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.^[8][9] The engine is an evolution of the flat-four boxer used in the original Volkswagen Beetle.^[10][11][12]

Porsche flat-6 engine
Overview
Manufacturer	Porsche
Production	1963–present
Layout
Configuration	Flat-6
Displacement	2.0–4.2 L (122–256 cu in)[1]
Cylinder bore	80–102.7 mm (3.1–4.0 in)[2][3]
Piston stroke	66–80.4 mm (2.6–3.2 in)[4][5]
Valvetrain	12-valve or 24-valve, SOHC/DOHC, two-valves per cylinder or four-valves per cylinder[6]
Combustion
Turbocharger	Yes (some models)
Fuel system	Mechanical fuel injection Carburetor Direct fuel injection
Fuel type	Gasoline
Oil system	Dry sump
Cooling system	Air-cooled[7] Water-cooled
Output
Power output	110–850 hp (82–634 kW)
Torque output	119–730 lb⋅ft (161–990 N⋅m)
Dimensions
Dry weight	387–507 lb (176–230 kg)

Porsche flat-6 engine

Flat-6 engine in an older air-cooled 911

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.^[13] The engines were air-cooled until 1999, when Porsche started using water-cooled engines.^{[14][15][16][17]}

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 (368 kW; 493 hp). The naturally-aspirated 4.0-litre flat-six engine (the largest engine displacement offered in a street-legal 911) was introduced with their 2011 911 (997) GT3 RS 4.0, in 2011.^[18] 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 (368 kW; 493 hp) at 8,250 rpm and 460 N⋅m (339 lbf⋅ft) of torque at 5,750 rpm.^[19] giving it a power-to-weight ratio of 365 hp per ton. Only 600 cars were built.^[18][20] At 493 hp (368 kW),^[21] the engine is one of the most powerful six-cylinder naturally aspirated engines in any production car with a 123.25 hp (92 kW) per litre output.^{[22][6][23][24][25]}

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).^[26][27][28]

The Porsche 962 sports prototype also used a twin-turbocharged flat-six engine.^{[29][30][31][32]}

Applications

Road cars

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^[33]
• 1986–1993 Porsche 959
• 1996–present Porsche Boxster^[34]
• 2005–present Porsche Cayman^[35]

Others

• 2014–2018 W Motors Lykan HyperSport
• 2019–present W Motors Fenyr SuperSport

Race cars

• Porsche 914/6 GT
• Porsche 934^[36][37]
• Porsche 934/5^[38]
• Porsche 935^{[39][40][41][42][43][44]}
• Porsche 936
• Porsche 956
• Porsche 961
• Porsche 962
• Porsche WSC-95
• Porsche 911 GT1
• Porsche 911 GT2
• Porsche 911 GT3^[45]
• Riley MkXI/Riley MkXX/Riley MkXXII/Riley MkXXVI