Subaru Boxer engines are mounted longitudinally in the chassis, resulting in better balance, reduced driveline friction and efficient power distribution. For added safety, the Subaru Boxer engine’s placement minimizes the chance of harmful intrusion into the cabin during a frontal collision.

According to their engineers, these high-powered engines are ideal for all-wheel-drive applications used in Subaru vehicles because they are inherently compact — short and low. The layout concentrates its mass in a small area and contributes to a lower center of gravity.

The 6-cylinder engine (H6-3.0L) used in such models as the Outback is compact in design and only slightly longer than the 2.5L 4-cylinder engine that powers other Subaru models (see illustration).

Mounting the boxer engine longitudinally (front to back) allows the transmission to be mounted directly behind it.
Since power travels in a straight, near-horizontal line to the rear differential, it helps minimize frictional loss. This symmetrical, uniform layout also provides excellent left-right balance. By comparison, in a vehicle with a transverse (sideways) mounted engine, an all-wheel-drive system requires additional components to reroute the power from a sideways orientation to front-to-bac...