The SUBARU EJ207 is a 1,994 cc, flat-four turbocharged petrol engine produced between 1996 and 2006. It features DOHC, 16-valve configuration with AVCS (Active Valve Control System) on the intake cam, delivering 184 kW (250 PS) and 318 Nm of torque in JDM STI applications. Its horizontally opposed layout provides low center of gravity and balanced performance across high-performance platforms.
Fitted to the Impreza WRX STI, the EJ207 was engineered for motorsport-derived performance and all-weather traction in Subaru's flagship sports sedan. Emissions compliance was achieved through exhaust gas recirculation (EGR), catalytic converter, and closed-loop fuel control, enabling Euro 2 and US Tier 1 standards depending on market.
One documented concern is head gasket degradation under sustained high boost or improper cooling system maintenance. This issue, highlighted in Subaru Service Information Bulletin 98-05-02, often led to coolant loss and compression leakage. In response, Subaru issued revised cylinder head machining procedures and recommended use of multi-layer steel (MLS) gaskets during repairs.
Production years 1996–2006 meet Euro 2 and US Tier 1 emissions standards depending on market (VCA UK Type Approval #VCA/EMS/3476).
The SUBARU EJ207 is a 1,994 cc flat-four turbocharged petrol engine engineered for high-performance applications (1996–2006). It combines Subaru's signature boxer layout with DOHC valvetrain and AVCS technology to deliver refined power delivery and mechanical balance. Designed to meet evolving emissions standards, it balances track capability with road legality.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,994 cc | |
| Fuel type | Petrol | |
| Configuration | Flat-4, DOHC, 16-valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 86.0 mm × 86.0 mm | |
| Power output | 184 kW (250 PS) @ 6,500 rpm | |
| Torque | 318 Nm @ 4,000 rpm | |
| Fuel system | Multi-point fuel injection (MPFI) with AVCS | |
| Emissions standard | Euro 2, US Tier 1 (market-dependent) | |
| Compression ratio | 8.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | IHI VF28 ball-bearing turbo | |
| Timing system | Double-row timing chain | |
| Oil type | SAE 5W-30 or 10W-30 (API SL) | |
| Dry weight | 132 kg |
The turbocharged flat-four design provides exceptional balance and high-RPM power ideal for spirited driving but requires strict adherence to 15,000 km oil change intervals to maintain chain longevity and turbo health. Use of API SL-rated oil is critical due to its formulation supporting hydraulic lifters and timing chain lubrication. Cooling system maintenance is essential to prevent overheating and head gasket failure; use of correct coolant mix (HOAT-based) and regular flushes are recommended. Pre-1998 models should follow revised head gasket installation procedures per Subaru SIB 98-05-02 if experiencing compression loss. Engines used in high-mileage or boosted applications require valve clearance inspection every 60,000 km.
Oil Specs: Requires API SL specification oils (Subaru Owner's Manual 96-06). Non-detergent or lower-grade oils increase wear risk.
Emissions: Euro 2 and US Tier 1 certification applies to production years (1996–2006) (VCA Type Approval #VCA/EMS/3476). Market-specific variations exist.
Power Ratings: Measured under SAE J1349 standards. Output consistent across fuel qualities meeting ASTM D4814.
Subaru Technical Information System (TIS): Docs A16000, A16300, SIB 98-05-02
Subaru EPC and Parts Catalogue: E-EJ207 Series
VCA Type Approval Database (VCA/EMS/3476)
SAE International: J1349 Engine Power Certification Standards
The SUBARU EJ207 was used across SUBARU's Impreza WRX STI platform with longitudinal mounting. This engine received platform-specific adaptations-higher-boost turbos in later revisions-and from 2006 the facelifted Impreza LCI adopted the EJ25 variant with larger displacement, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the left-side engine block near the transmission bellhousing (Subaru TIS A16900). The 5th digit of the VIN indicates engine family ('E' for EJ series). All EJ207 units have silver valve covers with "EJ20" branding and AVCS solenoid on the intake cam cover. Critical differentiation from EJ25: Original EJ207 uses 2.0L displacement with smaller bore, while EJ25 features 2.5L and revised intake manifold. Service parts require production date verification - head gaskets before 06/1998 are prone to failure and should be replaced with post-revision MLS units per Subaru SIB 98-05-02.
The EJ207's primary reliability risk is head gasket degradation on pre-1998 builds, with elevated incidence in mixed driving conditions. Internal Subaru quality reports from 1997 indicated a significant number of pre-upgrade heads requiring replacement before 100,000 km, while UK DVSA records show coolant-related failures were common in neglected examples. Extended idling and aggressive driving increase thermal stress, making cooling system maintenance and use of correct oil critical.
Analysis derived from Subaru technical bulletins (1996–2006) and UK DVSA failure statistics (2007–2017). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about SUBARU EJ207.
Comprehensive technical documentation and regulatory references
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EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
WLTP and RDE testing procedures for emissions certification.
GOV.UK: Vehicle Approval
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
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