Most chargers sit right over the intake ports of the head/ heads so you wouldn't have any lag, but when you have cooler and piping thats a cavity you need to pressurize. Think of it as a tube, your compressor might have 170psi in its tank but when you squeeze the trigger it takes a minute to start building pressure. I could be wrong i haven't really played with chargers just with turbos and in all my cars i've had them hitting boost at around the factory mark no matter how high its wound.