bravo ratio question

[stirling]

Does anybody know what the gear ratio will be if I :

use the upper XR from my current drive 1,50 :1 ,and the lower unit from a bravo 3 with 1,65 :1 ?

its just to try and see if I can get my propellor slip down,and get better speed.

what would be the first to break under load,the xr upper or the ,,normal bravo 3 lower ,in other words ,will the bravo 3 lower go broke faster than a xr upper will do under diesel power ?

sterling

[bajabob]

i can tell you what i did 2 same boats 136 drive 23 mirage prop the other 150 drive same prop 136 at 3000rpm 40 mph 150 at 3000rpm 36mphit took 3600pm to do 40 mph 136 boat top speed was faster iran 25 mirage with 150 drive 5000rpm 136 drive 23mirage was faster imagine that

[Westcoast]

Originally Posted by bajabob

i can tell you what i did 2 same boats 136 drive 23 mirage prop the other 150 drive same prop 136 at 3000rpm 40 mph 150 at 3000rpm 36mphit took 3600pm to do 40 mph 136 boat top speed was faster iran 25 mirage with 150 drive 5000rpm 136 drive 23mirage was faster imagine that

[JaayTeee]

Looking at the gear ratio charts in the manual:

XR uppers are 16/19

A 1.65:1 B3 uses a 27/32 upper
( the same as a 1.5 B1 )

The 16/19 XR and the 27/32 B3 figure out to be
the same reduction.

Being the upper reductions are the same,
you'll still end up with 1.65:1

[Griff]

Originally Posted by bajabob

i can tell you what i did 2 same boats 136 drive 23 mirage prop the other 150 drive same prop 136 at 3000rpm 40 mph 150 at 3000rpm 36mphit took 3600pm to do 40 mph 136 boat top speed was faster iran 25 mirage with 150 drive 5000rpm 136 drive 23mirage was faster imagine that

Could someone please translate this into the english language???????

[nwimbush]

Griff - I'll try.


This fellow has two identical boats, except one has a 1.36 ratio upper, the other 1.50

For the first test scenario, with a 23 Mirage prop, the following test reults were recorded:
@3000 RPM
1.36 drive - 40mph
1.50 drive - 36mph(It was also noted that the 1.50 drive required 3600RPM to reach 40mph)

The second test scenario's objective was to determine which boat had a higher top speed. It was evident, through qualitative data only, that the 1.36 drive/23 Mirage Prop combination had a higher top speed than the 1.50/25.

I'm not too sure of the origin of the dialect, but it does create a challenge!!

[tfarmer]

Thanks, Now I get it.

[bajabob]

nwimbush you said it better then me sorry about that guy i am new at this when i tested boat they were 24o sports both were 1988 year its just somthing to think about ??? i wanted to get good gas miles at cruise speed 55mph

[nwimbush]

Originally Posted by bajabob

nwimbush you said it better then me sorry about that guy i am new at this when i tested boat they were 24o sports both were 1988 year its just somthing to think about ??? i wanted to get good gas miles at cruise speed 55mph

No worries, Baja, we all appreciate your input and experiences and we're having some fun at the same time.