Subaru Six-cylinder Engines - Wikipedia

Created as a refined luxury engine with improved power over the EA82T, Subaru introduced the ER27 engine in November 1985 for the Subaru ACX-II concept car, shown at the Tokyo Motor Show and billed as the 'concept car of the near future.'[2] The concept went into production as the Subaru Alcyone VX (Subaru XT6 in North America) in August 1987,[3] the exclusive application for the ER27.

When the ER27 was introduced, it was the only water-cooled flat-6 automobile engine on the market.[4] The ER27 designation was the first time Subaru incorporated the engine's displacement into the engine designation and all subsequent engine codes have retained this nomenclature.

Design

Like the EA series engines, the ER27 engine featured two valves per cylinder heads (six valves per cylinder head) with hydraulic lash adjusters and the ER27 and EA engines shared the same bore, stroke, and spacing. While recognised as bearing many similarities to the Subaru EA82 engine, there are numerous differences in design between the two engines and a large portion of parts are unique to the ER27. For instance, the oil and water pumps are unique to the ER27,[5][6] sharing similar bolt patterns and design to the EA82,[7][8] but being of a higher flow in both cases.[9]

The intake manifold uses a two-piece design with a lower section bolting to the heads containing the coolant bridge, injectors and various vacuum lines.[10] The upper intake manifold then bolts to the lower section and is unlike the EA82 or EJ22 "spider" manifold designs in that there is no central plenum chamber.[11]

The valve timing system is belt-drive using two individual timing belts, curiously one belt uses a spring tensioner (like the EA82) whilst the other uses a hydraulic tensioner (like the EJ22).[12]

Both JDM and USDM versions of the ER27 used multi-point electronic fuel injection. In North America, the ER27 was slightly derated to 145 hp (108 kW; 147 PS) at 5,200 RPM and 156 ft⋅lb (212 N⋅m) at 4,000 RPM.[4]