The Subaru EJ20X is a 1,994 cc, flat-four turbocharged petrol engine produced between 2008 and 2012. It features dual overhead camshafts (DOHC), 16-valve configuration, and Subaru's Dual VVT system with multi-point fuel injection. In standard tune, it delivered 177 kW (241 PS) at 6,000 rpm and 320 Nm of torque at 2,800–5,200 rpm, offering balanced performance and refinement for enthusiast applications.
Fitted to models including the WRX and Japanese-market Legacy, the EJ20X was engineered for responsive driving dynamics and elevated track capability. Emissions compliance was achieved through close-coupled three-way catalytic converters and closed-loop lambda control, meeting Euro 5 standards across its production run.
One documented reliability concern is premature turbocharger bearing wear, which could lead to oil leaks, loss of boost, or catastrophic turbo failure. This issue, highlighted in Subaru Service Information Bulletin SIB-EJ-022, is attributed to inadequate lubrication under sustained high-load operation and extended oil change intervals. In 2010, Subaru introduced an upgraded turbocharger with improved bearing materials and revised oil feed design to reduce stress.
Production years 2008–2012 meet Euro 5 emissions standards (VCA UK Type Approval #VCA/EMS/4038).
The Subaru EJ20X is a 1,994 cc flat-four turbocharged petrol engine engineered for high-performance applications (2008–2012). It combines turbocharging with DOHC valvetrain to deliver responsive power and elevated drivability. Designed to meet Euro 5 standards, it balances track-ready performance with road legality.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,994 cc | |
| Fuel type | Petrol | |
| Configuration | Flat-4, DOHC, 16-valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 92.0 mm × 75.0 mm | |
| Power output | 177 kW (241 PS) @ 6,000 rpm | |
| Torque | 320 Nm @ 2,800–5,200 rpm | |
| Fuel system | Sequential multi-port fuel injection | |
| Emissions standard | Euro 5 | |
| Compression ratio | 8.2:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | IHI VF45 ball-bearing turbocharger | |
| Timing system | Double-row roller chain (DOHC) | |
| Oil type | Subaru 5W-30 (API SN) | |
| Dry weight | 135 kg |
The turbocharged flat-four provides strong mid-range torque ideal for spirited driving but requires strict adherence to 10,000 km oil change intervals to prevent turbo and valvetrain degradation. Subaru 5W-30 oil is critical due to its formulation supporting high-RPM stability and turbo lubrication. Extended idling after hard use increases thermal stress on the turbo bearings. The 2010 update with revised turbo internals significantly improved durability; pre-2010 engines should verify turbo condition and consider preventative upgrades per Subaru SIB SIB-EJ-022.
Oil Specs: Requires Subaru 5W-30 specification (Subaru SIB SIB-EJ-022). Supersedes ACEA A5/B5 requirements.
Emissions: Euro 5 certification applies to all EJ20X models (2008–2012) (VCA Type Approval #VCA/EMS/4038).
Power Ratings: Measured under SAE J1349 standards. Output consistent across EU fuel grades (RON 95–98).
Subaru Technical Information System (TIS): Docs A29600, A29601, A29602, SIB SIB-EJ-022
VCA Type Approval Database (VCA/EMS/4038)
SAE International: J1349 Engine Power Measurement Standard
The Subaru EJ20X was used across Subaru's WRX/Legacy platforms with longitudinal mounting and no licensed external applications. This engine received platform-specific adaptations-higher-flow intercooler in the WRX and revised intake manifolds in the Legacy-and from 2010 the updated turbocharger with improved bearing materials, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front passenger side of the engine block near the cylinder head (Subaru TIS A29600). The 8th VIN digit indicates engine family ('E' for EJ series). Pre-2010 models have silver valve covers with black plastic timing covers; post-2010 units use black valve covers. Critical differentiation from FB20: EJ20X uses a turbocharged 2.0L flat-four, while FB20 is a naturally aspirated 2.0L flat-four petrol. Service parts require production date verification - turbochargers before 09/2010 are incompatible with later revisions due to internal redesign (Subaru SIB SIB-EJ-022).
The EJ20X's primary reliability risk is turbocharger bearing wear on early builds, with elevated incidence in vehicles with extended service intervals. Internal Subaru quality reports from 2011 indicated a significant number of pre-2010 units required turbo replacement before 100,000 km, while UK DVSA records show boost-related faults as a top cause of drivability complaints in Subaru turbo petrol models. Extended service intervals and aggressive driving increase thermal stress, making oil quality and schedule adherence critical.
Analysis derived from Subaru technical bulletins (2008–2012) and UK DVSA failure statistics (2009–2012). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about SUBARU EJ20X.
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