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psia (absolute)
But my concern is with throttle closed during the intake stroke the pressure above the piston is much less than the pressure below the piston, therefore as the piston is pulled down it requires energy from the flywheel and the car.
Next the piston starts back up and the intake valve closes but now the higher pressure below the piston is helping to push it up. So energy is returned to the flywheel or at least cancels some friction. And when the piston gets to the top it has very little air to compress.
Now both valves are closed and the piston starts down the power stroke, again less pressure on the top of the piston, so energy is taken from the flywheel. But this time near the bottom the exhaust valve opens and exhaust gets pulled back into the cylinder. Then the piston comes up and has to push the gas back out the exhaust port. Exhaust closes, intake opens the cycle repeats.
With wide open throttle (ignition off) the cylinder fills requires energy, requires a lot of energy to compress, returns energy during power stroke, and requires energy to push the air out on the exhaust stroke.
It looks like losses might be higher at WOT. But nothing jumps out at me to say that I have isolated pumping losses.
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