S4Hadi

what are the advantages vs. disadvantages?

It seems that most sport boats use the B1, but I do recall a test in a boating magazine testing identical boats with same 496 HO power and ended up with similar top speeds?

Do the B3's use a different drive ratio ie. 2.0 vs. 1.5 for the B1's?

Jamal

sterndrivespec

we tried a test on our dive boat,a 25 searay with a 7.4.we used a bravo 3 with 2.0 ratio and 26 props,and a brave 1 1.5 ratio with a 23 mirage.top speed was the same with both.the bravo three had a better cruise speed at 3000 rpm's,and was much easier to manuver around the dock.this boat had a top speed of 51 mph.i think on a faster boat the bravo 3 might lose some speed due to drag from it's size

cobra marty

Is the bravo 3 the duoprop? And does it use a left and right prop? And can/does it use the mirage and bravo props off the bravo1? Will the bravo3 lower bolt to a bravo 1 upper?

Clay Washington

You can get the Bravo 3 with 2.2:1, 2.0:1, and 1.81:1 ratios. I have owned both a Bravo 1 and a Bravo 3 on two 22-foot Crownline boats (Same hulls, different years). The Bravo 3 as just as fast as the Bravo 1 on top end (up to 75mph). However, the Bravo 3 has a much better hole-shot and can maintain plane at a slower speed.

The two biggest differences are prop slip and prop torque. The Bravo 3 will have less prop slip because there are six blades in the water instead of three or four. The counter-rotation helps to reduce the prop torque.

On a "family style" runabout with a single engine, you can't beat the Bravo 3.

Note - I have a Whipplecharged 502 powering my Bravo 3, and it works GREAT!

Clay Washington

Cobra...

Here are some pictures of my Crownline 225LPX with a Bravo 3.

The Bravo 3 has its own props. There are two counter-rotating props. You cannot use a Bravo 1 prop on a Bravo 3 outdrive.

It is my understanding that the Bravo 3 upper and the Bravo 1 upper are exactly the same. So, it should bolt on.

Because I have so much torque with my Whipple, I am thinking about getting an XR upper. It should fit the Bravo 3 lower with no problems.

Iggy

From what I remember reading is that both props are slightly different in pitch. Someting to do with the way the water/thrust comes off the forward prop.

cobra marty

Clay, Nice pictures. I like the nosecone on the B3. Did it make any noticable difference? Is the B3 lower case the same as a B1 but with different internals? And would the B3 internals fit in an IMCO lower unit? What pitch props do you run? You are unique and one of the few running the B3 in a boat with power.

S4Hadi

Clay,

Nice set up. What size duo prop's are you using? 28P's or 30P's and did the nose cone make a difference?

Are there performance props (different pitch) available for the B3's or do they just go by the diameter?

I will be repowering my 7.4MPI (310HP) with a 502MAG (415HP) in the next couple of weeks. My boat come overpropped with the 28P's (WOT@4250RPM) and I'm thinking the 502MAG should be right for them.

I was thinking going the nose cone route since my lower drive needs some painting anyways. Is it worth it or what difference did you notice?

Jamal

Clay Washington

I have a Whipple-charged 502. My Bravo 3 has 1.81 gears. Before the Whipple I was running 28-pitch props, but I could only turn 4400 rpms. After the Whipple I could turn the 28's to 5400 rpms. So, I bought a set of 30-pitch props that had been repitched by Hill Propellers to 31 (maybe 31 1/2). I now turn 5000 rpms.

The props are the same pitch but slightly different diameters. I don't know all the physics, I just know it works!

The additional water requirement of the intercooler did not allow me to use the side water pickups. So, I had a nose cone with a "low-water pickup" installed. Since I did the nose cone at the same time as the Whipple, I can't say if it gave me any additional speed.

The Bravo 3 case is larger than the Bravo 1. You cannot put Bravo 3 gears into a Bravo 1 lower case.

Dave Gilbreath

Hey Clay, still liking those props I see
Dave