This inline-four gasoline configuration is the most common in cars with a displacement ( engine size ) up to 2.4 L. Porsche used a 3.0 L four in its 944 S2 and 968 sports cars . This inline engine configuration is the most common in cars with a displacement up to 2.4 L. The usual `` practical '' limit of the displacement of inline-four engines in a car is around 2.7 L. However , Porsche used a 3.0 L four in its 944 S2 and 968 sports cars , and Rolls Royce produced several inline-four engines of 2,838 cc with basic cylinder dimensions of 3.5 i diameter and 4.5 i stroke ( Rolls Royce B40 ) ;