.

You're running less ballast than me, I think you'll like that prop.
I had stock ballast +800 lbs. and 9 people last week and it still pulled well.

WESSTAR
06-24-2008, 01:38 AM
The new prop worked great! It uses a lot less throttle to get out of the water. We averaged 6 gals per hour. Thanks NJ for the help.

Ole Miss Rebels
06-24-2008, 11:37 AM
Has anyone tried the New Prop that Oj's is talking about for the 8.1 L 14.75 X 17.5 LC XMP EDGE 4-Blade for the 8.1 . On an X-star Just wonder what difference it makes

according to eric at oj that is the standard prop for 8.1L xstars now. he told me that if i was going to heavily ballast my boat that i may be better satisfied with the 14.75 X 15.5. i do ballast my boat heavily periodically but not all of the time. however, i chose to get the lower-pitched (14.75 X 15.5) prop. i use it all of the time (heavilly ballasted and moderately ballasted) and it is the prop that i am going to keep on my 08 xstar with L18. couldn't be happier. good luck and let us know what you end up doing and how it works out for you.

Jerseydave
06-24-2008, 05:57 PM
The new prop worked great! It uses a lot less throttle to get out of the water. We averaged 6 gals per hour. Thanks NJ for the help.


No problem! Just for grins, check your rpm's at 22 mph and tell me where you're at (with full ballast) Some of my friends think that 3600-3700 rpm's is too high, but I think that's ok considering the 2200 lbs. I'm running.

I'll try mine next time out with just stock ballast and see what my rpm's are.

Ole Miss, how do you like your new '08? Bet that L-18 could pull a house into a lake! :D

WESSTAR
07-01-2008, 07:07 PM
NJ sorry it took me do long to get back there has been so much smoke in the air here we have not been able to go out. With stock ballast and 6 people at 23 mph it was about 3500 rpms. I forgot to look at 22 next time I will.

Ole Miss Rebels
07-02-2008, 12:30 AM
No problem! Just for grins, check your rpm's at 22 mph and tell me where you're at (with full ballast) Some of my friends think that 3600-3700 rpm's is too high, but I think that's ok considering the 2200 lbs. I'm running.

I'll try mine next time out with just stock ballast and see what my rpm's are.

Ole Miss, how do you like your new '08? Bet that L-18 could pull a house into a lake! :D

hey njskier,

i love my boat but i ordered it before the twin silentmaster muffler option was available. wow is it loud. the option was only a $350 adder but will be between $1500-$2000 to retrofit. i still may have to do it as the boat is so loud that it makes for a long day on the lake. i have a great stereo upgrade package in my boat but due to the engine noise i have to really crank it up and then i have a roaring engine AND stereo. ouch!!! otherwise, i do like my boat very much. the engine is overkill for an intermediate rider but coupled with the FlyHigh Pro X ballast system and correct prop you can sure generate a mean mountain of water and that is fun even if you're just doing simple jumps and surface tricks. thanks for asking. also, the Z5 rigid cargo bimini is really nice. it affords tremendous coverage and looks good on the boat to boot.

craig3972
07-02-2008, 01:25 AM
have you looked into an FAE (fresh air exhaust) kit? they are supposed to dramatically reduce noise

vision
07-02-2008, 08:12 AM
I second Craig3972's suggestion. I have a FAE on my 2008 X-star with MCX engine. No decrease in performance or gas mileage and wow what a reduction in noise!

The best stereo system upgrade I have ever purchased is the FAE!


have you looked into an FAE (fresh air exhaust) kit? they are supposed to dramatically reduce noise