Bravo -1 29 vs 27?

[JCClark]

I have a Mercury 250 PRO XS 4 Stroke with a
Bravo 29-1 FS all plugs closed 5740 RPMs 77MPH

The Mercury upper RPM range should be 5600-6200 i believe.


What should I expect from a Bravo 27-1 FS
RPMS 6140?
Speed ?

[John Jackson]

I would expect 76 to 77 mph right on the limiter, and a much better holeshot and midrange. It will be a better overall prop, and a much better prop when the weather gets warmer. You didn't say what boat.

[21XDC]

If your motor makes more HP at 6100-6200 rpms than 5700, You should see more speed.... As well as better holeshot and acceleration. It it makes more HP at 5700, You might loose speed...

[John Jackson]

If your motor makes more HP at 6100-6200 roms than 5700, You should see more speed.... As well as better holeshot and acceleration. It it makes more HP at 5700, You might loose speed...

Mike, somewhat true as a guideline, with the main differences being in the props. But everything equal, max speed will always be slightly over the HP peak. The HP and torque curve multiplied by the mechanical advantage will determine speed. A 27" will have almost 8% more thrust at the same RPM. But close to the limiter, if you produce 4% less torque, you still have a 4% thrust gain and speed gain. His main speed limiter with a 27" will be the motor rev limiter. But as we all know, two exact props will run differently.

[21XDC]

Correct... So there is no correct accurate answer.... So I gave the best generic answer that is possible.

[John Jackson]

Correct... So there is no correct accurate answer.... So I gave the best generic answer that is possible.

Now go get a corona beer, should be cheap as sales have gone way down for fear of the corona virus.

[JCClark]

Thanks for the quick replies.
I guess it sounds like if everything is equal I should/could gain some speed at the higher rpms but that is if everything is equal.
In any case the 27 should just be a better all around prop choice. I will be trying it out soon.
The boat is a Ballistic 223

Thanks again.

[21XDC]

Post your results on this thread...

[Savage]

You will need the 27P when the weather gets warmer also. I would definitely sell the 29P.

[JCClark]

Installed the 27P Bravo ( all plugs in )
76 MPH 6100 +- RPMS full tank 2 people light gear. Hole shot is better.
Seems to be a better all around prop, just a hair slower, but it performs better in all other areas.

Thanks

[Savage]

Your motor sez THANK YOU!

[21XDC]

You might try removing 4 plugs and test holeshot again. Some 4 stroke set ups benefit.

[F-23 Stealth225]

Are you planning on selling the 29 bravo?