For increased power, many M20s also have a ram-air induction system, called the Mooney "Power Boost". For normal operations, the intake air is filtered before it enters the induction system. When ram air is selected, partially unfiltered air enters the induction system with a higher pressure and consequently the manifold pressure increases about a full inch of mercury flying at 7500 feet above mean sea level, giving a greater power output. The turbocharged variants omit this feature, as the turbocharger provides a far greater increase in manifold pressure.