Nitro Z6 with 115 command thrust. Prop help?

[Nitroz6115]

First of all, this is my first post and any help would be truly appreciated. I recently put a Mercury 115 CT on my nitro z6. I was able to use the same prop that came off my optimax pro xs 2 stroke. (22P laser 2.) The prop on the new CT motor will get the boat on plane really quick but will hit the rev limiter around 45mph now. On the old motor, this prop was getting about 52 mph. On the old motor, I would trim all the way down to get on plane, then gradually raise the trim to get to about halfway on my trim gauge. With the CT, I trim all the way down to get on plane, but once I’m on plane I can’t even trim up to 1/4 of my trim gauge without the motor getting close to the rev limiter. Feel like I need a prop that will provide more balance. I love how quick I get on plane right now, but would like to get something that will get me to 50mph at least.

Can anyone that has a z6 or z17 with the 115CT on it tell me what prop you are running and your numbers? Can anyone give me advice on what prop I would need?

I hope this isn’t a silly question, and I am looking forward to your input. PS: I love everything about the CT!! Just feel like I need a different prop to provide the best production out of the motor.

Thanks!

[PatriotAW4]

You put a small hub 4.25" gearcase prop on a large hub 4.75" gear case motor and are wondering why it doesn't perform well? The Command Thrust has a lower gear ratio and also requires a large hub prop or you will get a ton of prop slip. You need a 23" pitch Tempest.

[Nitroz6115]

No, I didn’t put it on. The dealer did. Ha

I appreciate that on the 23” pitch tempest.

Would love to hear what those are running on their z17 or z6!

[Nitroz6115]

Can anyone tell me what prop comes factory installed on the z17 with 115CT motor?

[PatriotAW4]

They don't come factory with props, it depends on what the dealer installs.

[Nitroz6115]

I gotcha. That makes sense. Hopefully someone can chime in and tell me what works best with their z6 or z17. Are you pretty confident the tempest 23 is the right prop for my situation?

[PatriotAW4]

A 23" pitch Tempest turning a the 6300 max RPM for that motor with the normal 10% prop slip comes out to 51-52 MPH which is where it ran before correct? That is what I would try, you may loose a couple MPH by going from a 2 to a 4 stroke but should easily be able to get 50 out of it. Those motors are pretty powerful for just being a 115. Also since that motor has the larger gearcase and bigger hub prop you will likely have to run it higher than your previous motor to get the best performance out of it.

[Nitroz6115]

Thanks a lot for the response. That makes sense.

You say run it higher.. right now I can’t trim the motor up to 1/4 on the gauge without it coming close to the rev limiter. Will the 23p prop allow me to trim it up to half like I used too without hitting the rev limiter on plane?

[PatriotAW4]

Thanks a lot for the response. That makes sense.

You say run it higher.. right now I can’t trim the motor up to 1/4 on the gauge without it coming close to the rev limiter. Will the 23p prop allow me to trim it up to half like I used too without hitting the rev limiter on plane?

Yes, the prop you have now is not made for that motor so it has a ton of prop slip. Do you have a picture of what it looks like mounted on that motor? Its probably venting way too much as well since the hub is smaller than the gearcase.

[Chad2002xrd]

My 2024 nitro z17 with a 115 CT came with a 22p tempest. The service guy said that was the best fit....is he wrong?

My FIL had that exact setup and we could bang the rev limiter in the summer with a 22p Tempest. He never used the boat to its full potential and ended up selling it after letting it sit a while. I believe it could turn a 23p no problem.

[johnsobo]

Yours may differ a bit if it's a pro xs... in 2015 they did not have that motor yet so the rev limiters are different. If you have the pro XS you can go with a smaller pitched prop because your rev limiter is higher at 6300 RPM. This is my setup.2015 nitro z6 with a 115 command thrust. It came with a 25 pitch fury, top speed was 55. When loaded had a hard time getting on plane, I put a 24 pitch Fury with 1 medium plug installed on it and it worked out perfec, gets on plane fairly well and will run 52 miles an hour at 6100 RPM.

Also I can't remember what it's called but there is a white plastic shim that goes between the lower and the prop to keep the exhaust gases from escaping around the prop. Make sure you have that installed, my buddy refused to use it and went through 10 props trying to set his boat up and it still doesn't work well.

[AC-ANDY]

The props are installed by the factory before they ship to a dealer. On the newer Z17 models with a 115 CT, the factory recommends (and comes with) a 22p Tempest Plus with the engine mounted in the fourth hole. The factory also recommends running three solid plugs in the prop for best hole shot. What year is your boat? I can see if I can get more exact specs for your Z6. The last two years Nitro built the Z6 models (2015-16) they offered a 115 CT and ran a 25p Fury (sounds crazy, I know) on them. The engine was mounted 3" above the transom (probably around the 5th hole). I hope this helps.