25p to 24p
 

can a 25 pitch mirage plus be "tweaked" to 24.i need 400 more rpms from this prop and wanted to lab and down pitch.can this be done?

The RPM increae is not a problem but there are many ways that that can be done including down-pitching. Post a little data and we'll take a look for you.

Julie

25ft active thunder,454 mag 365 hp,bravo 1 1.36 ratio.turning 23 mirage 5100 rpm at 67-68 mph.was thinking of switching to a 22 b1 also.i have this 25 mirage but can't pull the rpm

I bet if you change to a 1.5 gear you could spin that 25p and see 70mph.

is the gear ratio in the upper or lower housing?someone else said to change to a 1.50 said the top mph won't change but i will get there quicker

Upper

From what I have read a 1.5 ratio is better than 1.36 for most applications. The only reason to go to 1.36 is if you run out of prop pitch; like on a boat that goes more than 100mph.
A 1.5 ratio multiplies the engine torque higher than a 1.36.
Your boat will get on plan faster and will likely reach a higher top speed with a 1.5 ratio drive.

Are you sure on that? I believe its lower

It depends on the gear ratio.

To go from a 1.5 to a 1.36 the change is in the lower. To go from a 1.5 to a 1.65 the change is in the upper.

There are many various gear ratios that can be combined through the combination of upper and lower gears.

The 1.5:1 ratio would be the more popular with your particular rig. The low end grunt and throttle response would improve with the 1.5. Top end, with this HP range and pitch and speed window, I would say 6 of one and a 1/2 dozen the other.

That being said, let's work with what you have. Reworking the 25 Mirage Plus can be done to gain 200 rpm without changing pitch, diam. or effecting the efficiency. Your slip is too high to build more into the prop. 400 can also be gained but the speed throughout could be compromised.

I'd try a 23 Revolution 4 for overall performance.

What are the ultimate goals.

Pinion gear change'l do it.

Hey Awesome , don't mean to hijack:drink: ....but hey Brett did you get my prop??

btw spinning a hydro 25 on mine Awesome so far only could see 4900-5000 r's and upper 60's

OK, I don't know you OSO handle. I should but I can't remember.

Thanks

camp your's is a 25 4 blade right?i wonder how a 25 3 blade would work on yours.i can't pull the 25 but you have alittle more power than me.how's that thunder doin,any changes made?

brett we spoke at the end of last year.want to try your exchange program as soon as the ice comes off the lake 2-3 weeks.when i went from my 23 to the 25 i picked up cruise speed but lost top end.can i have both if you lab my 25?

Awesome,

NP, just let us know when you want to do the work.

Thanks

Yeah, it's a 4 blade cleaver style, was pretty banged up. Having Bblades put it back to origainal spec's then I 'll go from there. hopefully only thing is a gps plotter and getting the outdrive rebuilt. Marina ripped apart last week, needed some work in the upper., rather do it now than later. Was thinking of changing the colors but think I'll wait till next year. Try asking Gordo in the AT section he offered alot of advice to me when I was buying mine. He raced his 25 and tried alot of props. Good luck awesome........thinking of doing the a-bay run this year with another AT you should join us!