Why go easy on it when coming on plane?
12-12-2012 | 06:55 PM
#61
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Joined: Oct 2007
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From: woodstock NY
my boats a 1989 23 ft with the original bravo 1 it has 680 hp 540 in it for the last 4 years and a 500 hp 502 for 6 + years before the 540. go easy to get on plane except a few times for a couple jet ski guys who thought they could take me out of the hole from a dead stop!! i keep my fingers crossed every year!!!! I think the 3000lb weight is what saves it.
12-12-2012 | 09:42 PM
#63
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From: San Diego
My Experience.
High X dimention, high rpm take offs break stuff because of vibration because the way it is slipping.
Low x (underwater) propellers can break stuff on take off because it is grabbing enough to put a torque strain on the drive.
High X dimention, high rpm take offs break stuff because of vibration because the way it is slipping.
Low x (underwater) propellers can break stuff on take off because it is grabbing enough to put a torque strain on the drive.
12-12-2012 | 10:47 PM
#64
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From: Pasadena, MD
Like said, if you like to break stuff then go for it. And thinking that boats are the only thing you cant firewall... I don't know about you all but I don't firewall any of my cars from a dead stop. Even back when I had hot rods all it takes is a twisted driveshaft or blown rear or tranny and you will only do it very select times. If you do it every joy ride you rides wont be very joyous long and the same goes with boats.
12-13-2012 | 08:00 AM
#65
Frank's Marine Service
Joined: Sep 2002
Posts: 11,959
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From: Elkton, MD
If you hammer it out of the hole and the prop is hooked up (low slip), you're just lugging the drive at low rpm. If the engine makes enough power you can even have low rpm detonation.
When we're up and running we have inertia on our side and the boat is on plane so when we give throttle input it translates into more speed pretty quickly. Even then, I don't hammer down with 875 hp a side.
12-13-2012 | 02:02 PM
#66
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Joined: Jul 2006
Posts: 874
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From: Charleston, il
My boat has a high X. When getting on plane, the big cleavers cavitate a lot. 4000RPM on the tachs is common before she even begins to lay over. However, at 4000RPM, Im at about half throttle, and the engines are still in vacuum on the gauge (supercharged). Im less worried about the drives in that scenario, as my engines spinning 4000RPM with cold oil in them still.
Shock loads breaks stuff. Take a piece of glass, like a car window. You can stand on it and not break it. However tap it with a ball peen hammer gently and watch it shatter. When a street car bolts some slicks on and heads to the track and dumps the clutch at the line, he snaps the axles, u-joint, etc. It doesn't normally snap things when the engine is pulling hard say in 3rd gear making gobs of torque in high boost.
Same goes for my Semi truck. The engines in the trucks put out say 1500 ft lbs of torque. Day in and day out the truck weighs 80,000lbs. From standing starts to uphills. Light turns green let off the clutch, and its full throttle 35lbs of boost, until I get thru the gears up to speed. You know when the u-joints snap, or rear axles snap?? Its when the wheels lose traction and hop (mud/sand), or you dump the clutch at full throttle. Hence the hammering effect.
So, in my opinion, what eats up drives, isn't the planning aggressively(not suggesting go from idle to WOT planning), its the unloading and loading them (airing out) and what not. Race boats with mild power eat up #6's, because the drives are always being pushed hard in rough water. Of course this doesn't apply to the guy running 1000's in front of his XR's. The only way not to break the drive would be leave it on the trailer.
Shock loads breaks stuff. Take a piece of glass, like a car window. You can stand on it and not break it. However tap it with a ball peen hammer gently and watch it shatter. When a street car bolts some slicks on and heads to the track and dumps the clutch at the line, he snaps the axles, u-joint, etc. It doesn't normally snap things when the engine is pulling hard say in 3rd gear making gobs of torque in high boost.
Same goes for my Semi truck. The engines in the trucks put out say 1500 ft lbs of torque. Day in and day out the truck weighs 80,000lbs. From standing starts to uphills. Light turns green let off the clutch, and its full throttle 35lbs of boost, until I get thru the gears up to speed. You know when the u-joints snap, or rear axles snap?? Its when the wheels lose traction and hop (mud/sand), or you dump the clutch at full throttle. Hence the hammering effect.
So, in my opinion, what eats up drives, isn't the planning aggressively(not suggesting go from idle to WOT planning), its the unloading and loading them (airing out) and what not. Race boats with mild power eat up #6's, because the drives are always being pushed hard in rough water. Of course this doesn't apply to the guy running 1000's in front of his XR's. The only way not to break the drive would be leave it on the trailer.
12-13-2012 | 09:07 PM
#68
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From: Gunnison Co
And as far as the post you responded to I have dropped the hammer on my Ford stock rear end at my current 438 hp 445 tq that was designed for 280 HP many times and still going strong.
