bor

iTrader: (1)

Any body can tell me where to find the end ratio of a xr 1:50 and swap the lower for a 1:36 ?

thx

rbtnt

Here's a link to a chart.

http://www.mtboats.com/outdrivegearratios.html

bor

iTrader: (1)

that makes everything clear ,

thank you

speedreeder

I don't have my drink on........Can someone tell me which tooth count is a 1.35 lower? I am looking at doing this change also. THANKS

Mr Gadgets

The 1.346 ratio lower gears would be 15/17 teeth. if used with the XR 16/19 upper gears.

With the 27/32 B1 uppers, the ratio would end up being 1.343.

speedreeder

Mr. Gaget, What are the advantages/ disadvantages to running the 1.34 lower with a standard 1.50 B1 upper? I'm not putting any big H.P. through them(500). Also what is your thought on a sportmaster lower, as far as strength over an Imco. I think from reading a few articles that the upper will be weaker?! Thanks, Rob

bajabob

can you put a 150 lower on a 136 upper??? and can you put a 136lower on a 150 upper is this possable????

Mr Gadgets

Rob,
I dont see an advantage to going to the 1.34 lower when running lower hp. You would end up with smaller pitched props but it is usually a disadvantage. The lower gears are more costly when using 15/17 lower gears. Most common run is the 1.5 ratio untill you run out of prop.. Used to be the 34 pitch and above were not great, but I dont believe that is the case these days. But with low power you shouldnt even get close to those big pitch props..

Bajabob,
you can put any gears you want in the B1 if you try hard enough. The end result:
1.50 lower (15/19) with the 1.36 upper (27/29) will give you an overall 1.36 ratio.
1.50 upper (27/32) with the 1.36 lower (15/17) will give you 1.343 ratio. So you can't actually call the (15/17) lower gear set, the 1.36 lower..
Hope that makes sense.

Dick

bor

iTrader: (1)

I am building a litlle 21ft v hull normally whit eagbeaters on them but I put in a ls 2 all alluminium corvette engine in it whit estimaded power of 550hp .

I prefer a smaller prop because of the very light weight of the boat (2000 lbs ) so it doesn,t effect the handling to much

and the shorty is to keep the engine as low as possible .

bajabob

thanks dick i have a spare lower for my bravo . it a 150 . i now have a 136drive on my baja now i am runnig in the low 80mph with a 23mirage prop