What size engine is in the Subaru Boxer?
Subaru’s Boxer engines (horizontally opposed four-cylinders) come in several displacements. There isn’t a single “boxer size,” but the most common modern sizes are 2.0, 2.4, and 2.5 liters, with turbo variants at 2.0 and 2.4 liters. This article outlines those sizes, how they’ve been used across models, and what it means for performance and reliability.
Boxer engine sizes used by Subaru
Overview of typical displacement sizes used in Subaru’s boxer engines, including both current and historical examples.
- 2.0 L (approximately 1998 cc): A staple in several turbocharged and early FA/ EJ-era engines. In modern performance models, the 2.0 L displacement has been prominently used in turbocharged variants such as the WRX.
- 2.4 L (approximately 2387 cc): Appears in both turbocharged and naturally aspirated forms in newer Subarus. The 2.4 L turbo is used in recent WRX variants, while the 2.4 L naturally aspirated version powers models like the BRZ in some markets.
- 2.5 L (approximately 2498 cc): A common naturally aspirated size for mainstream models, including Outback, Legacy, Forester, and some Impreza configurations.
In short, Subaru’s boxer family currently centers on 2.0, 2.4, and 2.5-liter displacements, with turbocharged versions amplifying output in the 2.0 and 2.4 L ranges. The exact size you find depends on the model and year.
Current lineup examples (displacement focus)
Illustrative examples of where these sizes show up in the contemporary lineup. This helps map size to common models without listing every version.
- 2.0 L (turbocharged): Performance-focused models such as the WRX rely on a 2.0-liter turbo engine for strong torque and brisk acceleration.
- 2.4 L (turbo/NA): The 2.4-liter displacement appears in both turbocharged forms (as in the latest WRX) and naturally aspirated forms (as in some BRZ variants in certain markets).
- 2.5 L (NA): The workhorse size for many daily-driver Subarus, used widely in models like Outback, Legacy, Forester, and related trims where smooth, reliable power is desirable without forced induction.
These examples illustrate how the sizes map to different models, underscoring Subaru’s use of multiple displacements to balance efficiency and performance across the lineup.
Historical context
The Boxer layout has been a Subaru hallmark for decades. Earlier EJ-series engines offered 2.0L and 2.5L displacements, and as Subaru moved to the modern FA/FB engine families, the 2.0L, 2.4L, and 2.5L sizes continued to evolve to meet emissions, efficiency, and performance targets. Today’s lineup keeps the flat-four concept while varying displacement to suit different driving needs and markets.
In summary, the size of a Subaru Boxer engine isn’t fixed to a single figure. The lineup commonly uses 2.0, 2.4, and 2.5-liter displacements, with turbocharged variants at 2.0 and 2.4 liters providing higher performance. The exact engine size for a given Subaru depends on the model year and grade you’re considering.
What this means for buyers
When shopping, check the exact engine displacement and code for the specific model year. If you want stronger performance, look for turbocharged 2.0 L or 2.4 L variants; for everyday reliability and efficiency, a 2.5 L naturally aspirated engine is a solid choice.
Summary: Subaru’s Boxer engines span 2.0, 2.4, and 2.5 liters, with turbo variants in the 2.0 and 2.4-liter range. The precise size varies by model and year, reflecting a balance between performance needs and everyday practicality.
Is the Subaru 2.4 boxer engine reliable?
Subaru's 2.4-liter turbocharged engine has been known to last over 150,000 miles with routine maintenance. All of the issues mentioned here can be avoided entirely with proper care. This makes this engine hard to beat.
What is special about the Subaru boxer engine?
Benefits of the SUBARU BOXER Engine
Reduced vibration: Since it operates symmetrically and entirely on one horizontal plane, the SUBARU BOXER engine tends to cause less vibration, resulting in a smoother, more comfortable drive.
How much horsepower does a 2.0 boxer have?
2.0-liter and 2.5-liter Flat-4
Producing 148 and 170 horsepower respectively, these 4-cylinder engines combine capable power, impressive efficiency, and impeccably smooth operation.
How much horsepower does a 2.5 boxer engine have?
A naturally aspirated 2.5L Subaru Boxer engine produces 182 horsepower and 176 to 178 lb-ft of torque. However, a turbocharged version of the 2.5L engine, found in the WRX STI, is much more powerful, generating 310 horsepower.
This video explains the difference between the 2.5L and 2.0L Subaru Boxer engines: 1mTDTVGarageYouTube · Apr 18, 2023
Naturally aspirated (non-turbo)
- Horsepower: 182 hp
- Torque: 176–178 lb-ft
- Note: This is the standard engine in models like the Subaru Forester, Outback, and higher trims of the Crosstrek.
Turbocharged
- Horsepower: 310 hp
- Torque: 290 lb-ft
- Note: This engine is found in the WRX STI.
This video compares the 2.5L and 2.4L Turbo Boxer engines in the Subaru Outback: 1mAlex PrestigiacomoYouTube · Aug 31, 2022
