800hp through an xr drive
03-30-2015, 06:53 AM
#81
I'm running about 740 hp each through my XR/Sportmasters. What I've found at that power level is even if you are real careful on the sticks, (leaving water etc) to avoid breaking upper gears and tearing the upper yoke shaft assembly right out of the case, the lower gears just don't last very long. I typically get about 35 hrs on the lowers before they start to pit and see more metal on the magnets than I'm comfortable with. I then drain, flush and swap them from side to side, to get more life by running the back side of the lower gears and using up what would have been the reverse gear. By doing so, I've been able to get 70-80 hrs out of them before rebuilding. Make no mistake, they are garbage and a lot of work at higher power levels. If you're not doing your own rebuilds, it can get very expensive fast.
And yes, if I'm on vacation at another lake, (LOTO, etc) I always travel with a spare drive in the bed.
And yes, if I'm on vacation at another lake, (LOTO, etc) I always travel with a spare drive in the bed.
Last edited by Biggus; 03-30-2015 at 06:57 AM.
03-30-2015, 05:16 PM
#82
Banned
iTrader: (9)
I am not saying that thermal shock is the only factor of a hot outdrive on long hard runs then within a blink of an eye gets dunked for 20 to 50 degree temp change just like that that is killing the Bravo. IMO it sure does not help. You have different forms of metals thru out the drive, all metals do not heat up nor cool at the same rates plus all metals do not expand and contract at the exact same rates rates,. Also the gear case is not as strong as you think it is that is supporting a lot of this nor is the top cap..
Also gear pitting is nothing new and can boiling down to Gear corrosion during the manufacturing process. There is forms of this called Pitting corrosion, Crevice corrosion and Intergranular corrosion.
Pitting corrosion is pitting or can be a form of corrosion that was already induced when the gear(s) were manu. It can cause failure by perforation while producing only a small weight loss on the metal. Also the pits are generally small and often remain undetected.
Also gear pitting is nothing new and can boiling down to Gear corrosion during the manufacturing process. There is forms of this called Pitting corrosion, Crevice corrosion and Intergranular corrosion.
Pitting corrosion is pitting or can be a form of corrosion that was already induced when the gear(s) were manu. It can cause failure by perforation while producing only a small weight loss on the metal. Also the pits are generally small and often remain undetected.
Last edited by BUP; 03-30-2015 at 08:30 PM.
03-30-2015, 06:09 PM
#83
Registered
I'm not saying I agree or disagree with his theory, but it as you pointed out the the thermal expansion/contraction is faster in low viscosity fluid than in air. Like MUCH faster. Don't quote me, but I seem to recall water is about 3,400 times more efficient than air in removing heat.
Another variable to consider is the outer case/housing on a bravo would be experiencing this rapid cooling, the internal parts (gears, bearings, etc) would be cooled at a slower rate after submersion in cool water. This internal/external delta could account for significant dimensional clearance and tolerance issues which might be enough to cause failure in a marginal product that's highly stressed and close to it's failure point to begin with.
Again, I'm not sure I think this is a major cause of failure, but the theory at least has some merit.
Another variable to consider is the outer case/housing on a bravo would be experiencing this rapid cooling, the internal parts (gears, bearings, etc) would be cooled at a slower rate after submersion in cool water. This internal/external delta could account for significant dimensional clearance and tolerance issues which might be enough to cause failure in a marginal product that's highly stressed and close to it's failure point to begin with.
Again, I'm not sure I think this is a major cause of failure, but the theory at least has some merit.
03-30-2015, 06:31 PM
#84
Platinum Member
Platinum Member
The smart thing to do is sell your bravos before they blow up and buy IMCO SCX drives
that way you will end up spending about what it is going to cost you WHEN you do blow the drives ( the first time)
after that its all good
that way you will end up spending about what it is going to cost you WHEN you do blow the drives ( the first time)
after that its all good
04-03-2015, 08:17 PM
#87
Curious as to the $$$ difference between the bmax and scx and why you went with the bMax. Let us know what you get for speed. What ratio were/are you running
04-04-2015, 09:49 AM
#89
Registered
Just thought I would add this about my stock 425hp boat. The previous owner sent the drives to AADS and had them built to handle 700hp. I'm a stickler on maintenance and focus on keeping the boat in the water.
My port drive let loose last year despite what I know as proper driving, showers, and maintenance. However, I called AADS and honoring their 2yr warranty George said send it up because failures are rare and he wants to make it right. Lost a vertical shaft. He said oil and everything else was perfect and despite a quality party he felt it was a bad casting. Fixed it at no charge and sent it back.
Build it right. Build from those you trust. Due diligence with care and things can still happen. However, I'm glad the drives came from George and I'm set to run the water.
My port drive let loose last year despite what I know as proper driving, showers, and maintenance. However, I called AADS and honoring their 2yr warranty George said send it up because failures are rare and he wants to make it right. Lost a vertical shaft. He said oil and everything else was perfect and despite a quality party he felt it was a bad casting. Fixed it at no charge and sent it back.
Build it right. Build from those you trust. Due diligence with care and things can still happen. However, I'm glad the drives came from George and I'm set to run the water.
04-04-2015, 10:00 AM
#90
Registered
iTrader: (5)
Just thought I would add this about my stock 425hp boat. The previous owner sent the drives to AADS and had them built to handle 700hp. I'm a stickler on maintenance and focus on keeping the boat in the water.
My port drive let loose last year despite what I know as proper driving, showers, and maintenance. However, I called AADS and honoring their 2yr warranty George said send it up because failures are rare and he wants to make it right. Lost a vertical shaft. He said oil and everything else was perfect and despite a quality party he felt it was a bad casting. Fixed it at no charge and sent it back.
Build it right. Build from those you trust. Due diligence with care and things can still happen. However, I'm glad the drives came from George and I'm set to run the water.
My port drive let loose last year despite what I know as proper driving, showers, and maintenance. However, I called AADS and honoring their 2yr warranty George said send it up because failures are rare and he wants to make it right. Lost a vertical shaft. He said oil and everything else was perfect and despite a quality party he felt it was a bad casting. Fixed it at no charge and sent it back.
Build it right. Build from those you trust. Due diligence with care and things can still happen. However, I'm glad the drives came from George and I'm set to run the water.
Your story is the TRUTH about Bravo based drives, no offense to you personally.
Funny how some think 800hp is ok if you do this or that magic. But no matter what they WILL prematurely fail and or break!
This story proves how they break behind stock engines, then even when drives are UPGRADED to support 700hp they still break behind STOCK 425hp.
Last edited by offshorexcursion; 04-04-2015 at 11:20 AM.
