2018+ XStar prop thread.

[FourFourty]

Figured I'd start a thread for those interested in changing from the stock prop size on the XStar.

I didn't spend as much time, as I should have, collecting data on my swap. I have a few data points though, and I am happy with the switch.

Stock prop with the 6.2 was an 18x16 OJ. I switched to a 18x17.5 (#3289) ACME prop. This is what I observed-

- Top speed was 35 on the stock prop, it is 41 on the #3289.
- Surf rpm was 3350 on the stock prop at 11.0. Its 3100rpm on the #3289
- No problem getting to wakeboard speed with stock ballast full plus 1100 bag on center floor. I'd say (educated guess), that it would handle stock+ 2-3k of ballast and people, before you'd need to drop back down in prop pitch. Who knows though, autolaunch is a wonderful feature, and I was only using single tab....
- I didn't get any GPH data, but I can tell you that a couple hundred rpm drop at surf speeds will typically reduce consumption dramatically. I did a long term measurement on my G, on a similar prop change. The new prop dropped surf rpm from 3300 down to 3000, and that dropped fuel consumption from 9gph down to 6.5gph (both measured over an entire season and 150ish hours each).

In past experience, I had seen cleaner surf waves on several different boats with an ACME prop (no idea why). I saw no change on this boat at all. I also surfed both sides before and after the switch. No change, except that the boat is a little quieter on the ACME because of the increased pitch, and lower RPM.

I'd have no issue with trying an equivalent prop from OJ on this boat...... And Eric is awesome to work with, if any of you want to try a different prop, and haven't worked with him in the past.

I should have GPH data on this new prop before too long. This time of year is a good time to get an accurate reading. The boat only goes out to tow this time of year.

[Mastercraftdave]

Great write up, its crazy that they are now using that size prop.

When you had your X23 did you ever find a prop that would accomplish this same goal? I would like to lower surf RPMs but not lose any top end. I was told this would be hard to do. Any thoughts?

[FourFourty]

Great write up, its crazy that they are now using that size prop.

When you had your X23 did you ever find a prop that would accomplish this same goal? I would like to lower surf RPMs but not lose any top end. I was told this would be hard to do. Any thoughts?

I had a 7.4 in my X23, so it was a different gearbox and prop diameter than you have.....

Being as you have a 2:1 gearbox, I'd think you could easily accomplish what you are looking for. You might not be able to make a huge change, without effecting the ability to easily get on plane when loaded.

I actually went up on diameter on my X23 (from a 14.5" to a 16"), and went down on pitch a little. Larger diameter makes a huge difference on prop slip at surf speeds. I'm not sure if you can fit larger than 16" on an X23, and still have enough prop clearance on the hull. You would have to measure it.

What is your stock prop size?

[wallnut21]

I believe stock prop on '18 X23 is 16.5x19

[XC500mod]

Stock prop on ‘18 x23 is 16.5 x 19.5.

I’ve got two Acme props coming I am going try out. 16.5 x 17 3/4 .120 cup and a 16.5 x 19 .065 cup. But this is a different topic for a different thread.

[Mastercraftdave]

Stock prop on ‘18 x23 is 16.5 x 19.5.

I’ve got two Acme props coming I am going try out. 16.5 x 17 3/4 .120 cup and a 16.5 x 19 .065 cup. But this is a different topic for a different thread.

I will wait for your findings. thanks.

[Mastercraftdave]

I had a 7.4 in my X23, so it was a different gearbox and prop diameter than you have.....

Being as you have a 2:1 gearbox, I'd think you could easily accomplish what you are looking for. You might not be able to make a huge change, without effecting the ability to easily get on plane when loaded.

I actually went up on diameter on my X23 (from a 14.5" to a 16"), and went down on pitch a little. Larger diameter makes a huge difference on prop slip at surf speeds. I'm not sure if you can fit larger than 16" on an X23, and still have enough prop clearance on the hull. You would have to measure it.

What is your stock prop size?

The stock prop size for the X23 with 6.2L I think is a 16 or 16.5. I would have to double check this. I may have to look at acme based on the results here.

[FourFourty]

The stock prop size for the X23 with 6.2L I think is a 16 or 16.5. I would have to double check this. I may have to look at acme based on the results here.

I'd measure the boat and see if you could do a 17". If so, I'd try a 17x18 with .120 cup.

Nice thing about OJ and ACME, is they will let you try several props till you are happy.

[XC500mod]

The 16.5 on the x23 on has just over 3/4” of clearance. Jim thought this was too little to make a 17 work.

[dvsone79]

Nvm...

[FourFourty]

The 16.5 on the x23 on has just over 3/4” of clearance. Jim thought this was too little to make a 17 work.

Agreed, going up to a 17 would only provide 1/2" clearance if that is the case. You'd probably start pulling gel off from cavitation.

[Fbeltrao]

For the Xstar 2018 with the 7000 - do you happen to know what is the stock prop and any guess which would fit better to low the rpms?
Many tks!

[EJ OJPROP]

Figured I'd start a thread for those interested in changing from the stock prop size on the XStar.

I didn't spend as much time, as I should have, collecting data on my swap. I have a few data points though, and I am happy with the switch.

Stock prop with the 6.2 was an 18x16 OJ. I switched to a 18x17.5 (#3289) ACME prop. This is what I observed-

- Top speed was 35 on the stock prop, it is 41 on the #3289.
- Surf rpm was 3350 on the stock prop at 11.0. Its 3100rpm on the #3289
- No problem getting to wakeboard speed with stock ballast full plus 1100 bag on center floor. I'd say (educated guess), that it would handle stock+ 2-3k of ballast and people, before you'd need to drop back down in prop pitch. Who knows though, autolaunch is a wonderful feature, and I was only using single tab....
- I didn't get any GPH data, but I can tell you that a couple hundred rpm drop at surf speeds will typically reduce consumption dramatically. I did a long term measurement on my G, on a similar prop change. The new prop dropped surf rpm from 3300 down to 3000, and that dropped fuel consumption from 9gph down to 6.5gph (both measured over an entire season and 150ish hours each).

In past experience, I had seen cleaner surf waves on several different boats with an ACME prop (no idea why). I saw no change on this boat at all. I also surfed both sides before and after the switch. No change, except that the boat is a little quieter on the ACME because of the increased pitch, and lower RPM.

I'd have no issue with trying an equivalent prop from OJ on this boat...... And Eric is awesome to work with, if any of you want to try a different prop, and haven't worked with him in the past.

I should have GPH data on this new prop before too long. This time of year is a good time to get an accurate reading. The boat only goes out to tow this time of year.

The 18 X 16 is for extreme ballast loads (Pro X-Star) which explains higher RPM and less MPH than the 17.5P. We have a 18 X 17 -#799-MF that would lower the RPM as well.

[chieb]

440 are you happy with the 18x17.5? Should I assume that is as aggressive as we could go on xStar with 6.2 I’d like to drop surf rpms a hair more then you are seeing if possible. Since the 3289 doesn’t show up on ACME website, I am wondering if there are others like 18x17.75 or 18x18 that i should try.

No lack of power for me, had a full 16 people on the boat on the weekend.

I welcome your thoughts. Thanks.

[Dan2060]

Figured I'd start a thread for those interested in changing from the stock prop size on the XStar.

I didn't spend as much time, as I should have, collecting data on my swap. I have a few data points though, and I am happy with the switch.

Stock prop with the 6.2 was an 18x16 OJ. I switched to a 18x17.5 (#3289) ACME prop. This is what I observed-

- Top speed was 35 on the stock prop, it is 41 on the #3289.
- Surf rpm was 3350 on the stock prop at 11.0. Its 3100rpm on the #3289
- No problem getting to wakeboard speed with stock ballast full plus 1100 bag on center floor. I'd say (educated guess), that it would handle stock+ 2-3k of ballast and people, before you'd need to drop back down in prop pitch. Who knows though, autolaunch is a wonderful feature, and I was only using single tab....
- I didn't get any GPH data, but I can tell you that a couple hundred rpm drop at surf speeds will typically reduce consumption dramatically. I did a long term measurement on my G, on a similar prop change. The new prop dropped surf rpm from 3300 down to 3000, and that dropped fuel consumption from 9gph down to 6.5gph (both measured over an entire season and 150ish hours each).

In past experience, I had seen cleaner surf waves on several different boats with an ACME prop (no idea why). I saw no change on this boat at all. I also surfed both sides before and after the switch. No change, except that the boat is a little quieter on the ACME because of the increased pitch, and lower RPM.

I'd have no issue with trying an equivalent prop from OJ on this boat...... And Eric is awesome to work with, if any of you want to try a different prop, and haven't worked with him in the past.

I should have GPH data on this new prop before too long. This time of year is a good time to get an accurate reading. The boat only goes out to tow this time of year.

I'm looking at the same thing. I have the 7000 and am at 4000 feet. Considering going from oj 18x16 to the 18x17. Hate to spend that kind of money for 200 or 300 rpm and it doesn't save on fuel. The new star with this big engine sure gets thirsty.



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