The first evolution of Honda S2000 was known as the AP1. Launched for the 2000 model year, the S2000 was powered by Honda's F20C 2.0L naturally aspirated inline 4 engine. A highly regarded engine, the F20C had the highest specific output of any naturally aspirated engine (123hp per liter). The AP1 was followed up by the S2000 AP2 for the 2004 model year.