Helping Bravo's Live - Detuning
01-14-2005, 06:54 PM
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Re: Helping Bravo's Live - Detuning
Originally Posted by Reed Jensen
There are two sticks on the dash board..... they are connected to the throttles... move them easily and softly in both directions and you won't have to do anything to the drives................. 
I'm sorry... I don't mean to sound like a smart-a$$.... but sometimes it's not the torque generated by the horsepower that tears stuff up... but the torque from the larger mass of the crankshaft and flywheel twisting the undersized, underengineered parts in the drive. Hard on... hard off... on the throttles can break parts just as quickly as too much HP.
I'm sorry... I don't mean to sound like a smart-a$$.... but sometimes it's not the torque generated by the horsepower that tears stuff up... but the torque from the larger mass of the crankshaft and flywheel twisting the undersized, underengineered parts in the drive. Hard on... hard off... on the throttles can break parts just as quickly as too much HP.
01-15-2005, 12:39 AM
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Re: Helping Bravo's Live - Detuning
A 600 inch motor is gonna make torque no matter what you do to it.
Timing below 28 degrees will just make the exhaust valves run too hot. But it should soften it up a bit.
A throttle stop will limit your top end hp/torque, but you'll still make huge torque at low revs (which is where you'll most likely kill the drives, coming onto plane too hard or accelerating from a slow plane).
You can probably get some custom rockers made at 1.5:1. Will reduce your valve lift by 12%. (from .600 down to .530)? On second thought, that won't kill enough torque down low either, mostly up high.
Take out a couple of pistons?
Timing below 28 degrees will just make the exhaust valves run too hot. But it should soften it up a bit.
A throttle stop will limit your top end hp/torque, but you'll still make huge torque at low revs (which is where you'll most likely kill the drives, coming onto plane too hard or accelerating from a slow plane).
You can probably get some custom rockers made at 1.5:1. Will reduce your valve lift by 12%. (from .600 down to .530)? On second thought, that won't kill enough torque down low either, mostly up high.
Take out a couple of pistons?
01-15-2005, 10:32 AM
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Re: Helping Bravo's Live - Detuning
Reduce the pitch of the propeller by 4 inches. That will take the load off the drive at all rpms. Just don't overrev the engine at the top end.
01-15-2005, 03:16 PM
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Re: Helping Bravo's Live - Detuning
Originally Posted by PatriYacht
Reduce the pitch of the propeller by 4 inches. That will take the load off the drive at all rpms. Just don't overrev the engine at the top end.
01-16-2005, 09:58 AM
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Re: Helping Bravo's Live - Detuning
Patriyacht ... What a great idea. Why didn't I think of that? 
I can drop 3 pitch and still hit 78- 80 mph!!!! I'll get to enjoy the boat till mid-summer when I can do the drive upgrades. THANKS! 
I can drop 3 pitch and still hit 78- 80 mph!!!! I'll get to enjoy the boat till mid-summer when I can do the drive upgrades. THANKS!
01-16-2005, 11:00 AM
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Re: Helping Bravo's Live - Detuning
Originally Posted by PatriYacht
Reduce the pitch of the propeller by 4 inches. That will take the load off the drive at all rpms. Just don't overrev the engine at the top end.
01-16-2005, 12:48 PM
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Re: Helping Bravo's Live - Detuning
redline shockproof heavy in drives. i am a firm believer. blown 540,s 10.000 lb boat 30 inch bravo ones. nrever blown a drive. you will need a bigger resovior as it does tend to expand more than mercury hipo gear lube.
01-18-2005, 08:01 AM
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Re: Helping Bravo's Live - Detuning
I agree with the Redline gear lube and run drive showers. So far I'm having good luck with my overloaded Bravos but my boat never flies and I baby it onto plane.
01-27-2005, 12:22 PM
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Re: Helping Bravo's Live - Detuning
try pulling 1 plug wire off each engine or buy some ssm#3a's i think tommy at chief has 2 complete setups for 10 k he may even take a bit less and sell your drives to offset the cost. then USE that big torque...
