[Nichoms]

From my understanding, learned in several thermo classes, a positive displacement supercharger produces the pressure (boost) inside the case, just as they previously explained, with the air moving down the case in the decreasing space between the rotors, therefore when the air leaves the case it is already pressurized to a set psi. In superchargers that are not positive displacement they just push the air through the supercharger and stack the air ontop of itself in the combustion chamber, or ontop of the intake valve. So the air leaving the supercharger is not pressurized when leaving the case but builds the pressure at the valve simply from the air having nowhere else to go.