switching from XR to HT B-max
12-02-2007, 03:45 PM
#21
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of course. but from a mechanical or engineering standpoint the weak link is moved and that is fact. same issues on a high powered single engine, busted gimbal.
not blaming or trying to disuade anyone from b-max, just offering info. in my findings the stronger gears, heavier weight hanging from a pivotal point not enginered for, and larger surface area, there is an effect to the overall performance of the vessel and its attributes.
not blaming or trying to disuade anyone from b-max, just offering info. in my findings the stronger gears, heavier weight hanging from a pivotal point not enginered for, and larger surface area, there is an effect to the overall performance of the vessel and its attributes.
I would agree that the weak link does move. That said I have not seen any additional stress in my application. In the threads discussed I believe that an impact with a foreign object had something to do with it. Any upgrade to a weak link is suggested and should be a part of your budget when considering any project. Just as I learned with my modified procharger project. A Bravo is a disposadrive in that application I don't care who is driving it is just a matter of time you'll break it.
12-02-2007, 04:01 PM
#22
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Monstaa,
I would agree that the weak link does move. That said I have not seen any additional stress in my application. In the threads discussed I believe that an impact with a foreign object had something to do with it. Any upgrade to a weak link is suggested and should be a part of your budget when considering any project. Just as I learned with my modified procharger project. A Bravo is a disposadrive in that application I don't care who is driving it is just a matter of time you'll break it.
I would agree that the weak link does move. That said I have not seen any additional stress in my application. In the threads discussed I believe that an impact with a foreign object had something to do with it. Any upgrade to a weak link is suggested and should be a part of your budget when considering any project. Just as I learned with my modified procharger project. A Bravo is a disposadrive in that application I don't care who is driving it is just a matter of time you'll break it.
their is truly a reason why items are designed as a match pair. from an engineering stand point. a similiar analogy would be to analize , from a stress standpoint , the effects of using the "stern jack" on the transom assembly as a whole. big long studs into the helmu with a bilet piece of staock 6-8 inches long. not good.
as for the bravos i feel they are only as good as thier operator.
12-02-2007, 05:45 PM
#23
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as for the bravos i feel they are only as good as thier operator.
When you press over 600 HP thay just can't take it. I have had them grenade on glass flat water while decelerating. Some make them work but I don't think they drive them hard.
I don't know enough of the gimble situation to give an opinion I did not see the parts, etc. I've been OK so far.
When you press over 600 HP thay just can't take it. I have had them grenade on glass flat water while decelerating. Some make them work but I don't think they drive them hard.
I don't know enough of the gimble situation to give an opinion I did not see the parts, etc. I've been OK so far.
12-03-2007, 06:54 AM
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the unfortunare thing is that too many people "rebuild" bravos. once they grenade their petty much junk. guys rebuild them, using the same casing that has been stretched from the previous explosion.this is most of the cause ofmajor failure after initial blow up.
i have set up at least a dozen boats between 35 and 42 with bravos and 750 h.p with out reoccuring failures. and they are here on long island where you have both flat water in the large bays as well as some of the roughest inlets known.
it reall is my feeling that used properly and with proper maintanance they will live with 700+ without problem.
i have set up at least a dozen boats between 35 and 42 with bravos and 750 h.p with out reoccuring failures. and they are here on long island where you have both flat water in the large bays as well as some of the roughest inlets known.
it reall is my feeling that used properly and with proper maintanance they will live with 700+ without problem.
12-03-2007, 05:34 PM
#25
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When installing a b-max drive would really consider an imco hd gimbal,especially on a cat,lots of side load with the high speeds.The b-max is heavier than the standard drive about the same weight as the bravo3(according to dean at bravo shop)the difference is bravo3 boats are lucky to do 65mph not 130mph,breaking gimbals at speed is bad news!!
12-18-2007, 07:14 AM
#27
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Question for Monstaaa, when it comes to a bravo drive life, do you think the oil cooler system from Drew Marine would help?
I think it would help alot in my situation. With a drive temp gage installed I found that I could get the oil in the drive VERY hot, when running hard. If the Drew Marine system keeps the oil temp low all the time, then it 'should ' help with gear and seal life right?
I think it would help alot in my situation. With a drive temp gage installed I found that I could get the oil in the drive VERY hot, when running hard. If the Drew Marine system keeps the oil temp low all the time, then it 'should ' help with gear and seal life right?
12-18-2007, 07:18 AM
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Also, about the B Max, I looked into them last summer when my bravo failed. I found a few draw backs with the B Max. I couldn't run my exhaust through the drive, I would have to buy mufflers. Also with external hydraulic steering, without modification, the steering angle is reduced. This wouldn't help when docking.
Both are liveable issues, but just wanted to add to this thread.
Both are liveable issues, but just wanted to add to this thread.
12-18-2007, 09:16 AM
#29
Geronimo36
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I'm under the impression that B-max only sells there drive with merc 1.36 lower gears or the other steep lower gears because the 1.36 gears have poven to be slightly more durable. I do know they are using merc lower gears,not some extra strong aftermarket version or anything. Has anyone tried re-gearing the drive with merc 15/19 1.50 lower gears? By cryoing then giving the lower gears a multi-step surface treatment that ends with them having a very smooth finish I have gotten the 15/19 1.50 gears to last much longer then they ever did in stock form on my boat with a bravo drive. My understanding is that most boats go slower when switching to a B-max because of the extra friction of the larger upper gears and bearings but what I'm wodering is if some guys are losing speed from the overall gearing and re-propping why not try going back to 15/19 lower gears once the warranty is up,Smitty
I lost 2 mph when I made my switch... I blew two brand new IMCO Extreme SC's (800 hp rated in a 10k boat
) in about 20 hours on 715 HP.... Thus far I ran 100 hrs on the BMax with 715 hp the first year and 830 hp the second year..all ocean running.I had one small issue with the coupler that connects the verticle shaft in the lower to the upper but I've had ZERO downtime since I bought these drives well over two seasons now.
With that being said....100 hrs on them I sent them back to Dean to be fresheshened so I can go another 100+ hours without batting an eye!
12-19-2007, 02:57 PM
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Smitty, from what I understand they couldn't get the 1.50's to hold up for any length of time and that it had something to do with harmonics or something like that. I think the upper gears in the BMax change the gear ratios slightly... It was explained to me in detail about 3 years ago but I don't remember exactly what it was.
I lost 2 mph when I made my switch... I blew two brand new IMCO Extreme SC's (800 hp rated in a 10k boat) in about 20 hours on 715 HP.... Thus far I ran 100 hrs on the BMax with 715 hp the first year and 830 hp the second year..all ocean running.
I had one small issue with the coupler that connects the verticle shaft in the lower to the upper but I've had ZERO downtime since I bought these drives well over two seasons now.
With that being said....100 hrs on them I sent them back to Dean to be fresheshened so I can go another 100+ hours without batting an eye!
I lost 2 mph when I made my switch... I blew two brand new IMCO Extreme SC's (800 hp rated in a 10k boat
) in about 20 hours on 715 HP.... Thus far I ran 100 hrs on the BMax with 715 hp the first year and 830 hp the second year..all ocean running.I had one small issue with the coupler that connects the verticle shaft in the lower to the upper but I've had ZERO downtime since I bought these drives well over two seasons now.
With that being said....100 hrs on them I sent them back to Dean to be fresheshened so I can go another 100+ hours without batting an eye!
