ratio problem ?????

[sampler]

Right now i have a old pre alpha that is a 160. with a gear ratio of 1.65. But the problem is that the gear are bad in it. So i found a Alpha one its a 1989 that has a ratio of 1.98 . what i really like to know is what is the pros and cons of this if i go from one ratio to a differnt? is it going to give me problems or can i just change the prop to a bigger size and bigger pitch? i have props one that is on the alpha is a 14x19 and the other one is 15x19. any help would be great . sorry so long

 

[180shabah]

Re: ratio problem ?????

You will be jumping two ratios, throwing your prop way off. Find a drive with the correct ratio in it. Have you looked at the SEI drives here at iboats?

 

[havasuboatman]

Re: ratio problem ?????

I agree, don't put that drive on.

 

[sampler]

Re: ratio problem ?????

I hear what you guys are saying but know really ansrwer if there could be any damage to my boat motor or any thing like that.

 

[achris]

Re: ratio problem ?????

You could put the drive on, but you will need to go to a 23 inch prop. That's quite big. You may have problems in the mid range of the engine as the ratio is now not matched to the engine torque band. If you put the drive on and change to the bigger prop, you won't damage your engine....

Chris.......

 

[jtybt]

Re: ratio problem ?????

As long as you keep to the WOT, you can use any drive ratio. Doesn't hurt anything.

I went from a 1.5:1 with 16X16 alpha to a 2.0:1 bravo with a 17 3/4 X 21 and wished I had the 2.20:1 gear ratio.

 

[sampler]

Re: ratio problem ?????

so should i go with a 15x 21 or 14.25 x23 what would be the best for me? boat is 23' fiberglass cuddy cabin . with a in-line 6.

 

[Lyle29464]

Re: ratio problem ?????

you changed 20% your new prop will need to be about 20% more pitch

 

[achris]

Re: ratio problem ?????

so should i go with a 15x 21 or 14.25 x23 what would be the best for me? boat is 23' fiberglass cuddy cabin . with a in-line 6.

If the old prop was 19", then just divide that by the old ratio and multiple by the new...

19/1.65*1.98=22.8 (that's close enough to 23) 21" will give you better 'hole shot' and easier cruising, but be careful not to over rev the engine....

Chris......

 

[sampler]

Re: ratio problem ?????

thanks to everyone for you help you guy are the best.