Then inform me and make me smarter, you need air and fuel and a spark for power, more air and fuel means more power. Hence forced induction psi greater then atmospheric pressure entering the motor. Am I right so far? A small turbo at 5 psI does not offer the same cfm as a large turbo with a different AR or "trim" at the same 5 psi on a gauge. So the larger turbo will produce more hp at 5 psi given that there is sufficent fuel and combistion occurs properly. Tell me where I am missing something so I can better understand you.