Change Gears or Props???
#1
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Change Gears or Props???
Trying to figure out if it will be better to change gear ratio from 1.35 to 1.5 and go with a larger pitch prop. Or leave 1.35 and go with a smaller pitch prop.
I was seeing which one would be better for the engine conf and if slip numbers generally get better or worse with a lower or higher pitch.
Thanks
I was seeing which one would be better for the engine conf and if slip numbers generally get better or worse with a lower or higher pitch.
Thanks
#2
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Several very high power boat owners seem to favor either the 1.5 or 1.62 gears. I'm by no means on ya'lls level, but the gear ratio seems to be a better (if more expensive) option
#4
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A prop person on this site said a good starting point on props is twice the diameter of the prop is a good pitch to run. e.g. 15 5/8" prop w/32 pitch. My boat gets on plane way better with lesser pitched props but I have to run my 1.5:1 lower with a 35P because of coin. Hopefully next year I'll get some 1.36:1 lowers and 32P props for my birthday. I'd love the data comparison.
The only thing I ever hear is that the 1.5's are stronger.
Anyone else do this swap? What'd you gain/loose out of it?
The only thing I ever hear is that the 1.5's are stronger.
Anyone else do this swap? What'd you gain/loose out of it?
#6
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I would leave the 1.35's. I don't think you will see any big differences and you won't have to worry about running prop pitch.
A 1.35 change to a 1.5 is usually about a 3" pitch difference.
A 1.35 change to a 1.5 is usually about a 3" pitch difference.
#7
+1 especially with a cat. In my mind, 1.5:1 is standard gearing on a V and 1:3whatever is a good cat starting point. Unless your speeds are under 80 (guessing thats not the case with any skater...) I wouldn't entertain the 1:5 unless you have motors that really need to rev.
Last edited by tcelano; 07-19-2011 at 01:36 AM.
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Its on a 32 Skater. Ilmor V-10s. No6's. I changed cams in the engines again and they are making good power up top. The boat pulls like a freight train after about 85mph. Runs good to 120 but then feels like it hits a wall. I have 1.35's in the drive and am turining the props in. They are 16.5 x 35 Merc 4 Blade. Its only turning them 5500rpm @ 120. The cam change and valve train that i have will handle 6500. That is where i set the rev limiters. I just feel like if I change to the 1.5's like Peter at Skater suggested, and run the 35's i think it will get the engines up a little higher in there peak hp.
#10
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Here lies the problem. If you go to a 1.5 you will run out prop. The biggest four blade is a 34. You will need to go to five blade prop that the 32 Skater does not like. Been there done that. I did the gear changes on my 32 and I should have stayed with the 1.24. I have a set of 16.5 x 32 four blades I can sell you for $1500. MINT props. Way cheaper than gears changes.