EJ204 Subaru EngineThe Subaru EJ204 was a 2.0litre horizontallyopposed (or 'boxer') fourcylinder petrol engine with double overhead camshafts. The naturally aspirated E204 engine was initially introduced in the 2005 Subaru GD/GG Impreza and 2006 Subaru BL/BP Liberty as a more powerful alternative to the single overhead cam EJ202 engine, but effectively replaced the EJ202 when the GE/GH Impreza was released inFB20 Subaru EngineSubaru's FB20 was a 2.0litre horizontallyopposed (or 'boxer') fourcylinder petrol engine. Effectively replacing the EJ204 engine, the FB20 engine was a member of Subaru's third generation 'FB' boxer engine family which also included the FB25, FA20D, FA20E and FA20F engines.The FB20 engine first offered in Australia in