2 small blocks or 1 big block
03-11-2011, 03:20 PM
#52
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I think the balance of a single engine is a catch 22. Obviously the rear of a twin is heavier, but the torque steer you get with a single can make the boat land on its side when it launches and will have a tendency to not run level. You will alway be messing with the tabs just to get it to drive level. In a twin, your just pointing the nose up or down. In a single your doing the same, but your also trying to get it level.
Were is that kryptonite video mastercraft posted. Watch when it launches the boat dipped to the starboard or port (can't remember) he didn't come down flat. I have had numerous bad landings trying to manage the torque steer of my old 24 python, which is why I sold it. The twin engine boat I have now is 5 times easier to drive, granted it doesn't have a pad bottom like the 24, but it was the torque steer that drove me nuts. Why do you think mercury made a special NXT drive just for single engine boats?
Were is that kryptonite video mastercraft posted. Watch when it launches the boat dipped to the starboard or port (can't remember) he didn't come down flat. I have had numerous bad landings trying to manage the torque steer of my old 24 python, which is why I sold it. The twin engine boat I have now is 5 times easier to drive, granted it doesn't have a pad bottom like the 24, but it was the torque steer that drove me nuts. Why do you think mercury made a special NXT drive just for single engine boats?
Last edited by TexomaPowerboater; 03-11-2011 at 03:22 PM.
03-11-2011, 03:28 PM
#53
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[QUOTE=TexomaPowerboater;3348219]I think the balance of a single engine is a catch 22. Obviously the rear of a twin is heavier, but the torque steer you get with a single can make the boat land on its side when it launches and will have a tendency to not run level. You will alway be messing with the tabs just to get it to drive level. In a twin, your just pointing the nose up or down. In a single your doing the same, but your also trying to get it level.QUOTE]
You hit the nail on the head with the torque steer. Plus i think the twins being a little heavier; give you a little softer ride in the rough.
You hit the nail on the head with the torque steer. Plus i think the twins being a little heavier; give you a little softer ride in the rough.
03-11-2011, 04:33 PM
#54
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Also, the fuel savings on a single engine boat vs a twin is not much. I would venture to say that a twin engine boat will use only 10-20% more fuel than a single at cruising speeds. That is because it takes 4000rpm on a single to do what 3000 rpm does for a twin application. Once you get past 3000-3200rpm the fuel consumption increases dramatically. This is also why the twin setup is often more reliable and can have more hours before rebuild.
Of course if you drive WOT all the time these facts go right out the window.
Of course if you drive WOT all the time these facts go right out the window.
03-11-2011, 07:38 PM
#55
JC Performance Engines
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03-11-2011, 07:42 PM
#56
JC Performance Engines
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I think the balance of a single engine is a catch 22. Obviously the rear of a twin is heavier, but the torque steer you get with a single can make the boat land on its side when it launches and will have a tendency to not run level. You will alway be messing with the tabs just to get it to drive level. In a twin, your just pointing the nose up or down. In a single your doing the same, but your also trying to get it level.
Were is that kryptonite video mastercraft posted. Watch when it launches the boat dipped to the starboard or port (can't remember) he didn't come down flat. I have had numerous bad landings trying to manage the torque steer of my old 24 python, which is why I sold it. The twin engine boat I have now is 5 times easier to drive, granted it doesn't have a pad bottom like the 24, but it was the torque steer that drove me nuts. Why do you think mercury made a special NXT drive just for single engine boats?
Were is that kryptonite video mastercraft posted. Watch when it launches the boat dipped to the starboard or port (can't remember) he didn't come down flat. I have had numerous bad landings trying to manage the torque steer of my old 24 python, which is why I sold it. The twin engine boat I have now is 5 times easier to drive, granted it doesn't have a pad bottom like the 24, but it was the torque steer that drove me nuts. Why do you think mercury made a special NXT drive just for single engine boats?
03-11-2011, 11:24 PM
#58
Registered
I think the balance of a single engine is a catch 22. Obviously the rear of a twin is heavier, but the torque steer you get with a single can make the boat land on its side when it launches and will have a tendency to not run level. You will alway be messing with the tabs just to get it to drive level. In a twin, your just pointing the nose up or down. In a single your doing the same, but your also trying to get it level.
Were is that kryptonite video mastercraft posted. Watch when it launches the boat dipped to the starboard or port (can't remember) he didn't come down flat. I have had numerous bad landings trying to manage the torque steer of my old 24 python, which is why I sold it. The twin engine boat I have now is 5 times easier to drive, granted it doesn't have a pad bottom like the 24, but it was the torque steer that drove me nuts. Why do you think mercury made a special NXT drive just for single engine boats?
Were is that kryptonite video mastercraft posted. Watch when it launches the boat dipped to the starboard or port (can't remember) he didn't come down flat. I have had numerous bad landings trying to manage the torque steer of my old 24 python, which is why I sold it. The twin engine boat I have now is 5 times easier to drive, granted it doesn't have a pad bottom like the 24, but it was the torque steer that drove me nuts. Why do you think mercury made a special NXT drive just for single engine boats?
You are right the balance is a catch 22.
However - lighter is always better.
The singles do torque steer but a really good fully hydraulic steering system will minimize this - but it's its still there.
The original NXT "single skeg" was a disaster, and Merc changed it due to handling issues shortly after introduction.
Thing is ...small block parts - like exhaust systems aren't any cheaper than big block parts, and if you put in 2 potent small blocks you will spend very nearly if not more than what you will on big blocks on an HP to HP basis. The small block guy will still have a much harder time finding parts.
( I know because I built, and still own a potent small block boat)
So in a sense a good twin small block boat might as well be twin big blocks from a maintenance, cost and parts availability perspective.
True the small blocks are easier on the drives than the BB's.
From my ownership perpective having built both - the realistic choice is really a single BB or twin BB's.
Uncle Dave
03-12-2011, 05:14 AM
#59
You are right the balance is a catch 22.
However - lighter is always better.
The singles do torque steer but a really good fully hydraulic steering system will minimize this - but it's its still there.
The original NXT "single skeg" was a disaster, and Merc changed it due to handling issues shortly after introduction.
Thing is ...small block parts - like exhaust systems aren't any cheaper than big block parts, and if you put in 2 potent small blocks you will spend very nearly if not more than what you will on big blocks on an HP to HP basis. The small block guy will still have a much harder time finding parts.
( I know because I built, and still own a potent small block boat)
So in a sense a good twin small block boat might as well be twin big blocks from a maintenance, cost and parts availability perspective.
True the small blocks are easier on the drives than the BB's.
From my ownership perpective having built both - the realistic choice is really a single BB or twin BB's.
Uncle Dave
However - lighter is always better.
The singles do torque steer but a really good fully hydraulic steering system will minimize this - but it's its still there.
The original NXT "single skeg" was a disaster, and Merc changed it due to handling issues shortly after introduction.
Thing is ...small block parts - like exhaust systems aren't any cheaper than big block parts, and if you put in 2 potent small blocks you will spend very nearly if not more than what you will on big blocks on an HP to HP basis. The small block guy will still have a much harder time finding parts.
( I know because I built, and still own a potent small block boat)
So in a sense a good twin small block boat might as well be twin big blocks from a maintenance, cost and parts availability perspective.
True the small blocks are easier on the drives than the BB's.
From my ownership perpective having built both - the realistic choice is really a single BB or twin BB's.
Uncle Dave
Do you think 2 BB's will fit in the engine room of a Scarab 29 ?
Hydraulic steering does nothing to counteract the torque from a single propeller.
If we consider stock power you could compare stock 350 Mag MPIs (300 HP) to eg. a HP500, my guess is that most likely you will get many more hours out of the small blocks without any need to rebuild anything compared to a HP500.
If you want a lot more horsepower out of a stock setup I agree BB is the way to go.
