Is there really much of a difference in terms of drive wear/chances of breakage when running a 34 pitch Bravo One versus a 30 pitch? Trying to determine whether a change in drive ratio is really worth it, if the only reason for the change is to run a prop. that's only 4 pitches smaller, and still pretty big at that. Thanks in advance for any help.

Typically we see gear reduction changes when one runs out of prop. What are your performance numbers and goals. This may help you to decide what is going to acheive those goals.

Julie

ttt

Julie, thanks for the reply. My performance numbers are fantastic with the two props I'm running now - a 30 pitch Bravo One and a labbed 29 pitch Mirage Plus. Slip is at 9 to 10% on my Checkmate. I'm wondering if I were to bump up the power such that I can run say 4 to 6 more inches of pitch (on the Bravo One prop), whether there is any reason to go to a lower gear ratio (ie better prop efficiency at lower pitch or substantially less wear on the drive), or just keep going with my current drive until I run out of prop. Top speed is the goal. Thanks again.

What are your current performance numbers?

WOT RPM?
WOT MPH?
Current Drive & Gear Ratio?

Julie

Julie, do you have a used non-labbed RH 36" Bravo laying around...already have a LH.

No, I am sorry but I do not. Are your running 36P propellers as your everyday propellers?

Julie

Your going to add how much HP? Looks like 600hp is in your future, and a 1.65 bravo will not hold up. Better get an XR and the highest ratio is 1.5 ratio. Email me I might be able to help you out.

Told you speed is addictive!!! :-)

When adding power it's not always about going up in pitch. Depending on the new motor you may run the same pitch as you did with the old motor but just turn the new motor to a higher rpm. It all depends on where the new motor develops HP and TQ. It's a very common mistake to add too much pitch when re-powering. This can cause all kinds of handling, speed and plane-off issues.

The best thing to do is to have the new motors dyno'ed. This will tell us exactly where the motors need to run for optimum performance.

There are many instances when a customer will actually drop pitch with new higher horsepower motors. For example; current power stock 454 300hp WOT at 4400 rpm (25 pitch prop at 62 mph), new power 550 HP @5800 rpm naturally aspirated (24 pitch prop at 78 mph). So going faster is not always about going up in pitch but getting the motor to operate at it's peak performance RPM.

Matt

No, just going to utilize them for a baseline on a couple of different boats. I realize they are a compromise at best, and 5's are probably the way to go.

Great post!