The 2013 Subaru Legacy uses a 2.5-liter flat-four boxer engine as standard, with an optional 3.6-liter flat-six available on higher trims.
Engine options in 2013 Legacy
Here is a concise look at the two powertrains that could equip the 2013 Legacy. The boxer layout is a hallmark of Subaru, contributing to a low center of gravity and balanced handling.
- 2.5-liter flat-four (boxer) engine — Naturally aspirated, producing about 170 horsepower and around 170 lb-ft of torque. This engine powers most Legacy trims (the standard setup).
- 3.6-liter flat-six engine — Approximately 256 horsepower and 247 lb-ft of torque. This is the optional upgrade found on higher trims such as the 3.6R.
Note that horsepower and torque figures can vary slightly by market and transmission choice, but these are the typical outputs seen in the U.S. lineup for 2013.
Why the boxer design matters
Boxer engine fundamentals
Subaru’s Legacy uses a horizontally opposed “boxer” layout, where opposing pistons move in and out together. This design lowers the engine’s center of gravity, reduces vibration, and pairs with Subaru’s symmetrical all-wheel-drive system to enhance stability and handling in varied conditions.
Practical implications for drivers
For everyday driving, the 2.5-liter engine emphasizes efficiency and smoothness, while the 3.6-liter option delivers stronger acceleration and highway performance—appealing to buyers seeking extra power without sacrificing the all-wheel-drive character Subaru customers expect.
Summary: The 2013 Subaru Legacy offered two engines—the standard 2.5-liter flat-four boxer and an available 3.6-liter flat-six—delivering roughly 170 hp/170 lb-ft and 256 hp/247 lb-ft, respectively. Both engines use Subaru’s boxer design to complement the vehicle’s all-wheel-drive setup and handling goals.