Maxx, I have to agree with Brian on this one, as he really is correct.
Even in my own example, I pointed out exactly how he is correct...
"Forced induction does exactly what you said, "increase the pressure" within the cylinders. Although you cannot change the volume of the cylinders, you can change amount of air being forced into that cylinder."
The unit of measure for the amount of air being pressurized into the cylinder is PSI. And exactly like he said, 7 PSI = 7 PSI.
Take a step back and look at it in a elementary level. Take an empty 2 liter soda bottle. Now if you can use a hair dryer to fill stuff it with air, or you can use an air compressor. Either way, once its filled and becomes pressurized, that pressure is measured in PSI. It doesn't matter what is creating that pressure, the pressure inside the bottle is the same, no matter what you used to fill it. 7psi = 7psi
Maximum Boost by Corky Bell
Chapter 3, pages 26 to 30
I don't want to type that many pages, I'll post the main highlight:
"Compressor Efficiency. In concept, compressor effieceny is a measure of how well the compressor wheel can pump air without heating the air more than thermodynamic laws say it should... All compressor wheels operate within peak percentage efficiencies in the seventies. Choosing compressor size becomes mostly a question of where that compressor's efficiency peaks with respect to the flow capabilities of the engine/turbo system."