Subaru EJ20T Specifications
| Engine Model: Subaru EJ20T |
| Engine Type: 4-cycle 4-cylinder DOHC 16-valve turbocharged liquid-cooled gasoline |
| Total Displacement: 121.7 cu.in (1.99 L) |
| Rated Engine Power: 227-280 Hp (168-206 kW) at 6000 rpm |
| Fuel System Type: Sequential multi-point electronic fuel injection (MPFI) |
____________________________________________________________________________________
The Subaru EJ20T is a 2.0-liter,
horizontally-opposed (flat-four), dual overhead camshaft (DOHC),
16-valve, turbocharged gasoline engine. It is the foundational
turbocharged variant of the legendary EJ20 series, which became
synonymous with Subaru's performance identity, particularly through the
Impreza WRX and WRX STI. Introduced in the early 1990s, the EJ20T
established the blueprint for Subaru's turbo boxer engines: a robust
semi-closed deck block, a turbocharger mounted low for a low center of
gravity, and an intercooler to manage charge temperatures.
Early versions (1990s) featured a simple, responsive turbocharger and
hydraulic lash adjusters, while later iterations evolved with
twin-scroll turbos, variable valve timing (AVCS), and more sophisticated
engine management. The engine is renowned for its distinctive boxer
rumble, strong mid-range torque, and immense tuning potential. It is
celebrated for its durability when well-maintained and properly tuned,
but also known for specific failure points if neglected or pushed beyond
its limits with inadequate supporting mods. The EJ20T is an icon of the
turbocharged era, powering Subaru's rally-bred road cars and creating a
global enthusiast community.
Engine Family / Model: Subaru EJ series (Flat-Four), Model EJ20T
(encompasses multiple codes: EJ20G, EJ20K, EJ206, EJ207, EJ208, etc.,
depending on market and year).
Engine Type: Horizontally-opposed four-cylinder (flat-four, boxer),
longitudinally front-mounted, four-stroke cycle, water-cooled,
turbocharged and intercooled gasoline engine.
Fuel Management: Sequential Multi-Point Fuel Injection (MPFI). Early:
Hitachi or JECS ECU. Later: Subaru-specific ECU, often with
drive-by-wire.
Aspiration: Forced induction via a turbocharger (IHI, Mitsubishi, or
Hitachi) and an intercooler (top-mounted on many models, front-mounted
on others).
Bore: 92.0 mm / 3.622 inches. Stroke: 75.0 mm / 2.953 inches.
Displacement: 1,994 cc / 121.7 cubic inches.
Compression Ratio: Varies by version: Early high-output: 8.0:1. Later
versions (e.g., USDM WRX): 8.5:1. STI versions: 8.2:1. Firing Order:
1-3-2-4. (Cylinders: Left bank 1-2; Right bank 3-4. Front cylinders are
1 and 3). Rotation Direction (from front/crank pulley): Clockwise.
Maximum Power Output: Early WRX (1992): 177 kW (240 PS).
USDM WRX (2002-2005): 168 kW (227 hp).
JDM STI Version 7 (EJ207): 206 kW (280 PS).
Maximum Torque: 290-400 Nm (214-295 lb-ft) depending on version and
boost.
Boost Pressure: Ranges from 0.7 bar (10 psi) to 1.2 bar (17.4 psi)
stock.
Redline: 6,500-8,000 rpm (STI models).
Fuel Requirement: Premium unleaded gasoline (98 RON / 93 AKI) essential.
Construction: Cast aluminum alloy. Critical Distinction: Turbo EJ20s use
a semi-closed deck or (in STI Spec C/RA) closed deck block design. This
provides much greater rigidity and resistance to cylinder wall flex
under high boost compared to the open-deck NA blocks.
Cylinder Bores: Cast-in iron liners (dry liners). The closed/semi-closed
deck reinforces the upper cylinder area. Crankshaft: Forged steel on
high-performance versions (EJ207 STI), nodular cast iron on others.
Supported by five main bearings.
Main Bearings: Steel-backed, aluminum alloy shell bearings.
Pistons: Cast hypereutectic aluminum on standard turbo models. Forged
aluminum pistons on high-performance variants (EJ207 STI). Feature oil
squirt jets for cooling.
Connecting Rods: Forged steel on performance versions, powdered metal on
standard turbos. STI models use stronger I-beam forged rods.
Oil Pan: Cast aluminum or stamped steel with baffles.
Construction: aluminum alloy, one per bank. Early heads have straight
ports; later STI heads have large, tumble-generating ports.
Valve Arrangement: Dual Overhead Camshafts (DOHC) per bank (four total).
Early heads (EJ20G/K) use hydraulic lash adjusters (HLAs). Later
performance heads (EJ207) use solid shim-under-bucket adjusters for
high-RPM stability.
Valvetrain: Direct-acting on buckets. Performance versions have
sodium-filled exhaust valves.
Combustion Chamber: Pent-roof design.
Valve Angles: Variable. Early: 45-degree intake/40-degree exhaust. Later
"big port" heads: 45-degree on both. Valve Diameter: Intake: 33.5-36.0
mm. Exhaust: 29.5-31.0 mm.
Valve Clearance: HLA heads: no adjustment. Shim-under-bucket: requires
shim replacement. Clearance: Intake: 0.15-0.25 mm; Exhaust: 0.25-0.35
mm.
Camshaft Drive: Single toothed rubber timing belt driving all four
camshafts, water pump, and oil pump. Uses hydraulic tensioners.
Interference engine.
Injection System: Sequential MPFI. Early: side-feed injectors. Later
(post-2000): top-feed injectors.
Engine Management: Varies: Early JDM: Hitachi. USDM WRX: Subaru/Denso.
STI models: more advanced ECU with finer control.
Fuel Injectors: Flow rates vary: 380cc/min (early) to 550cc/min (later
STI). Top-feed design allows for easier upgrades. Fuel Pump: In-tank
electric pump, upgraded on performance models.
Turbocharger: Early: IHI VF series (e.g., VF23, VF28, VF30). USDM WRX:
Mitsubishi TD04L. Later STI: IHI twin-scroll (VF36/37, etc.).
Intercooler: Top-mounted (TMIC) on most Impreza/WRX. Front-mounted
(FMIC) on some special editions and aftermarket. Boost Control:
Electronic solenoid controlled by ECU (early used a bleed valve).
Type: Full-pressure, wet-sump. Known for oiling issues under high-g
cornering; aftermarket baffled pans are common. Oil Pump: Gerotor
(trochoid) type, driven by the crankshaft. High-flow 12mm pumps on STI.
Oil Filter: Standard screw-on canister, mounted vertically at front.
Oil Cooler: Optional on some models, standard on STI (oil-to-water).
Oil Capacity: 4.2-4.8 liters (4.4-5.1 US quarts) including filter.
Recommended Oil: High-quality synthetic 5W-30 or 10W-40 (API SN/SP).
Critical due to turbo heat.
Type: Pressurized, with separate turbo coolant lines.
Water Pump: Impeller type, driven by timing belt.
Thermostat: 76°C (169°F) or 82°C (180°F) opening.
Radiator: aluminum core. STI models have a larger, dual-core radiator.
Coolant Capacity: 7.5 liters (8 US quarts).
Coolant: Ethylene-glycol, Subaru Super Coolant recommended.
Electrical: 12V. Coil-on-plug ignition on later models (GD/GG chassis),
coil packs with wires earlier.
Ignition: Direct ignition (coil-on-plug) post-2000. Earlier models used
a distributor or separate igniter.
Spark Plugs: Iridium or platinum. One heat range colder than NA often
used. Gap: 0.7-0.8 mm.
Emissions: EGR, PCV, catalytic converter(s). Upstream and downstream O2
sensors.
Length: 650 mm (25.6 in).
Width: 800 mm (31.5 in) wide due to heads and turbo.
Height: 600 mm (23.6 in).
Weight: 150-160 kg (330-353 lbs) dressed.
Oil Changes: Every 5,000 km (3,100 mi) with full synthetic.
Timing Belt: Replace every 100,000 km (62,000 mi) or 5-7 years. Include
idlers and tensioner.
Spark Plugs: Replace every 60,000 km (37,000 mi). Iridium recommended.
Coolant: Replace every 48 months or 100,000 km.
Fuel Filter: Every 60,000 km.
Air Filter: Every 30,000 km.
Valve Clearance (shim type): Check every 100,000 km.
PCV Valve: Replace every 60,000 km.
Turbo Care: Allow cool-down idle after hard driving. Monitor for shaft
play.
Cylinder Head Bolts (EJ20 Phase 2): TTY. Step 1: 29 Nm (22 lb-ft). Step
2: Tighten 90°. Step 3: Loosen completely. Step 4: 29 Nm. Step 5:
Tighten 90°. New bolts mandatory.
Main Bearing Cap: 54-59 Nm (40-44 lb-ft).
Connecting Rod Cap: 49-54 Nm (36-40 lb-ft) + 90° turn (STI forged).
Others: torque only, 50 Nm.
Crankshaft Pulley Bolt: 177-186 Nm (131-137 lb-ft).
Cam Sprocket Bolt: 59-78 Nm (44-58 lb-ft).
Spark Plugs: 18-22 Nm (13-16 lb-ft).
Oil Pan Bolts: 8-12 Nm (6-9 lb-ft).
Valve Cover: 8-10 Nm (6-7 lb-ft).
Intake Manifold: 18-22 Nm (13-16 lb-ft).
Exhaust Manifold/Uppipe: 30-35 Nm (22-26 lb-ft).
Turbo to Uppipe/Downpipe: 40-50 Nm (30-37 lb-ft).
The EJ20T powered nearly all of Subaru's performance models from
1989-2010+ in various forms: Subaru Legacy (1989-2000s): Turbo models
(GT, RS, B4). Subaru Impreza WRX (1992-2007 GD/GG): All markets. The
defining car. Subaru Impreza WRX STI (1994-2007): JDM, USDM (2004+),
EDM. Uses high-spec EJ207/257. Subaru Forester (SF/SG Turbo):
Performance SUV variant. Subaru Outback (Turbo models). Subaru Levorg
(early JDM turbo).
The EJ20T was gradually replaced by the 2.5L EJ255/EJ257 in many markets
(USDM) but continued in JDM STIs (EJ207) and other markets well into the
2010s. It is the heart of the Subaru rally and tuning legacy.
____________________________________________________________________________________
| Car Engines Technical Specifications |
| Small Engines Technical Specifications |
| Industrial Engines Technical Specifications |
| Outboard Engines Technical Specifications |
