What is the most powerful Subaru motor?
In today’s production road cars, Subaru’s most powerful engine is the 2.4-liter turbocharged FA24F, used in the WRX, delivering about 271 horsepower (roughly 258 lb-ft of torque). If you count historic and race-focused engines, Subaru has produced higher-output units such as the 2.0-liter turbo EJ207 used in Japan’s STI Spec C lineage, which produced around 320 PS, making it the peak output in Subaru’s factory lineup when homologation variants are included.
Defining power and scope
To answer the question clearly, this article distinguishes between: (a) current street-legal production engines, (b) production engines used in limited-run or homologation cars, and (c) race-spec or concept engines. horsepower ratings can differ by market and model year, and “most powerful” can mean peak horsepower, torque, or overall performance envelope.
Current production powerplants
Subaru’s present road-going lineup centers on the FA24 family, with tuning that yields the highest output in the WRX. The following notes reference the production engines that currently sit at the top end of Subaru’s street-car power output.
- 2.4-liter turbocharged FA24F: approximately 271 horsepower and around 258 lb-ft of torque in the WRX; also used in detuned or differently tuned forms in other models such as Outback and Legacy.
- Remark: The same FA24 family powers the BRZ/GR86 in a naturally aspirated configuration (roughly 228 hp in U.S. spec), illustrating how the engine family spans a range of outputs depending on tuning and model.
In road cars, the 2.4-liter turbo family currently offers Subaru’s peak horsepower in a factory, street-legal context. Exact numbers vary by model year and market, with 271 hp serving as the benchmark for the WRX in recent years.
Historically powerful Subaru motors
Looking back, Subaru produced engines with higher peak horsepower in performance and rally-spec machines, especially within Japan’s STI lineup and late EJ-series turbo engines. The following examples are notable for their high output in factory or homologation contexts.
Before listing, it’s helpful to note that Subaru’s most extreme outputs have often come from Special/Spec C and homologation variants designed for racing or rally compliance.
The following highlights cover standout powerplants from Subaru’s history.
- EJ207 2.0-liter turbo (Impreza WRX STI Spec C and related Japan-only variants): roughly 320 PS (about 315–320 hp) in Japanese-market STI configurations; widely cited as one of Subaru’s most powerful factory engines in production-like form.
- EJ25 turbo (various STI variants in the late 2000s and early 2010s): around 300–310 hp in U.S.-market STI models, with higher outputs in some Japanese-homologation versions.
- EJ257 (2.5-liter turbo, US STI lineage): commonly rated around 300 hp in early years and up to about 305–310 hp in later iterations; a benchmark figure for US-market performance during that era.
These engines illustrate that Subaru’s most powerful powerplants in its history come from turbocharged EJ-series engines, particularly in Japanese-spec STI variants and late-era turbocharged configurations.
What counts as "most powerful"? caveats and context
The phrase "most powerful" can mean different things: raw horsepower, peak torque, or power-to-weight performance. It also depends on whether you count modern road cars, all production/homologation engines, or race-only machines. Subaru’s current streetcar horsepower leader sits with the FA24F 2.4L turbo, while the absolute peak in factory performance historically belongs to certain EJ207/JDM STI variants. For enthusiasts, this distinction matters when discussing performance potential versus reliability and availability.
Summary
Today, the strongest production Subaru engine in a road-legal car is the 2.4-liter FA24F turbo, delivering about 271 hp in the WRX. Historically, Subaru’s most powerful factory motors were turbocharged EJ-series units, notably the EJ207 in Japanese STI Spec C variants (around 320 PS) and EJ25 turbo iterations in late-2000s US STI models (roughly 300–310 hp). The definition of “most powerful” depends on whether you count modern street cars, all production/homologation engines, or race-only machines.
