List of Subaru engines
Subaru uses a four or five digit code to identify all of their engines.
- The first letter is always E standing for engine.
- The next letter is the engine's family.
- The next two numbers identify the engine's displacement (or revision before 1989)
- The fifth character is an identifier to mark revisions, (ex: turbo, DOHC, Fuel Injection, etc)
All of Subaru's three cylinder engines are inline Four-stroke cycle design, Liquid Cooled.
- EF10: 997cc SOHC 2V, 55hp@5200 found in some Subaru Justy
- EF12: 1189cc SOHC 3V, 66-73hp found in the Subaru Justy
The EA was used from 1966 until 1994 in most models. It is a basic 2 valve per cylinder design with siamese ports.
- EA52: 977cc OHV, 55hp@6000 used in the 1966-1971 Subaru FF-1 Star
- EA61: 1088.8cc OHV, 62hp@6400 used in the 1970-1972 Subaru FF-1 Star and Subaru G
- EA62: 1267.5cc OHV, 80hp@6400 used in the 1971-1972 Subaru G
- EA63: 1362cc OHV, 58hp@5200 used in the 1973-1976 Subaru Leone
- EA71: 1595cc OHV, 67hp@5200 or 68@4800 used in the 1976-1987 Subaru Leone and 1978-1980 Subaru BRAT
- EA81: 1781cc OHV, 73hp@4800 used in the 1980-1984 Subaru Leone and 1981-1993 Subaru BRAT
- EA81T: 1781cc OHV Turbo, 95@4200 used in the 1983-1984 Subaru Leone and Subaru BRAT
- EA82: 1791cc SOHC, 84-97hp used in the Subaru Leone and Subaru XT
- EA82T: 1791cc SOHC, 115hp@5200 used in the Subaru Leone and Subaru XT
The EJ engine was introduced in the 1989 Subaru Legacy to replace the EA engines (although they were used in the Subaru Leone until 1994. These engines have four valved per cylinder and can be either SOHC or DOHC, the fifth digit is the only way to tell without seeing the engine.
- EJ15: 1483.4cc SOHC, 1990-1993 JDM Subaru Impreza
- EJ16: 90hp@5600 used in the 1993-2006 Subaru Impreza
- EJ18: 1820cc SOHC 110hp@5600 rpm used in the 1990-1996 Subaru Impreza and Euro and JDM Subaru Legacy
- EJ20: 1994.3cc, 220-280hp used on Most Turbo Models, (2002-2005 WRX in the United States)
- EJ22: 2212cc, 135-280hp used in the 1989-2001 Subaru Impreza and Subaru Legacy
- EJ25: 2457cc, 165-320hp found in Most Models 1995-Present
Subaru EN engine
The EN08 engine was used in the Fiori in Australia and some other markets. It was an inline 4-cylinder of 758cc, naturally aspirated with a single carburetor developing 31kW @ 6000rpm.
Subaru unveiled the world's first boxer diesel engine at the Geneva autoshow in 2007. This 2.0L DOHC engine has 163HP and 251b-ft and was released in Europe in 2008. It is scheduled to be released in North America in 2010. 
The EG engine was a direct replacement for the ER found in the Subaru XT sports car. Replacing it was the Subaru Alcyone SVX so Subaru needed a new engine. As with the ER27, Subaru took the EJ22 and stretched it two cylinders to make the new EG33. However, this four valve per cylinder engine was DOHC and valvetrain parts from the not yet released EJ25D.
Instead of stretching their current EJ20 as most might suspect, in 2000 Subaru did this family from the ground up. It is a totally new DOHC design using dual timing chains and coil-on-plug ignition. Nothing from these engines are interchangeable with any other Subaru engine as in the past. The EZ36 was introduced in 2008 to help the Tribeca's sluggish performance. It is a bored and stroked version of the EZ30.
- EZ30: 2999.6cc DOHC, 212-250hp found in 2000+ Subaru Outback H6, Legacy 3.0R, and Subaru Tribeca
- EZ36: 3564.3cc DOHC, 256@6000rpm 247lb-ft@4400rpm found in the 2008 Subaru Tribeca
Engine specifications EZ30
Type: flat-6, aluminum block and heads
Bore x stroke: 3.51 x 3.15 in, 89.2 x 80.0 mm
Displacement: 183 cu in, 3000 cc
Compression ratio: 10.7:1
Fuel-delivery system: port injection
Valve gear: chain-driven double overhead cams, 4 valves per cylinder, hydraulic lifters, variable intake- and exhaust-valve timing and lift
Power (SAE net): 256 bhp (191 kW) @ 6000 rpm
Torque (SAE net): 247 lb·ft (335 N·m) @ 4400 rpm
Redline: 7000 rpm
- Boxer Diesel