Erick11s

Hi, what happen if i change my bravo 3 ratio 2.2 to 1.81 ratio ?

With 2:20 now my Top speed is 47 mph with propeler ss 22 pich - 400hp- wot 4800-5200 - 4500 lbs cobalt 272. Deadrise 20

With 1.81 what will happen.?

Top speed ? What pich i will go?

That I want is good aceleration better top speed, no problem if i need to change my pich propellers.

Thanks in advance for your help

Erick

Griff

There is no reason to change the gear ratio. You will gain nothing.
The boat is never going fast. It was not designed to be fast.

Bawana

Wow Griff, way to kick a guy when hes down...LOL If you go to a lower ratio you will usually loose acceleration. Your at a good WOT rpm now as, Griff said you will gain nothing even with prop change. If you were changing because you blew your upper and got a deal on one with different ratio, you would have to change props to make up the difference.

Erick11s

Thanks fo yours comments but I forget to mention something important, my engine is 4800-5200 rpm, but at 3/4 throttle I get to 5000 rpm with a torque that is heard strongly and if I try to go to top end suspect that I it would dangerously 5200 rpm, I check the original catalogues of Cobalt and this boat. as offered with different engines 454 mpi 375 hp or 502 415 hp (my current engine has 400 hp) in both cases with bravo 3 ratio is 1.81 and with bravo 1= 1.50, I think that in the past of this boat they changed the transmission to 2.20 and I feel it would be very tied up.

Mr Maine

So you are over revving with current setup. Either going to 24 pitch prop set or a gear change is your option. A prop change is easier and I would think cheaper.

Griff

Boat test shows it as 52mph boat with a 496 mag which is 375hp at the prop and would be about 400hp at the crank.

You say top speed is 47mph, but then you said you are not at WOT???? and you are at 5000rpms. Its not going to hurt anything to push it to 5200rpms.

I would think you need to try 24" props also.

4bus

iTrader: (4)

If you are running 47 at 5000 with that set up don't change a thing, cause some how you got the slip down to 1 percent! Something is off with your numbers, slip should be well above 10 on that boat

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