Subaru firmly believes that the Horizontally-Opposed Engine is the optimum design for driving enjoyment. The pistons face away from each other in a 180º symmetrical layout around the crankshaft and work to balance out each other’s vibrations, delivering a smooth, shudder-free feel. This is because the engine can rotate freely at any given speed, delivering heart-gripping response to the driver. The length and height of this engine layout can be kept shorter than a traditional in-line engine, and it is also lighter. The engine can be mounted lower in the vehicle than other engines, and weight balance on the left and right can be made almost exactly the same. In this design, the low centre of gravity engine lowers the centre of gravity of the entire car. Similarly, a symmetrically balanced engine increases the symmetrical balance of the entire car. Both of these aspects combine to deliver a safer, more stable, and ultimately, more enjoyable experience on the road.


The new generation BOXER engine, FA20, now comes mounted with Subaru’s first direct injection turbo. This helps raise the anti-knock limit and provides more precise fuel injection control, resulting in a higher compression ratio and greater efficiency that could not be attained with previous turbo engines. The 2.0-litre delivers power rivalling that of much larger capacity turbo engines for truly exceptional sports performance, yet comes with unbelievably low fuel consumption and exhaust gas emissions. True onroad performance befitting of a sporty, next-generation power unit.
With the new-generation BOXER engine used as the basis for design, engineers focused on developing a new NA engine with the aim of delivering high power output and environmentally-friendly performance, combined with the benefits of a low centre of gravity. A square bore and stroke layout has been combined with D-4S next-generation direct injection technology to deliver an impressive 100PS per litre power output, all with lower fuel consumption and exhaust gas emissions. The classic BOXER sound can still be felt in all its glory from within the cockpit, in a design that has been engineered to maximise the fun that the BOXER delivers.

To meet the constantly changing needs, a completely new BOXER engine was engineered from the ground up, with new enhancements across the board being implemented. A longer stroke and more compact combustion chamber combine with a dual AVCS for better intake and exhaust efficiency, lighter pistons and reduced friction throughout the engine, bringing exceptional efficiency and impressive performance. Mountains of low-speed torque mean exciting acceleration response, making the engine easier to handle in day-to-day driving. It’s an engine designed for both environmental responsibility and fun, in what can only be called a new-generation powerhouse.

The world's first commercial Horizontally-Opposed Diesel Engine developed for passenger vehicles is the SUBARU BOXER DIESEL. When petrol engines are converted to diesel, strengthening of the engine block usually makes the engine bigger and heavier. The SUBARU BOXER, however, was originally designed with rigidity in mind, allowing the 92.0 mm x 75.0 mm bore and stroke of the 2.0-litre petrol four-cylinder engine to be changed to a square 86.0 mm x 86.0 mm design. The result is a more compact combustion chamber and greater fuel efficiency, and combined with a higher pressure common rail fuel injection, an improved oxidizing catalyst with closed Diesel Particulate Filter (DPF), a variable nozzle turbo and electric power steering, these all help to reduce fuel consumption and CO2 emissions. Ceramic glow plugs also quicken starting in cold weather. And whilst meeting the ultra-clean EURO5 emission standards, the engine delivers even more torque compared to previous models. A prodigious 350-Nm of peak torque is delivered at a lower 1,600 rpm – providing smooth, free-breathing performance at any speed. These advantages are evidence of the vision that Subaru has in using the Horizontally-Opposed Engine.