What is EJ20?
Subaru's 2.0-litre turbocharged boxer engine, the heart of the Impreza WRX and STI and a rally and tuning icon.
The EJ20 is a 2.0-litre horizontally opposed (boxer) four-cylinder built by Subaru from 1989. In turbocharged form it powered the Impreza WRX and STI, becoming central to Subaru's rally success and its distinctive performance identity.
The boxer layout gives the EJ20 a low centre of gravity and a characteristic offbeat exhaust rumble, often amplified by unequal-length headers. Paired with Subaru's symmetrical all-wheel drive, the engine helped define the rally-bred road car formula.
The EJ20 is highly tunable and well supported by the aftermarket, though its ringland pistons and cooling demand careful tuning at high power. It powered World Rally Championship-winning cars and remains a beloved enthusiast engine, later succeeded by the FA20 family.