Subaru WRX Engine Guide: EJ205, EJ255, EJ257, FA20, and FA24

Identify the engine in a Subaru WRX or STI, compare the EJ205, EJ255, EJ257, FA20DIT, and FA24DIT, and find the right reliability, maintenance, and diagnostic guide.

White 2022 Subaru WRX viewed from the front and side
A 2022 Subaru WRX from the first model year of the FA24DIT-powered VB generation. Photo: Charles, CC BY 2.0.

The Subaru WRX has used several turbocharged boxer engines, and the engine under the hood changes what needs attention. A 2002 US-market WRX has an EJ205, a 2015 WRX has an FA20DIT, and a 2015 WRX STI has an EJ257 even though the two cars share a model year.

Quick answer: US-market WRX engines fall into four main groups: the EJ205 in the 2002-2005 WRX, EJ255 in the 2006-2014 WRX, FA20DIT in the 2015-2021 WRX, and FA24DIT in the 2022+ WRX. The US-market WRX STI used the EJ257 from 2004 through 2021. Imported and engine-swapped cars must be identified by engine code and installed hardware rather than the chassis year alone.

Use this page to identify the engine family and choose the right detailed guide. For a broad model-year and used-car comparison, go to the Subaru WRX reliability guide.

On this page
  1. Subaru WRX engine specs by generation
  2. How to identify your WRX engine
  3. What defines a Subaru WRX engine?
  4. EJ205: 2002 2005 WRX
  5. EJ255: 2006 2014 WRX
  6. EJ257: 2004 2021 WRX STI
  7. FA20DIT: 2015 2021 WRX
  8. FA24DIT: 2022+ WRX
  9. EJ vs. FA WRX engines
  10. WRX vs. STI engine differences
  11. Which Subaru WRX engine is best?
  12. Where to go for a WRX engine problem
  13. WRX engine maintenance by family
  14. Buying a replacement WRX engine
  15. Subaru WRX Engine FAQ
  16. Sources and further reading

Subaru WRX engine specs by generation

US-market model Engine Displacement Factory output Fuel system Cam drive Detailed guide
2002-2005 WRX EJ205 2.0 liters 227 hp and 217 lb-ft Port injection Timing belt Subaru EJ205 engine guide
2006-2014 WRX EJ255 2.5 liters Varies by model year; 224-265 hp Port injection Timing belt Subaru EJ25 engine guide
2004-2021 WRX STI EJ257 2.5 liters Varies by model year; 293-310 hp Port injection Timing belt Subaru EJ25 engine guide
2015-2021 WRX FA20DIT 2.0 liters 268 hp and 258 lb-ft Direct injection Timing chain Subaru FA20 engine guide
2022+ WRX FA24DIT 2.4 liters 271 hp and 258 lb-ft Direct injection Timing chain Subaru FA24 engine guide

These applications describe US-market cars. Subaru used other EJ and FA variants in Japan, Europe, Australia, and other markets. A swapped engine may also have a short block, cylinder heads, turbo, intake, wiring, or ECU from a different application.

The output figures are Subaru’s factory crankshaft ratings, not chassis-dyno results. EJ255 and EJ257 output changed across model years and special editions, so use the specifications for the exact car when comparing parts or calibrations.

How to identify your WRX engine

Start with the VIN, model year, market, and trim. WRX and WRX STI versions from the same year can use different engines, and a used car may no longer have its original long block.

Check:

  1. The emissions label under the hood and the engine-code markings on the block.
  2. The VIN and original equipment through Subaru’s owner or dealer resources.
  3. Repair invoices for a replacement short block, long block, or imported engine.
  4. The intake, turbo, intercooler, fuel system, wiring, and ECU calibration when an engine swap is suspected.

Confirm the installed engine and application-specific part number before ordering internal parts, timing components, spark plugs, sensors, or a replacement engine.

Listings may use FA20F or FA24F instead of FA20DIT or FA24DIT. Match the model, market, year, and part number when selecting parts or a replacement assembly.

What defines a Subaru WRX engine?

Every production WRX uses an intercooled, turbocharged, horizontally opposed four-cylinder engine. “Boxer” describes the flat cylinder layout: two cylinder banks face away from each other and the opposing pistons move horizontally.

Replacement compatibility also depends on the transmission, flywheel or torque converter, wiring, ECU, sensors, and emissions equipment.

EJ205: 2002-2005 WRX

The EJ205 is the 2.0-liter turbocharged engine found in the first US-market WRX models. It uses port fuel injection and a timing belt. On surviving cars, inspect hoses, seals, wiring, turbo plumbing, cooling components, engine mounts, and previous modifications.

Before buying an EJ205 car, verify timing-belt history, oil level, coolant condition, compression balance, turbo condition, tune and hardware compatibility, and the five-speed transmission. If the engine has been replaced, identify whether it remains an EJ205 or uses a mixed EJ configuration.

The Subaru EJ205 engine guide covers specifications, USDM and JDM differences, reliability, identification, and replacement-engine compatibility. The Subaru EJ25 engine guide begins with the later 2.5-liter WRX and STI engines.

EJ255: 2006-2014 WRX

The 2.5-liter EJ255 replaced the EJ205 in the US-market WRX for 2006. It retained port injection and a timing belt. Factory hardware and calibrations changed across the 2006-2014 run, so turbo, intercooler, cylinder-head, sensor, and ECU details should be checked by model year.

Useful EJ255 inspection areas include:

  • Timing-belt and related component history.
  • Oil level, oil leaks, and signs of oil consumption.
  • Cooling-system condition and any overheating history.
  • Compression or leakdown results when symptoms, modifications, or missing records justify testing.
  • Tune compatibility with the intake, boost-control hardware, turbo, intercooler, exhaust, and fuel system.

For piston ringland symptoms and diagnosis, use the EJ255 and EJ257 ringland-failure guide. The broader EJ25 engine guide covers EJ255 design, applications, and specifications.

EJ257: 2004-2021 WRX STI

The US-market WRX STI used the 2.5-liter EJ257 through its final 2021 model year. Compared with the EJ255 WRX package, its cylinder heads, turbo system, intercooler, calibration, and internal revisions differ by application and year.

The EJ257 is paired with the STI six-speed and Driver Controlled Center Differential system. The WRX vs. STI comparison details the other drivetrain, brake, and chassis differences.

EJ25 engine bay in a Subaru Impreza WRX STI
EJ25 engine bay in a North American Subaru Impreza WRX STI. Photo: atzerok, CC BY-SA 2.0. Cropped and resized.

For focused engine diagnosis:

FA20DIT: 2015-2021 WRX

The VA-generation WRX moved to the 2.0-liter FA20DIT while the contemporary STI retained the EJ257. The FA20DIT uses direct injection, a timing chain, and a twin-scroll turbocharger. Its intake, exhaust, fuel, and calibration requirements differ from the EJ engines.

Direct injection means fuel does not wash the backs of the intake valves. Deposits can develop, but rough idle or a misfire should still be diagnosed before intake-valve cleaning is scheduled. Ignition faults, intake leaks, boost leaks, fuel quality, and calibration can produce overlapping symptoms.

Continue with:

FA24DIT: 2022+ WRX

The VB WRX uses the 2.4-liter FA24DIT with direct injection and a timing chain. Its intake, turbo system, electronics, transmission programming, parts, and calibrations are platform-specific rather than interchangeable with the FA20DIT.

FA24F engine bay in a Japanese-market VB Subaru WRX S4
FA24F engine bay in a Japanese-market VB WRX S4 STI Sport R EX. Photo: Tokumeigakarinoaoshima, CC BY-SA 4.0. Cropped and resized.

Long-term evidence is still developing compared with the EJ and FA20DIT. Current owners should prioritize oil-level history, cooling and charge-air plumbing, ignition condition, matching fuel and calibration, and complete service records.

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EJ vs. FA WRX engines

Difference EJ205, EJ255, and EJ257 FA20DIT and FA24DIT
Fuel delivery Port injection Direct injection
Cam drive Timing belt Timing chain
Intake-valve deposits Fuel passes across the intake valves Fuel is injected directly into the cylinder, so intake deposits require separate consideration
Tuning and parts Deep aftermarket, but many revisions and mixed builds exist Newer ECU and direct-injection systems require platform-specific parts and calibration
Used-car priority Age, timing service, oiling, cooling, engine health, and modification history Oil history, deposits, boost plumbing, ignition, calibration, heat, and modification history

Condition and configuration change the risk within each engine family. A documented stock EJ257 differs from an unknown mixed-engine build, and a factory-calibrated FA20DIT differs from one with undocumented airflow changes.

WRX vs. STI engine differences

For 2015-2021, the WRX and WRX STI use different engine families:

Model Engine Main distinction
2015-2021 WRX FA20DIT 2.0-liter direct-injection engine with a twin-scroll turbo
2015-2021 WRX STI EJ257 2.5-liter port-injected EJ engine paired with the STI drivetrain

Select engine internals, turbo and exhaust parts, intakes, intercoolers, fuel components, maintenance parts, and tuning maps for the specific WRX or STI application.

Which Subaru WRX engine is best?

Choose by use case:

  • Older analog WRX: the EJ205 and EJ255 provide the classic early-WRX experience, but condition and previous work dominate the purchase.
  • STI drivetrain and EJ platform: the EJ257 is the relevant engine, paired with the STI-specific transmission and AWD hardware.
  • VA daily driver: the FA20DIT combines direct injection, a broad torque curve, and extensive aftermarket support.
  • Current WRX platform: the FA24DIT provides more displacement and a newer chassis, with less high-mileage history available.

For a used car, compare cold-start behavior, oil and coolant condition, service records, installed hardware, tune documentation, compression or leakdown results when warranted, and evidence of overheating or repeated track use.

Where to go for a WRX engine problem

Question or symptom Start here
Broad reliability or used-car inspection Subaru WRX reliability by year
EJ25 specifications and variants Subaru EJ25 engine guide
Suspected EJ piston or compression problem EJ255/EJ257 ringland failure
EJ257 knock or bearing concern EJ257 rod-bearing failure
FA20DIT rough running or reliability question FA20DIT common problems
FA24DIT reliability or oil concern FA24DIT common problems
Hissing, inconsistent boost, underboost, or fuel-trim changes WRX boost-leak guide
FA20DIT intake-valve deposits WRX walnut-blasting guide
Oil vapor in the intake or AOS fitment WRX AOS and catch-can guide
Service intervals WRX maintenance schedule
Routine and repair budgeting WRX maintenance cost
Planning engine and supporting modifications Subaru WRX stages and upgrade paths
Choosing between remote and dyno tuning WRX e-tune vs. dyno tune

WRX engine maintenance by family

For every WRX, use the maintenance booklet for the exact model year, market, engine, and transmission. The main engine-family difference is timing service: EJ engines use a timing belt, while the FA20DIT and FA24DIT use timing chains.

The WRX maintenance schedule organizes service by EJ, VA, and VB platform. The WRX maintenance-cost guide separates routine service from the repairs that become more relevant as each generation ages.

Modified cars need the hardware and ECU calibration reviewed together. Record the intake, turbo inlet, boost-control system, intercooler, exhaust, injectors or fuel system, sensors, fuel, and calibration source. Resolve any parts-list and map mismatch before using boost or knock data to judge the engine.

Buying a replacement WRX engine

Engine and motor are used interchangeably in replacement listings, but the included assembly can range from a bare short block to a complete engine with turbo and accessories. Before pricing a WRX engine replacement, confirm:

  • The full engine code and donor market.
  • Compatible cylinder heads, sensors, cam and crank triggers, and wiring.
  • Intake, exhaust, turbo, intercooler, and accessory compatibility.
  • Transmission and flywheel or torque-converter compatibility.
  • ECU, immobilizer, and calibration requirements.
  • Compression and leakdown results for a used complete engine.
  • What the seller’s warranty requires before startup.

A low-mileage imported engine can still require wiring, sensor, intake, turbo, emissions, or calibration changes. Price the complete installation rather than the bare engine alone.

Subaru WRX Engine FAQ

What engine does a Subaru WRX have?

US-market WRX models used the EJ205 for 2002-2005, EJ255 for 2006-2014, FA20DIT for 2015-2021, and FA24DIT for 2022 and newer. US-market WRX STI models used the EJ257 from 2004 through 2021. Confirm imported and swapped cars by engine code.

Are all Subaru WRX engines turbocharged?

Yes. Production WRX and WRX STI models use turbocharged engines. Other Impreza models have used naturally aspirated engines, so an Impreza badge alone does not identify a WRX engine.

Does the WRX have a boxer engine?

Yes. WRX engines use Subaru horizontally opposed four-cylinder architecture. The EJ and FA families differ in displacement, fuel system, timing drive, turbo layout, and electronics.

How much horsepower does a Subaru WRX engine make?

US-market WRX ratings include 227 horsepower for the 2002-2005 EJ205, 224 to 265 horsepower for the EJ255 depending on model year, 268 horsepower for the FA20DIT, and 271 horsepower for the FA24DIT. EJ257 WRX STI models range from 293 to 310 horsepower outside limited special editions.

Is the WRX STI engine the same as the WRX engine?

The clearest difference is 2015-2021: the WRX uses the FA20DIT, while the WRX STI uses the EJ257. Select parts and tuning maps for the exact model and engine.

Does a WRX have a timing belt or timing chain?

EJ-powered WRX and STI engines use a timing belt. The FA20DIT and FA24DIT use timing chains.

What is the difference between the FA20 and FA24 WRX engines?

The FA20DIT is a 2.0-liter engine used in the 2015-2021 WRX. The FA24DIT is a 2.4-liter engine used in the 2022 and newer WRX. They have different displacement, hardware, electronics, calibration, and fitment.

Which WRX engine is most reliable?

Judge an individual car from its service history, oil and cooling records, modifications, calibration, previous use, and prior repairs. These factors vary substantially between cars with the same engine.

Can I install a different WRX engine in my car?

A swap must account for the cylinder heads, sensors, wiring, ECU and immobilizer, turbo plumbing, fuel system, exhaust, transmission, emissions equipment, and calibration.

Sources and further reading