Bravo3 4 Blade Front Prop

[capav8r]

So, I snagged a set of B3 props on ebay for very cheap. They are the new design which is a four blade on the front and the usual 3 blade on the back. The pitch is 1 higher than my current 3x3 setup. According to Mercury's prop selector, this would be the correct pitch with the new design, 4 blade set. Here's the question: What improvements will the 4 blade make??

[seapuppy]

probably more thrust which allows you to get up on plane faster.....little better effeciency on the top end.....





SP

[oldno7]

Found this:

In 1999, while still employed at Mercury Racing, we began development of a new set of B3 propellers. The reason we did this was Formula began mating 500 EFI engines to B3 drives on their sport cruisers. The second generation B3 props (still a 3/3 set up) was cavitation burning so fast we couldn't get 10 hours on the props before their would be a hole in the front prop blades. The new development produced 2 finalists. One set had a 4 blade front which truth be told was a mis communication accident. However, after much testing it was determined the 4/3 had the better cav. burn resistance and the performance was equally as good as the other new development set. What we found was the 3/3 original set was slightly faster still. However, the new 4/3 burned much less and had a slightly better mid range. We decided to release them under the Mercury Racing logo and it took till 2004-2005 to get it done. This is the time frame slightly after my leaving Mercury Racing. The decision to Hi Polish the props came from the management that took my place. Hi Polish looks pretty but isn't a performance related issue.

If a guy wants low end and mid range specifically, the 4/3 is the better choice. If bow lift and speed are the main concern, working the 3/3 is still the better choice. Unfortunately, I believe the 3/3 is going to go away for good.

Now, as far as the new 4/3 versus the Merc Racing 4/3, there doesn't appear to be much difference other than the finish and a bit of a geometry and cup change. Main line propellers has basically created a new propeller option to continue moving forward with new offerings in the market place. It has a duller finish and is priced to offer the consumer a option. And a Hi Polish price point to match the Racing XR version. The whole thing is kind of goofy in that main line has created a product to directly compete with the Racing product.

We have worked with the XR propellers here at BBLADES. We have yet to work with the main line 4/3.

Again, bottom line, 4/3 for low end, 3/3 for top end. Also, go down 1" of pitch if you go from the 3/3 to the 4/3.

[shrew]

^^^^^^^ References/Links Please.

[oldno7]

Shrew

Came from here:


http://midwestboatparty.com/forum/ar...p/t-20568.html

[capav8r]

Launched the boat yesterday with the 4x3 propset. WOW!! It comes on plane much quicker AND I am showing 2~3 higher mph. Another positive, in another thread I had asked about a vibration when the drive was trimmed up much at all. That vibration/noise is gone with the new propset. I am guessing the 3x3 props were cavitating? Here is a really odd thing: The set I had (which was the factory setup) is a 20p. This new set is a 22 1/2p. I am still hitting right at if not slightly over 5k rpm's. Apparently I was under propped with the factory supplied props.... Anyway, I think I have found the right props for my boat!!

[ss3964spd]

[rcswando]

Anyway, I think I have found the right props for my boat!!

What boat do you have Cap?

[capav8r]

It is an '06 2600SE, 350 Mag/MPI

[iceman]

Cap:
You may remember we have the same boat, although my engine is a 5.0L MPI. The performance improvement is great news, and looks like something I need to consider. I never would have thought of even looking at Ebay for props. Were the props new or used? Would you mind passing along the price you paid?

Also, when you say you're showing 2-3 higher mph, are you talking about top speed? Or do you mean fuel efficiency (gph)?

Great to hear your boat is performing so well and you're back on the water!

Tom