My Addiction

What is the weakest part of the standard Bravo drive?Upper, Lower, gears. ect.?

Can you put an XR lower on a standard bravo upper?

CB-BLR

upper gears.

Chris

Griff

The upper gears are the weak point for sure. I don't know if the XR lower will mate up, but really you need a stronger upper, not lower.

Mr Gadgets

Depends on the year.. The OL and older B1's have thin floored gears.. Weak point #1. You replace the upper gear set and next is the tower in the case.. #2. If you run LH.. then the top cap #3. Then if you replace all that, the case flexs.. #4. This is the upper..
Lower, 1" propshaft is two piece, sometimes they snap, usually a problem with cats. Then the lower gears are a weak point. They used to last 300hrs, or better.. Now it seems they come apart after 100 or so.
So the list goes one. They can be built to eliminate most of the problems. But the history of the Bravo, we have been chasing weak points..
Hope that helps.
Dick

apollard

Mr Gadgets - a quick question.

I have a 26' PowerQuest 7.4 w/ BIII, and will not be going above 450hp, more likely 400 or so (still need to pull the kiddos). So, I was thinking the stock BIII would take the extra 100 hp. True? Are the weak points evident with a stock / near stock install?

Itsallgood995

What about the newer swept back style w/ the better gears & stiffer upper case. Is it fair to say its as strong as the older style bravo x?

Mr Gadgets

Apollard,
I am not very familar with the BIII. I have been told the lower vertical shaft is the weak point, but I have little to no experience with them. The upper is the same as a B1. I believe they have an XR BIII?? The problem with the III is the massive blade area. If you apply too much torque, and something wants to give, it will be the drive. If driven with respect, I would think 400hp would be doable. It all depends on how much power (torque) you have when coming on plane and accelerating when the hull is wet. Too much at that point and things may break. Maybe others have gone down your road and can chime in..

All good, there are good points and bad ones to each of the two drives. The upper cases of the B1's have been made stronger at differnt points, thicker in certain areas, compared to the 90's. The X gears, combined with steel towers in the case and cap do a lot for helping them live. The old style B1 X and the new one use the same gears. The Ribbed top cap with steel tower is a good addition. If you were to add the top cap and studs to the old style case, it has an advantage of a thicker snout. But the over all stiffness may be better with the new OW case. But I am basing that on a drive a friend had with OW case, XR gears and was running 1170hp through it. It had an early maintance schedule, but it never broke.
I would put both the old and new B1 X in about the same class.

It has always been my opinion that if you have enough power to snap the teeth off the helical gears (including the X gears, they are the same gear with a thicker floor), then you need to move up a XR gears. But these days I recommend stepping up to the SCX and bypass the expense of XR gears. If you are going to go big in the motor department, go right to the big dawg and use the SCX.. if you are staying with the bravo style drive.
Whew.. lots of food for thought there!
Hope that helps.
Dick

thirdchildhood

iTrader: (6)

Upper gears went on mine. The XR/Imco is holding up so far.

apollard

Thanks, it gives me some input. I try to take it easy on the launch. The boat is a 26' powerquest that weighs 4800# dry, so if you do go full throttle from rest, it launches it. So much so that it will toss people from seats if they are not facing front, and rearranges everything in the boat. The twin screws do hook up, and low speed / reverse is a dream. There is a speed hit with them. Maybe one day I'll get a BI lower for sh*ts & giggles.