Originally Posted by onehundred80
Vacuum? Lower air pressure is not a vacuum. Vacuum cleaners do not make a vacuum, they pull air away and the surrounding air rushes in to keep things balanced.
Slow and fast moving air is like slow and fast moving water. You can wade across a slow flowing stream 6" deep, try wading across that 6" stream when the water is flowing much faster. Its the force of the water than bowls you over, the water pressure has not changed.
To increase air pressure you have to concentrate more of it into a given volume. The amount of air caught in front of a radiator has to be compressed to get any rise in pressure, the air that is outside the grille cannot do it as it is not there at a sufficient density to act as a ram. The draft behind the grille is just that, a strong draft and it just wants to settle back to the state the surrounding air is in.
Air rushes into a cylinder to fill a void, it does takes power to push more air than nature can provide into the cylinder, and that power would be the SC in this case.
Why is air entering you engine? Because the piston went down in the cylinder and caused a "
vacuum" which is
replaced by ambient air.
Vacuum by definiton does not mean an abscence of air, just a "lower than ambient" pressure. Partial
Vacuum is still genericaly referred to as
Vacuum.
I deal in vacuum enginering all day and have a
vacuum related patent. In any Na engine, what's going on in your intake is
vacuum. That's how the
vacuum that operates
vacuum systems on older cars worked. Using the
Vacuum created in the manifold to operate the wipers, or the locks, or the baffles and gates in your HVAC systems. Also, it was the
Vacuum inside the carburator that made the venturis operate.
And the dial on the gauge many cars have that says,
"Vacuum"
In a fuel injected engine, it'a all about getting "air" to the cylinders. Period.
Got it?
roadster with a stick