Porsche flat-six engine

The Porsche flat-six engine series is a line of mechanically similar, naturally aspirated and sometimes turbocharged, flat-six boxer engines, produced by Porsche for almost 60 consecutive years, since 1963. The engine is an evolution of the flat-four boxer used in the original Volkswagen Beetle.

The flat-six engine is most often associated with their 911 model, Porsche's flagship rear-engined sports car which has used flat-six engines exclusively since 1963. The engines were air-cooled until 1999, when Porsche started using water-cooled engines.

In April 2011, Porsche announced the third generation of the 997 GT3 RS with an enlarged 4.0-litre engine having a power output of 500 PS. The naturally-aspirated 4.0-litre flat-six engine (the largest engine offered in a street-legal 911) was introduced with their 911 (997) GT3 RS 4.0, in 2011. The engine itself uses the crankshaft from the RSR with increased stroke dimensions (from 76.4 mm to 80.4 mm). This change increased the power output to 500 PS at 8,250 rpm and 460 Nm of torque at 5,750 rpm. giving it a power-to-weight ratio of 365 hp per ton. Only 600 cars were built. At 493 hp, the engine is one of the most powerful six-cylinder naturally aspirated engines in any production car with a 123.25 hp per litre output.

Other Porsche models that use flat-six engines are the 1970–1972 Porsche 914/6 (mid-engine), the 1986–1993 Porsche 959 (rear-engine), and the 1996–2021 Porsche Boxster/Cayman (mid-engine).

The Porsche 962 sports prototype also used a twin-turbocharged flat-six engine.

Porsche

 * 1963–present Porsche 911
 * 1963–1989 original Porsche 911
 * 1989–1993 Porsche 964
 * 1994–1998 Porsche 993
 * 1997–2006 Porsche 996
 * 2004–2013 Porsche 997
 * 2011–2019 Porsche 991
 * 2019–present Porsche 992
 * 1970–1972 Porsche 914/6
 * 1986–1993 Porsche 959
 * 1996–present Porsche Boxster
 * 2005–present Porsche Cayman

Race cars

 * Porsche 914/6 GT
 * Porsche 934
 * Porsche 934/5
 * Porsche 935
 * Porsche 936
 * Porsche 956
 * Porsche 961
 * Porsche 962
 * Porsche WSC-95
 * Porsche 911 GT1
 * Porsche 911 GT2
 * Porsche 911 GT3
 * Riley MkXI/Riley MkXX/Riley MkXXII/Riley MkXIVI