Gear Ratio...1.36 or 1.50 ???? Which would be right for me?
 

Hello everyone!!

I have a Donzi 25 ZX. It has a pad bottom but no steps. I started a little project last year and have gone through the whole boat. New everything. I upgraded the 502 MAG to a 830 HP M-3 Procharged 502, Added a 12" IMCO extension box with a 3" rise, Changed the Bravo for a IMCO Xtreme SC with a IMCO 2 inch shorty and added IMCO dual ram hydraulic steering.

My question is this...the drive that I got has a 1.36 gear ratio. I keep hearing from the guys on the Donzi site (I know a lot of the same people are here also) that 1.50 is always better.


What do you think?? I am just starting to prop test and I have a Hydromotive 6 blade 29 pitch and a few other props that I have money tied up in but would rather not buy a bunch of props in the wrong pitch just to end up changing the gears later and have to change them out.


I have heard that the gear change from 1.36 to 1.50 is like 2 1/2 pitch sizes from some people and like 4 inches from others.

Tell me what you think!!! Help me out here!!

If you can turn a prop in the 30 pitch range, I think you have the right ratio in there now. Ratios are better expressed as percentage rather than a set number of inches. If you changed to a 1.5 ratio you would need a 33.33 inch prop to replace that 30 pitch.

I would stay with the 1.36's for your application. You could run out pitch options with a 1.50.

From my personal experience----keep the 1.36

I also would stay with the 1.36 ratio

Thanks guys...I just wanted to make sure...I have heard a lot of people saying that 1.50 is far superior to 1.36 and I just wanted to make sure that I am on the right track.

http://www.rbbi.com/folders/prop/propcalc.htm

I have always been told never to gear up until you run out of prop pitch. If you already have the gears/prop running @ the rite rpm it would not be worth the money.