The Generation 4 car was the NASCAR vehicle generation used from 1992 to 2007 full-time in the NASCAR Cup Series, in the Busch/Nationwide Series until 2010, and in the ARCA Racing Series until 2017. The generation has been described as the generation that removed all "stock" aspects from stock car racing and as aerodynamically sensitive as a Le Mans Prototype. Generation 4 cars feature highly modified bodies with teams to spending hours in the wind tunnel to gain aerodynamics. The bumpers, nose and tail composed of molded fiberglass based on production counterparts.