What engine is in a 2015 Subaru Legacy?
The 2015 Subaru Legacy offers two engine options: a 2.5-liter flat-four and a 3.6-liter flat-six. Most buyers end up with the 2.5-liter, while the larger engine is available on higher trim levels for extra power.
This article explains the two engine choices for the 2015 Legacy, including their outputs, transmissions, and how they affect performance and fuel economy.
Engine options for the 2015 Legacy
Below are the two engine options offered for this model year, along with key details about output and drivetrain.
2.5-liter FB25 flat-4
Configuration: horizontally opposed four-cylinder. Output: approximately 173–176 horsepower and about 174 lb-ft of torque. Transmission: typically paired with Subaru's continuously variable transmission (CVT). Drivetrain: all-wheel drive is standard on Legacy models outside of some market-specific configurations. This engine is the standard offering on most trims, prioritizing efficiency.
3.6-liter EZ36 flat-6
Configuration: horizontally opposed six-cylinder. Output: about 256 horsepower and 247 lb-ft of torque. Transmission: paired with a five-speed automatic transmission (no manual option for this engine). Availability: offered on higher-end trims of the Legacy (such as 3.6R/Limited configurations) for stronger performance. Fuel economy is lower than the 2.5L option due to the larger displacement.
In short, the 2.5L version emphasizes efficiency and everyday usability, while the 3.6L version provides a noticeable boost in acceleration and power at the expense of fuel economy.
Performance and efficiency notes
Both engines drive all-wheel drive as part of the Legacy platform, but their outcomes differ. The 2.5-liter engine typically delivers better fuel economy and sufficient power for most driving needs, making it the common choice for daily commuting. The 3.6-liter flat-six offers stronger performance, smoother and more confident acceleration, and is aimed at buyers who value power and refinement over maximum efficiency.
Fuel economy and real-world performance vary with driving conditions, transmission choice, and optional features. The 2.5L's CVT tends to optimize efficiency, while the 3.6L's automatic gearbox prioritizes performance characteristics.
Summary
The 2015 Subaru Legacy provides two engine options: a 2.5-liter FB25 flat-4 and a 3.6-liter EZ36 flat-6. The 2.5L is the standard, efficiency-focused choice, typically paired with a CVT and standard AWD. The 3.6L is available on higher trims, delivering stronger horsepower and torque via a 5-speed automatic. Prospective buyers should weigh the desire for fuel economy against the need for power and acceleration when choosing between them.
