What are my odds?
 

Ok, so Im in the process of putting a roots on my 502, nothing radical but from everything I've been told "its only a matter of time before my Bravo XR will go"! I've read the forums where some people have had no problems while others didn't last 10 hrs, I understand you just don't know. My plans were to put blower on this winter, take it really easy on the bravo all summer and wait till next winter to upgrade to something stronger. But damn! After looking at the cost$$$$ of other lower units, I dont know if I'll have the money saved up by next winter or be wanting to fork out that much $$! Those damn things aren't cheap!! So Im asking you guys with experience in Bravo failers........when yours finally went....1) Was it a complete loss or did you just break something and had to rebuild? 2) How much did that cost ya? 3) Did you rebuild with upgraded parts? 4) Did it just break again? How many times have you rebuilt same unit? 5) Etc.

well I run about 750hp thru a stock bravo 1, run a drive shower and royal purple lube, just don't hammer getting on plane and watch getting airborne with it....been ok for 2 seasons so far...just have to be carefull....

Roots blowers make a lot of torque down low, that is hard on the Bravo drive. Prochargers come on a bit softer in the lower rpms and helps drive life a bit. XR upper gear sets are prone to breakage. When a tooth snaps off, it can, at times make a mess of things! It is a crap shoot at best with them. With the helical gears if you dont over power the teeth, they will last a long time. But torque is a killer on them. Accelerating through the mid range needs to be gentle. A wet hull and too much torque is not good. Once you get the boat lightened up, the drive can better handle the power..
Hope that helps.
Dick

Running 738lbft of torque. Broke a vertical shaft on an XR about 8 hours after I bought the boat. Running around 3,000 rpm's. Totally rebuilt the XR with all the upgraded parts. All new shafts, gears that were Cryo treated... 12 hours broke a tooth off the XR upper gear and cracked the upper case... Total rebuild again but with XZ gears. Lasted 2.5 hours and tore the pinion gear to pieces. Found it was a soft pinion gear right from Mercury. They gave a replacement set (back to XR's) and I still did another full rebuilt again with Cryo gears, new bearings, clutch shaft... and that cost was out of my pocket except for the gears. The drive is sitting in my garage with zero hours and I bought a used Bmax HT and rebuilt it. Put on 25 hours last season and feel good about the Bmax with no issues.
A light boat with a roots style blower and an XR will hold up with easy throttle use but with a 29' single engine it's going to break with that much torque.
Mr Gadgets is right about the wet hull/torque. Broke mine between 3,000 and 3,500 rpm's every time.

What do you mean by "wet hull"? And are Bmax a direct replacement for a bravo? Were you able to use all the same steering rigging? Prop?

Having a reliable running boat is sometimes more fun then a fast boat that breaks down, or being worried about it breaking down all the time.

I personally would not chase the speed unless you have the cashola to do it properly. No offense. I have been there and been very unhappy sitting on land with a broken boat.

Your drive will break, or wear out. Hard to give a accurate estimate since 1 or 2 seasons for one guy is the same as 4 or 5 seasons to the next.

Cost to rebuild a broken drive could be anywhere from $2000 to $8000, and it could happen on average of every 20 to 80 hours in a set up like yours. For my boat I have to rebuild the pair every summer! Sucks!

B-Max are good drives but still use XR lower gears. Johns customer service is excellent. They cost around 13k new.

SCX would be another choice, around the same price new also.

There is no option that is less expensive besides keeping your HP and TQ where its at and enjoying extra fuel money to go boating more often!

Not only will you have to save up for drive repairs and/or upgraded drive. You will also have to rebuild the engine to make it stronger. Eventually you will want even more speed, and more, and more, it never ends untill you choose to be satisfied with what you have. Why not choose to be satisfied now?

This makes the most sense to me, very wise information!!!!!

I'm running whipples on my 525's in a heavy boat with XR's and 5 blades. I change the drive oil and swap right for left at the end of the year. Two seasons, no problems including a bunch of Poker Runs.

i think allot has to do with how you use the sticks. Its not a drag boat, so I am very easy getting on plane and i do not slam the throttles at any time. Just roll it on and back off easy. Also, where I boat it very rarely launches completely out of the water, so the drive is not subject to massive, sudden torque.

Will they go? Probably at some point, but if I was really that worried about breakage I would have left them stock. I just love the performance sound of that supercharger whine and havng a Formula that can run as fast as it does!

Ran bravo X's on a 36 Baja outlaw (heavy and wet) with 500hps and 177 blowers. Never once lost a drive, but lost a few engines.

Keep in mind where you are when you ask this question.

OSO Rules

1. If you have any kind of bravo drive it will break, in fact it is probably already broken
2. If you add a supercharger be prepared to spend another $18k on engine internal upgrades or it will blow up in seconds, probably while idling
3. If your boat has been used in salt water, been parked near saltwater, or if anyone has eaten saltine crackers in the cabin it is shot, just toss it.
4. Nothing less than a 4500 series DRW truck should be used to tow your 29 ft down the block to the launch ramp, in case the trailer brakes go. Most boat towing accidents happen in the launch parking lot, so don't take stupid chances, insurance will not pay.

All kidding aside

Change the oil every 25 hrs, use the best oil possible made for your drive
Pull the upper rear cap and inspect the gears every 25 hrs
If you are spinning the drive LH find a stronger after market top cap. Right now there are a few billet ones on ebay at a good price

If you blow the upper, and do not have access to a great drive shop to inspect, you may consider replacing it with new or after market. The upper case can stretched fairly easy if the gears come apart. Causing premature failure for the next set....and a bad name for bravo's. This is why gear inspection is crucial, catching them before catastrophic failure is key

Wet hull!?
 

This may be a dumb question but, Once again "wet hull" is mentioned. Can someone explain this term? And I have been asking around the area here for someone to go through my lower unit before I re-install it, but not having much luck. Im thinking about just doing an inspection myself for obvious problems like gear teeth conditions but I ve never had one apart before. I feel like I am mechanically inclined enough, but just a visual inspection prob. not enough, is it?? Im guessing there are clearances that would need check too HUH?!