Bravo 3's to Bravo XR's
 

Is it a direct interchange to go from B3's to XR drives?
Same mount holes, but different Gimbal set-ups?

Or is this a ridiculously complicated swap?

Carder

Completely interchangable, gimbal is the same. At least for the newer ones (serial 0M +) if older there is a kit for under $100 to convert.

Thanks for the expertise!!

Those Bravo 3's Are What Make's The Big Boat Manuver So Well Around The Dock And Also Get Up On Plane

My brother in-law tried that on his Formula and only gained 1-2 mph but did not like the way it handled so put the B3 back on.

Excursion,
Thanks for the input, and thanks for sharing your Avatar!!!

Carder

Carder: I was looking at an 02 38 ec and the guy went from b3 to B1 and gained 4 mph. I plan on trying it with my 06, I actually have some extra b1's from my formula 419. I'll let you know how it goes.

Bravo III to XR
 

We have done several of these swaps. The main thing to consider is that manufactures usually put the Bravo III drives about 2" deeper into the water. (lower X dimension)
To perform a true "apples to apples" swap, you would need to bolt on an XR w/ a 2" shorty lower.

I first did this on my 257 Carrera party cat in 1998. It went from 68MPH to 74MPH. However, the best part was then adding more HP and achieving 102MPH... :D

38fountainecman,
I am dying to here your results after the switch.

Carder

shorty
 

I have a 2 inch shorty lower set up complete , when it was on the boat with the bravo xr top half we had the 1.5 final gear ratio , if intersted let me know and i figure out a price. Rick T.

T/Motorsports, Do you have two? figure me out a price. I in Orlando and can pick them up.

Carder

tried the set up today, 70 deg. flat water b1 1.50:1 26" bravo 1 four blades, spinning out, no toe in or toe out on drives, set up exactly straight on

3400 rpm 43 mph drives @1.5 tabs @ 4.5
4800 rpm 64 mph drives @ 5 tabs @1 (wide open throttle)
4000 rpm 54.5 mph drives @ 3 tabs @ 3.5

boat came on plane just slightly longer than b3, with rpm maxing out @ 4000 when coming on plane. probably should have 24's B1 four blades to get the rpm up to 5000/5100. Had to trim out too far to get to 4800. boat seamed to run smoother with less vibration with the b1's. driving around dock was fine. Also, boat ran best with very little trim on drives, 1.5 to 2.5. I'm thinking of trying my b1 lowers on my b3 uppers which should give me a 1.81:1 ratio and maybe trying my 28 b1's from the formula. Also, I'm interested in trying 2" imco shorties with maximus 5 blades. My recent previous best speed with the b3 setup and all the crap I've put in the boat is 59 mph, so I did get 5 mph in the setup change.

38,
That is impressive, especially on a virgin first run.
I agree with you that you haven't got the best prop/drive ratio set-up yet, but I like your thinking on the other combos.
Please keep me posted, I am living vicariously through your boating. We have about 16 in of ice on Lake Huron, and am looking at several thousand ice fisherman where boats should be.
Carder

Never thought about the x being different. I went from B3's to B1's on my 38. I put bigger power in at the same time so I really don't know the differences for stock. I'm going to check with other owners that have 38's that came with B1's and see if the X is different.....Great info.

Got my answer...the X-dem is the same on a 38 Special.

Boatman22

I do agree the x-dim on the b3 and b1 are the same. What I think billet was saying is that boat manufacturers set up the b3 deeper in the water. I've always thought that Bajas (and the 3 Formula's I've owned) have always had conservative x-dims. I read that Reggie raised the x-dims on some of the newer Fajas and gained some top speed while not loosing any other performance standards, he did add external hydraulic steering to compensate though. I think he set up the 38 Express cruiser with a conservative x-dim partly because of the cruiser aspect of the cockpit floor. My engine hatch (also cockpit floor) almost sits on top of the 496 plastic cover, so while the boat may benefit from a higher x-dim, Fountain didn't want to sacrifice other design aspects of the boat. My thought on the 2" shorty is that it would be real easy to add spacers if the x-dim ends up too high.