whats the power limit for bravo's?

[ekoster]

I've got a marine shop in stockton, ca. Started there about a year and a half ago, and recently purchased it. We've never really gotten into performance stuff for boats, though I do have good background in automotive performance. What I'm trying to find out is, what kind of power can be safely put through bravo drives? The customers boat is a 1999 32' scarab. It currently has twin 502 mag mpi's. It goes 75mph, he wants me to make it go 100mph. What kind of hp/tq numbers will I need and what should I be looking at for the drives? Thanks
Eric

[Beer-30]

Well, the new Bravo-1X is rated at 425 HP, and about 450-500 ft lbs. Those of us with big boats, 425+ HP, and a standard Bravo are REAL easy on our drives, as Merc realized the standard Bravo wasn't cutting it for too long under 502s and 496s. Although, there are several peeps here on the boards running moderate blower motors with B-1s and they are living. I think keeping good lube (I run synthetic TORCO racing trans lube), and just driving it sanely is just common sense.
I am sure others here will back me up on the prescription for your client:
If the 502s are in good shape internally, low hrs and such, I would say a Whipple / apiece. That will take the 502 into the 650 HP range.
If he/she wants to run the B-1s till they puke, so be it. Otherwise, money permitting, throw on two Bravo-XRs. They are made to handle that kind of HP.
Optional would be nice exhaust. Again, money permitting.
Does that help?

[ekoster]

yes beer-30. thanks for the info. Would 650hp a piece be enough to push that boat to 100 mph? The engines seem to be in good shape, I just pulled them to change out some stripped drive couplers. I thought a blower or a set of low pressure twin turbos might be sweet. the turbo setups are probably pricey though because you have to deal with water cooling the turbos and such.

[Beer-30]

yes beer-30. thanks for the info. Would 650hp a piece be enough to push that boat to 100 mph? The engines seem to be in good shape, I just pulled them to change out some stripped drive couplers. I thought a blower or a set of low pressure twin turbos might be sweet. the turbo setups are probably pricey though because you have to deal with water cooling the turbos and such.
I have definitely noticed that turbos are much more expensive.
I don't know how pricey your customer wants to get in chasing that triple digit mark. The twin blowers would (guessing) put you in the 90 area. Actually, not being brand-specific, if you go to the Procharger website, they have examples of before/after speeds. Some of them are twins.

[ekoster]

how stout are those 502 mag bottom-ends? Maybe the answer would be to do heads, cams, and the whipples... Seems like that might get him there...

[Beer-30]

Well, like I said, I don't know what kind of $ he/she is looking to spend, but you are right on target. You would be getting into the limits of the bottom end, though.
It is a forged rotating assembly, including pistons. Pretty stout. I think you could do it pretty easy, though. Edelbrock makes a marine head that comes with Inconel exh valves, stainless intakes and no springs, due to different set-ups.
AZ Speed and Marine has a ported intake for those motors. So many cams would work, that would be the hardest to pick. That stuff, nice exhaust and about 6-7 lbs of intercooled boost would put you on the mark.

[ekoster]

very good, well, i'll have to do a little more research I guess. I need to get a budget from this guy first though. This stuff gets expensive quick, then times that by 2.
thanks beer-30
Eric

[Beer-30]

Good luck. Sounds like a fun project, if the money is there!

[ekoster]

yeah. BTW- how do you like your sleekcraft?

[HP350SC]

I would say it will take a solid 850 hp each to get to 100mph, $18K in drive upgrades to be reliable. Might ask his total budget and work backwards from there. Speed isn't cheap.

[Beer-30]

I would say it will take a solid 850 hp each to get to 100mph, $18K in drive upgrades to be reliable. Might ask his total budget and work backwards from there. Speed isn't cheap.
I figured 725-750. 850 would be better! It's a 32 footer. I was thinking originally that it was a35. It only took 1000 (I say only?) HP to get a 30 Heritage like mine to 90 and change. At 750/side, he is looking at 1500. 2 feet longer, extra weight of 2nd motor/drive. Should be close. I think it would be funny to try to make the B-1s live behind it!! Start takin bets on how long?

[Beer-30]

yeah. BTW- how do you like your sleekcraft?
Only had her since January. I have put about 20 hours on. Most of it idling around, partying.
At Mojave in May, I trimmed it up to right at 60 with 8 adults, 3/4 fuel and two ice chests. 4900 RPM. Loud stick full north. The cool thing is, that was in 3 foot rollers. It's a cruiser, not a fighter. All in all, I really do like it. Plenty of room for all my peeps (have had 9 adults/2 children) with room to spare. So much freeboard, everyone stays dry. And as a bonus, it makes my truck look good.