Which is best for increased HP: Displacement or overall number of cylinders?
We have all heard the term that, "There is no replacement for displacement," in reference to the ability of an engine to make power. The more fuel that you can put through an engine at a given time, the more power you can make as a result. Turbocharging an engine can affect this to some degree.
So if you have 2 engines, one with 4 cylinders and another with 8 cylinders, both with the same bore, stroke, and piston size, you would expect the engine with 8 cylinders to make more power than the engine with 4 cylinders. Playing with the piston size of the smaller engine will allow it to make more power. Adding a turbo will also do the same thing, as would changing its stroke. These are all easy concepts to visualize.
However, I am having difficulty understanding exactly how torque and horsepower are affected by these concepts. For example, consider the two engines mentioned above. Obviously, the 8 cylinder engine will have more HP and TQ than will the smaller 4 cylinder. However, consider now a different scenario.
Engine 1: NA 8 cylinder with a given bore (X), a given stroke (Y). Engine 2: NA 4 cylinder with a larger bore than the 8 cylinder (2X), but 1/2 the stroke of the 8 cylinder (1/2Y). Engine 3: NA 4 cylinder with 1/2 the bore of the 8 cylinder (1/2X), but twice the stroke of the 8 cylinder (2Y). All engines have the same displacement, but would they all produce the same TQ and HP all other things being equal?
My question is whether for engines of a given displacement, is it more beneficial to have more cylinders and thus more smaller fuel combustions at any given time, or to have less cylinders and thus fewer larger fuel combustions at any given time. In other words, if someone created a 2.0L I8 would it have more TQ and HP than an 2.0L I4?
Someone help a brother out.
R
We have all heard the term that, "There is no replacement for displacement," in reference to the ability of an engine to make power. The more fuel that you can put through an engine at a given time, the more power you can make as a result. Turbocharging an engine can affect this to some degree.
So if you have 2 engines, one with 4 cylinders and another with 8 cylinders, both with the same bore, stroke, and piston size, you would expect the engine with 8 cylinders to make more power than the engine with 4 cylinders. Playing with the piston size of the smaller engine will allow it to make more power. Adding a turbo will also do the same thing, as would changing its stroke. These are all easy concepts to visualize.
However, I am having difficulty understanding exactly how torque and horsepower are affected by these concepts. For example, consider the two engines mentioned above. Obviously, the 8 cylinder engine will have more HP and TQ than will the smaller 4 cylinder. However, consider now a different scenario.
Engine 1: NA 8 cylinder with a given bore (X), a given stroke (Y). Engine 2: NA 4 cylinder with a larger bore than the 8 cylinder (2X), but 1/2 the stroke of the 8 cylinder (1/2Y). Engine 3: NA 4 cylinder with 1/2 the bore of the 8 cylinder (1/2X), but twice the stroke of the 8 cylinder (2Y). All engines have the same displacement, but would they all produce the same TQ and HP all other things being equal?
My question is whether for engines of a given displacement, is it more beneficial to have more cylinders and thus more smaller fuel combustions at any given time, or to have less cylinders and thus fewer larger fuel combustions at any given time. In other words, if someone created a 2.0L I8 would it have more TQ and HP than an 2.0L I4?
Someone help a brother out.
R
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(Torque x Engine speed) / 5,252 = Horsepower