Engine builders, and racers alike, think about improving the performance of their engines using this 4 stroke approach, or what I prefer to call the “old 4 process.” Sometimes people focus on the 4 critical camshaft timing events – intake valve opening (IVO), exhaust valve closing (EVC), intake valve closing (IVC), and exhaust valve opening (EVO) to characterize engine performance. 

This was a good step forward, but a finer breakdown is needed to really understand racing engines. Instead of the traditional 4 strokes, the modern high performance engine should be thought of as having 7 distinct individual processes. This “7 process” approach focuses on air flow through the engine and is a result of two decades of research