imco lower on 25 checkmate
 

Has anyone tried a 2" Imco lower on a 25 Convincer
and is so what prop did you use. I don't know if I should
use a Hydromotive quad 4 or a Bravo 1. How did the
setup work? I have a Bravo XR now.

Re: imco lower on 25 checkmate
 

I have a standard length Imco lower on my 259 spinning a 24" Hydromotive P5-X. I would like to try a shorty lower but cant see investing that much $$$ for something that may not work. There is someone I know who is running a shorty lower on his B-Max, I am sure he will chime in here soon. There is one big difference, he is running real big power. :eek:

Re: imco lower on 25 checkmate
 

I'm running a Bmax 2" shorty and a maximus 5 blade prop. The results are great for me, but I wouldn't buy one based on my setup.

Question is- how many inches below the hull is your prop shaft? If it’s around 6" or more, trying a 2" shorty is a good idea. You may find adding a 1" spacer on the 2" shorty works out well. Unfortunately its all about testing, and that cost $$$. I’ve been at it 3 years with this hull and I'm still learning.

What prop, ratio, speed (gps) and rpm are you running now?

Re: imco lower on 25 checkmate
 

zt 260,
I have not installed the 2'' Imco yet. My old numbers as as follows--
28p bravo1 spinning 5950 rpm through a bravo XR drive with a 1.50
ratio. Gps speed is 88.9 mph. I would like to lower my rpm by
about 350 and would love to be in the low 90 's. I have access to
a one inch imco spacer and thats why I am tending to order a 2"
shorty for initial testing. I can't measure the prop shaft to hull dimensions
until the weekend but will contact you with the results. How did you decide on the Maximus vs. a p5x? What are you running rpm and pitch--I heard
you have big power.

Re: imco lower on 25 checkmate
 

I was running 6100rpm with 1.3 ratio and a 26' maximus. I just labbed the prop again, and I don't have any new WOT numbers yet. But it was running 103mph. I went with the maximus for the larger diameter. Right now the propshaft is only 3" below the hull, so its surface piercing for the most part. I could never get on plane with a bravo 1.

You are running prop slip about 12%. I would try a bravo 1 30" with the 2" shorty before I did anything. If you can still plane this could be the ticket, and it should lower your rpm by 200-400. If you can't plan try the 1" spacer.
What hp are you running? 750-800?

Re: imco lower on 25 checkmate
 

zt 260
I am running 810hp at 5800 on th dyno with 7.5 lbs of
boost on a 500 ci motor. Thanks for all you input. I will fill
you in after this weekend-----God knows I will never catch
you---104----very impressive--with more to come.