|First off i have an 05' x star with an mcx engine. I'm not too sure what prop came with it but im looking to get more hole shot because it isn't exactly performing up to par with the boat loaded. Any help would be awesome|
|How do you have the boat weighted? |
|Most guys are ordering the 13.5 or 13 by 16.5 or 16. It depends upon how much ballast you typically run. I have put a 15.5 pitch on that boat for a very heavily weighted application. Factory plus 3,500 lbs.|
|factory ballast, 8 people or so and maybe 1500lb extra give or take.|
|845 13.5X16 - Most typical for your app |
977 13.25X15.5 - Rev limiter special, be careful
If you can trust the other drivers, the 977 would work well. It will get you out of the hole better and get the engine within it optimal torque range.
The 845 is a better all-around prop if you have others driving the boat a lot and occasionally go without ballast or want the cruising runs.
|thanks a lot Karl. I wasn't able to find the 977 prop on boarditup. what did you mean by rev limiter special?|
|I'll add it. |
Rev limiter special means that even with ballast you can hit the engine's rev limiter if you go to wide open throttle.
The reduced diameter grabs a little less water each revolution and the reduced pitch allows the engine to speed up more for the boat speed. The effect is that the engine runs faster (more rpm) and further into the torque curve.
|I have a 2006 X-Star with MCX and the Mastercraft "high altitude prop", I don't know the specs of that one. |
It improves things, but still not to a point that it is somewhat comfortable. I have the FlyHigh custom system for the X-star, 2100lbs and the X-Star needs that much weight to get a good wake. Problem is if I have to stand up behind the wheel for at least 30 seconds before the boat levels off enough to see out the front. And that is with only two people in the boat. We ended up moving those two people to the front to start and have them move to the back once on plane. As I said not comfortable.
The other problem is that I'm constantly running around 4200rpm at wakeboard speed, which does not make me feel comfortable for the engine.
I could reprop with the rev limiter special probably (I'm not hitting the limiter at all now), but then I presume I would be running at 4700rpm or so at wakeboard speed ?
|I'm also curious as to how changing the prop changes the engine life and driveability of the boat.|
|Hey Eddy, |
We had the same issue with a 2003 X-Star last summer. The boat was not leveling off for ages when coming out of the hole; we also had it loaded with similar weight and people.
We placed a 100 pound lead block in the very front of the boat (under the nose cushion) where the ice cooler is - it helped heaps, brought the nose down super quick and didnít impact our gas consumption at all.
Try it out and see if it helps with your issue.
|Typically, prop changes don't affect the life of the engine. In theory, it can, but the actual proof is hard to find. The main killer of engines is poor maintenance and lugging the engine. The right prop eliminates that problem. The rest is up to the pilot and the maintenance schedule. If you strain an engine with heavy ballast all the time, be very picky about your oil, oil filter, and oil change interval. Also, keep your intake very clean. |
Eddy - it sounds like you are simply out of engine for your application. 4,200 rpms at wakeboarding speed is a lot of revs. I think you have the rev limiter special on already. You may need the 8.1L motor for the amount of ballast your are running. Paul has a good point, it may be a boat trim issue. Start out without ballast and start running some tests. Have some moveable weight to work on boat trim. That may solve your situation rather than propping down in pitch again.
|That is the point I was trying to get accross; the X-Star, used as a hard-core wakeboard boat, NEEDS the big block. Especially if you are on a short setup lake, like we are (private ski-lake). |
As I said moving two people to the front improved, so I'm sure your trick could help. We have PVC pipes filled with lead and I will experiment with that.
with the new prop the boat drives like it did before. We are on a private lake with a very narrow turn and setup for the double-up and the prop did not make any difference.
Without ballast it jumps out of the water like a jetski now
|Just want to 'top-off' this thread for if someone researches it later. |
My X-Star weight-versus-engine problem was fixed with a new prop from ACME. Size; 14.5 x 14.25. The X-Star now accelerates comfortably and runs under 4000rpm at wakeboarding speed. This is with the MCX, standard ballast, 2300lbs extra ballast and 5 adults in the boat.
I developed our 14.25 X 14 and 14.25 x 14.5 OJ XMP EDGE 4-blades last year just for the situation you are experiencing. The larger diameter and lower pitch works better than the the standard reduction of diameter and pitch we have used over the years. This new propeller will perform better than any other "wakeboard" propeller out there or your money back.
Eric at OJ Props.