Complex sentence: A ram-air intake is any air system in the intake which uses the air pressure created by vehicle motion to increase the air pressure inside of the intake manifold on an engine, thus allowing a greater volume of intake air, and hence engine power.
Split into simpler sentences: A ram-air intake is any air system in the intake which uses the air pressure created by vehicle motion to increase the air pressure inside of the intake manifold on an engine. These allow a greater volume of intake air, and hence engine power.