Catalogs
TorqueList Garage Reference Series

Volume 1 · Subaru

Engine
Reference Catalog

Factory specifications, architecture, key variants, engineering notes, racing history and the stories that made Subaru's most important engines matter.

Technical reference•Historical context•Builder notes•Print ready

Edition 1.0 · September 2026 · Published

Public preview · first 3 engine profiles unlocked

15

Detailed engine profiles

14/15

Commercially cleared photos

31

Source references

V1

7 engine families

Publication notice

Independent TorqueList reference

Independence

TorqueList is an independent automotive reference publication and is not affiliated with, sponsored by, endorsed by, or authorized by Subaru Corporation or any other vehicle or engine manufacturer.

Trademarks

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Copyright

© 2026 TorqueList. Original editorial text, compilation, selection, organization, layout, and TorqueList-created graphics are protected by copyright. Underlying facts, specifications, and manufacturer-identifying terms remain the property or factual subject matter of their respective owners.

Accuracy

Specifications can vary by model year, application, option code, market, and production revision. Verify critical service, purchasing, racing, and installation information against the exact factory documentation for the specific vehicle or engine before relying on it.

Media policy

Third-party photographs appear only when their commercial-use basis is recorded. Creator, source, and license information is retained with each approved image. Engines without an approved third-party photograph use TorqueList-owned original technical artwork.

Contents

Subaru Engine Reference — Volume 1

Profiles are organized by engine family and pull from the same published TorqueList Engine Library used by the web experience.

EA Boxer

3 profiles
Subaru EA521966–1969 core era
59.5 ci
Subaru EA81 1.81980–1994 family/application era
108.7 ci
Subaru EA82T1985–1994 core era
108.7 ci

EJ Boxer

2 profiles
Subaru EJ22E1989–2001 core era
135 ci
Subaru EJ25D1996–1999 U.S. core era
149.8 ci

EJ Turbo Boxer

3 profiles
Subaru EJ2051998–2007 family/application era
121.7 ci
Subaru EJ2071998–2020 performance era
121.7 ci
Subaru EJ2572004–2021 U.S. STI era
149.8 ci

EZ Boxer Six

2 profiles
Subaru EZ30R 3.02003–2009 core era
182.9 ci
Subaru EZ36D 3.62008–2019 core era
221.5 ci

FB New-Generation Boxer

1 profiles
Subaru FB25 2.52010–present family era
152.4 ci

FA Boxer

2 profiles
Subaru FA20D BRZ2012–2020 BRZ era
121.9 ci
Subaru FA24D BRZ 2.42022–present BRZ era
146 ci

FA DIT Boxer

2 profiles
Subaru FA20DIT 2.0 Turbo2012–2021 core era
121.9 ci
Subaru FA24F / FA24DIT 2.4 Turbo2018–present family era
146 ci
15/15 profiles include reference sources.
Every engine has artwork; rights-cleared real photos replace TorqueList original technical art as they are approved.
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01

TorqueList Technical Reference

EA Boxer

Full web profile

Subaru EA52

The 1.0-liter water-cooled boxer-four that launched Subaru's signature engine layout in the 1966 Subaru 1000.

TorqueList Original Technical Art

Subaru EA52

Boxer4 · N/A

0.977L
★

Why it matters

Key takeaway

The EA52 was the first Subaru production boxer engine, establishing the low, compact layout that became central to the brand's identity.

Engineering

Technical specification

Architecture
Horizontally opposed boxer four
Block
Aluminum
Cylinder heads
Aluminum
Valvetrain
OHV, 2 valves per cylinder
Aspiration
Naturally aspirated
Fuel delivery
Carbureted

The EA52 established Subaru’s production boxer-four formula with an aluminum horizontally opposed block, OHV valvetrain, and compact 977 cc displacement. Its low, flat layout reduced engine height and helped define the packaging philosophy Subaru would continue for decades.

Factory fitment

Notable applications

Subaru 1000

Strengths

  • Low center of gravity
  • Compact length
  • Historically important Subaru architecture

Watch-outs

  • Very limited modern parts support
  • Low output by modern standards
  • Specialist restoration knowledge required

Common upgrades

  • Period-correct carburetor tuning
  • Ignition modernization
  • Cooling-system restoration

Builder notes

Engineering notes worth knowing

01

977 cc / 59.5 cu in horizontally opposed four-cylinder.

02

Aluminum block and heads with OHV two-valve-per-cylinder architecture.

03

Naturally aspirated and carbureted.

04

Introduced in the Subaru 1000, the first Subaru production model built around the boxer layout.

History & context

The story behind the engine

Subaru’s modern engine identity starts with the EA52. The small engine itself was modest, but its flat-four layout created the low center of gravity and compact longitudinal packaging that became a brand trademark.

Legacy

The EA52 is the beginning of Subaru’s long production-boxer lineage and the architecture that set the direction for every major Subaru engine family that followed.

Verification

Reference sources

Subaru — 50th Anniversary of Boxer Engine

manufacturer history

SUBARU — Subaru 1000 EA52 factory specifications

manufacturer spec

TorqueList independent reference · Not an OEM publication or endorsement. Original TorqueList editorial and layout rights reserved.

02

TorqueList Technical Reference

EA Boxer

Full web profile

Subaru EA81 1.8

The durable pushrod 1.8-liter boxer used in GL, Brat and early Leone-era Subaru vehicles.

Subaru EA81 1.8 engine

Subaru EA81 1.8 enginePhoto: Ferjim · source

★

Why it matters

Key takeaway

The EA81 earned a durability reputation in early Subaru 4WD cars and pickups and remains one of the simplest classic Subaru boxer engines to service.

Engineering

Technical specification

Architecture
Horizontally opposed boxer four
Block
Aluminum
Cylinder heads
Aluminum
Valvetrain
OHV, 2 valves per cylinder
Aspiration
Naturally aspirated; turbocharged EA81T existed in limited applications
Fuel delivery
Carbureted; fuel injection/turbo in selected variants

The EA81 was a simple aluminum boxer four with pushrod OHV valvetrain and a 1.8-liter displacement. Its relatively short 2.638-inch stroke, low engine height, and straightforward construction made it durable and easy to service in early Subaru 4WD vehicles.

Factory fitment

Notable applications

Subaru GL/LeoneSubaru BratSubaru DLSubaru Touring Wagon

Strengths

  • Simple pushrod valvetrain
  • Good low-speed durability
  • Compact boxer packaging

Watch-outs

  • Limited airflow
  • Aging cooling and sealing systems
  • Performance parts are niche

Common upgrades

  • Weber carburetor conversion
  • Exhaust
  • Electronic ignition

Builder notes

Engineering notes worth knowing

01

1.781 L / 108.7 cu in with 3.622 x 2.638-inch bore and stroke.

02

Aluminum boxer four with OHV two-valve cylinder heads.

03

Naturally aspirated carbureted versions were most common; limited turbo and injected variants also existed.

04

Used in Leone/GL, BRAT, DL, and Touring Wagon applications.

History & context

The story behind the engine

The EA81 powered the era when Subaru’s four-wheel-drive cars and BRAT built the company’s rugged reputation. It was not sophisticated, but its simplicity matched the durable, practical personality of those early Subarus.

Legacy

The EA81 became one of the classic old-school Subaru engines, remembered for simple pushrod construction and long service life in early 4WD cars and pickups.

Verification

Reference sources

Subaru — Boxer engine history

manufacturer history

Motor-Car.net — Subaru EA81 specifications

technical reference

TorqueList independent reference · Not an OEM publication or endorsement. Original TorqueList editorial and layout rights reserved.

03

TorqueList Technical Reference

EA Boxer

Full web profile

Subaru EA82T

The turbocharged 1.8-liter SOHC boxer used in XT Turbo and Leone/GL Turbo applications.

Subaru EA82T engine

Subaru EA82T enginePhoto: Ken T1381 — CC BY-SA 3.0 — via Wikimedia Commons · source · license

★

Why it matters

Key takeaway

EA82T was Subaru's pre-EJ turbo boxer, foreshadowing the turbocharged AWD performance identity that later exploded with Legacy and Impreza WRX models.

Engineering

Technical specification

Architecture
Horizontally opposed boxer four
Block
Aluminum
Cylinder heads
Aluminum
Valvetrain
SOHC, 2 valves per cylinder
Aspiration
Turbocharged
Fuel delivery
Electronic fuel injection

The EA82T modernized Subaru’s older boxer platform with SOHC cylinder heads, electronic fuel injection, and turbocharging. It retained the 1.8-liter displacement but added the complexity and performance focus that foreshadowed the later EJ turbo era.

Factory fitment

Notable applications

Subaru XT TurboSubaru GL/Leone TurboSubaru RX Turbo

Strengths

  • Compact turbo boxer layout
  • Period AWD performance character
  • Important pre-EJ turbo history

Watch-outs

  • Cylinder-head cracking and heat management can be concerns
  • Timing-belt system is more complex than EA81
  • Limited modern aftermarket

Common upgrades

  • Intercooler retrofit
  • Exhaust
  • Modern engine management

Builder notes

Engineering notes worth knowing

01

1.781 L / 108.7 cu in boxer four with 3.622 x 2.638-inch bore and stroke.

02

Aluminum SOHC two-valve heads with electronic fuel injection.

03

Turbocharged in performance-oriented XT, GL/Leone, and RX applications.

04

Timing-belt-driven valvetrain made it more complex than the earlier pushrod EA81.

History & context

The story behind the engine

Before the WRX and EJ20 became synonymous with turbo Subarus, the EA82T was already pairing boost with Subaru’s boxer layout and AWD-oriented platforms. It was an important stepping stone toward the brand’s later performance identity.

Legacy

The EA82T is the bridge between Subaru’s simple early boxer engines and the sophisticated turbocharged EJ generation that made the brand famous with enthusiasts.

Verification

Reference sources

Subaru — Boxer engine history

manufacturer history

Subarus of the 80s — 1987 Subaru RX EA82T specifications

technical reference

TorqueList independent reference · Not an OEM publication or endorsement. Original TorqueList editorial and layout rights reserved.

End of public preview

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All-manufacturer workshop tools

Subaru Workshop Companion

Builder utilities and edition 2.0 reference sections. Calculations use your entered measurements; empty or unverified interchange, machining, power and torque data are never represented as confirmed specifications.

Public preview: workshop reference content remains limited until this volume is unlocked. The compression calculator is a general educational utility.

Engine geometry & static compression

Starting values are examples only, not specifications for any engine. Use measured dimensions. Dish and valve relief add clearance volume; dome subtracts it. Deck means piston below deck at top dead center. Calculations are for one cylinder except total displacement.

Geometry
Compression inputs

Static compression

9.63:1

Displacement

349.8 ci

Displacement

5.733 L

Mean piston speed

3,480 ft/min

Rod-to-stroke ratio

1.638

Clearance volume

83.02 cc / cyl

Static compression = (swept + clearance) ÷ clearance. Mean piston speed = 2 × stroke (feet) × RPM. These calculations do not predict fuel octane, dynamic compression, safe RPM, engine strength, horsepower, or whether a combination will clear mechanically.

Open permanent calculator link for print / QR codes

Attribution record

Image & License Credits

Only photographs recorded as approved for commercial use appear in this edition. TorqueList does not claim ownership of third-party photographs; all fallback technical artwork is TorqueList-created original material.

Subaru EA81 1.8

Ferjim

Public domain

Source: https://commons.wikimedia.org/wiki/File:Brat_(Custom).JPG

Subaru EA82T

Ken T1381 — CC BY-SA 3.0 — via Wikimedia Commons

CC BY-SA 3.0

Source: https://commons.wikimedia.org/wiki/File:Subaru_EA82_Turbo_in_Alcyone_XT.jpg

License: https://creativecommons.org/licenses/by-sa/3.0/

Layout adaptations of this photograph remain subject to the same indicated CC BY-SA license.

TorqueList is an independent automotive reference publication and is not affiliated with, sponsored by, endorsed by, or authorized by Subaru Corporation or any other vehicle or engine manufacturer.