1.25 Ratio or 1.5
 

Back in 2005 I put a nice well built 540 into my 2001 Velocity 260. Nothing major motor wise. Mild cam, 9:0 comp. Dyno right @ 620 hp.. Running good for 5+ summers now. Only issue has been with idle in gear. Livable. but not as "good" as one would hope. Nickerson has worked on the carb several times. Motor runs great.

So.. fast forward to 2009.. Got some good size flakes in the drive oil the drive oil when changed close to end of summer.. Decided to live with it and take a look this winter. Just opened the drive today.. Seems as if I took out a lower gear. Almost an entire tooth missing. explains the flakes right? So.. upon further inspection seems as if I have been running a 1.25 ratio drive. NOT a 1.5.. guess that also explains the problem of never being able to spin the prop past 5K (more or less).. got a 5 blade hydro on it.. I just thought i was over propped even though my motor "should" spin that prop OK on that hull..

Question.. What should I do? go with 1.25 ration again? 1.36? or 1.5? could the 1.25 ratio be an issue at idle? too much load on the motor when shifted into gear? Will I need to go bigger on prop if I switch to a standard 1.5 lower gear set? What is the appropriate setup for this motor and hull? XR drive if that means anything..

thanks
John

Being a single engine I would go with the 1.5 gears. Then I would get rid of the 5 blade ( you never mentioned the pitch) and go to either a 25P 4 blade or 27P 3 blade. If RPM's go over 5800 at WOT then I would go up 1 size at a time on the pitch . Just curious what pitch is that 5 blade? Combination of the high gear and 5 blades is probably responsible for your idle issue and low WOT rpm's. That motor should spin at least 5600 rpm.

with your boat&horsepower,i would go with1.50.i have a 27 pitch 3 blade you can try.:coolcowboy:

Agreed, you don't need gears taller than 1.5 until you are running triple digits.

1.36 or 1.5. You may be able to still run your same prop with a 1.36 and just spin it about 400rpms faster.

My current prop is a 26 inch Hydro P5.. Lab work done by Mike at Hall's propeller..

How much RPM will I pick up going from 1.25 to a 1.5 ratio?? Right now I can spin the prop about 5k or so.. Also will my in gear idle quality be a bit better with the 1.5? How about coming out of the hole?

Can't say just how many rpm you will pick up but it definitely will be going in the up direction. Also it will idle around better and come out of the hole better. You can try it with the 5 blade, you don't have nothing to loose. If your still not happy and not seeing mid 5k's on the tach you can go to less blades and more pitch. Rule of thumb for every blade you add you should drop one size in pitch. If your having a hard time coming out of the hole than that much power and a 5 blade is really going to be hard on your drive. I would definitely go to the 1.5 gears and from there you will need to do a little prop tweaking.

Thanks pick.. Seems 1.5 is what most drives are.. Untill you run out of prop pitch is what I hear.. That is not going to be the case with me.. I have plenty of $$ invested into the p5, so I would like to make that work.. Ran great last year.. just ran into a wall at 5k.. I would think a switch from 1.25 to 1.5 would get me about 600 RPMS.. the in gear idle and the hole shot are a bit more important then every last RPM and top speed

1.25 to a 1.5 and you will definately need more prop pitch. I would guess 1000rpms difference or more. I think 1.36 to 1.5 is usually about 600 rpms.

ouch.. 1000... that is going to make the $2k invested into this prop a bad decision.. Guess I could always sell the 26 p5 on here??