The SUBARU BOXER Engine

For the first time in 21 years, every function in this new boxer engine has been renewed to meet the demands of a new era. Thanks to across-the-board improvements including longer stroke, more compact combustion chambers, improved intake and exhaust efficiency due to the installation of dual AVCS, lighter piston weight, and decreased engine wear, the next-generation boxer realizes high combustion efficiency and superior fuel economy.

It has also successfully realized refreshingly responsive acceleration as well through rich reserves of low- to mid-range torque. All of these improvements deliver even greater everyday usability. By achieving both a high degree of environmental performance and driving pleasure, this boxer is worthy of being called a next generation engine.

This highly efficient turbocharged engine offers well balanced specifications for the entire car, including in terms of power, fuel efficiency, fuel type, and displacement. Equipped with direct fuel injection and Auto Stop Start System, this engine delivers high power without the feel associated with a small-displacement engine and great fuel efficiency without the feel associated with a turbocharged engine. SUBARU’s next-generation turbo engine is also cost-efficient since it uses regular gasoline, and the engine has good touring performance.

The FA20 builds on the base of the next-generation boxer engine’s design concept to develop a new normally aspirated engine, which aims for higher output and environmental performance as well as an even lower center of gravity. In addition to squaring the bore and stroke, the FA20 also incorporates the next-generation “D-4S”* direct injection technology. It has also realized output performance of 100 PS per liter, as well as low fuel consumption and cleaner emissions.

This engine, with the attention paid to aspects such as the engine note transmitted to the vehicle cabin, allows you to experience the enjoyment of the boxer engine to the fullest.
* D-4S：Direct injection 4 stroke gasoline engine Superior version

The FA20 DIT is based on the next-generation boxer “FA20”, and in a first for SUBARU, introduces Direct Injection turbo technology. Thanks to improvements to the knock resistance threshold, due to the adoption of direct injection as well as precise fuel injection control, the FA20 DIT has realized a high compression ratio and high efficiency that would have been impossible for previous turbo engines.

Despite being a 2.0-liter engine, the FA20 DIT boasts dominant sports performance, which surpasses large-capacity turbo engines, and unbelievably low fuel consumption and low exhaust emissions from that power. It is fair to say that the FA20 DIT offers the performance of a truly next-generation sports machine.

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.

Designed in pursuit of a light and compact design. By adopting direct control, quick response to gear shifts and a smooth feel have been achieved. Downshift blipping control featured in the SUBARU BRZ enables smooth gear shifting by synchronizing the engine speed when moving into lower gears and increases the enjoyment of driving a sports car.

The vertical transmission available only with symmetrical AWD achieves a superior feeling of moderation and rigidity. The gear ratio is set at the level that maximizes fuel efficiency and driving performance. Subaru raises the level of enjoyment of driving and controlling a vehicle by individually developing the MT for each car model.