1.36 vs 1.50 Bravo One
 

What are the major differences. I am looking at a 1.36 and am pretty sure 1.5 is stock. Someone set me straight please.

As a general rule I would recommend going with the 1.5 gear ratio until you run out of prop (about 35 pitch) and then go to the 1.36.

Matt

Ok, Why ? What are the advantages/ Disadvantages of the two. I see alot of 1.36 drives out there ? Can anyone explain the differances ?

Gear Ratio!

Theres as much argument over this as oil. My old formula sr311 ran faster with the 1.36 drives than the 1.5's. Some newer formulas are faster with higher ratios. It depends on the boat and the power and props etc. I have heard that the 1.36's will handle a bit more power too. Many moons ago, the most efficient prop pitch was around 25". For all I know, that no longer applies with the technology of the last 30 years.

"Gear Ratio", So PO you don't know ? Share your wisdom.

TTT How about some opinion's ??

I think "Wisdom" is a little strong; maybe dumb luck!

I have used Bravo XR's for several years now, but the only difference I remember between the 1:50 and 1:36 is the ratio. In fact I have changed ratios from 1:50 to 1:36 and back and all it takes is the upper gear sets.
Both are stock and both have many upgraded parts available aftermarket some of which I tried.

As far as I know the only difference is the Ratio!

I had a 26' cat with 800 hp and a XR drive. Stock ratio on the drive was 1.50, and the boat had a very tough time out of the hole because of a high X dimension. We were running a labbed 32 4 blade prop.

I switched to a 1.36 ration and was able to drop down to a 30" prop, which cured the issues out of the hole. The down side was a loss of mid range power. The 1.36 ratio was a little faster on the top, but not by much.

I would say stick with a 1.50's unless you have big power and start to get into issues with running huge props and or have problems getting on plane.

Our boat was more fun with the 1.50's, but not being able to get on plane because of prop blowout gave me no choice but to change to 1.36's.

XR's are 1:35 not 1:36 not that it matters:)

You can buy after market gear sets in a 1.36 ratio. At the time I bought mine the 1.35 was not available from Merc yet, so I purchased the after market set from Teague.

Thanks guys, PO you are right the only difference is the ratio, all other internals are the same, I am glad to hear the 1:36 can handle more power and may be better out of the hole, more top end is also a nice benefit:D It sounds like there is no real big deal between the two, from what I am seeing here 1:36 may be a better set up in the long run for reliability and future power increases. I wonder if there is a big difference in RPMs, and I would have thought you would lose top end with the smaller gear, I am glad to see I may be wrong.:D

Thanks Guys. I have a 251 Convinsor with a 572 cu. Its a new motor so I will see how things go. I also have a 12" Imco neutral box with a 2" shortie. I have both uppers 1.36 and 1.5 so I guess I'll have to try both. Getting ready to Dyno the motor Thursday, can't wait to start testing !!! :D :D :D

Re: 1.36 vs 1.50 Bravo One
 

Hey dlbcheckmate, How did you come out?

Re: 1.36 vs 1.50 Bravo One
 

I think Matt really nailed the answer. When you need a prop that gets in the mid 30's pitch to keep your engine RPM's where you want it at top speed, then it's time to consider the gear ratio change and lower prop pitch. Think about it guys; those blades will become sideways paddle wheels if you add too much pitch and then your prop efficiency will drop. Generally speaking, we don't need to worry about this unless we have something with a 1/1.5 ratio that is running in the 90's. --- JP

Re: 1.36 vs 1.50 Bravo One
 

I work with many clients who were ill advised to go with a 1.36 ratio because they ran out of prop pitch due to a poor set up on the boat.

Some boats run faster with a 1.36 than a 1.5 ratio. I wouldn't even consider the 1.36 ratio unless you have a top end speed in the 90's.

Some boats with the 496 HO have a higher top speed with the 1.65 ratio than the 1.5. These are typically boats that have a top speed of 70-80.

The best thing to do is to try all the different gear ratios with the proper prop pitch to find out what is the best set up. Of course that isn't practical for most of us. So make the best of what you have. If you have to go below a prop in the 22-24 range then you are limited with the selection of high performance props so it would be necessary to go with a lower (higher numerically) gear ratio. Keep the prop pitch in the high 20's to low 30's, that is the best and most efficient pitch range.

Matt

Re: 1.36 vs 1.50 Bravo One
 

Another factor to consider is prop speed. Smaller pitch turning faster is more efficient than a steeper pitch turning slower. RPM, X-dimension, stepped or unstepped, notch, pad are all differential's to consider. In my experience prop speed is the true factor of transmitting power to the water for high performance application's. Note all gladiator's come with 1:36. Bottom line spend some quality time during your dial in.