Meet Subaru’s New FA24 Boxer Engine

The FA24 is the most modern engine in Subaru’s lineup. Get acquainted.

byJames Gilboy|
Subaru News photo

Subaru announced an all-new engine would power its most tow-friendly SUV, the Ascent, Thursday. There wasn't space to geek out on the new engine—confirmed to The Drive by Subaru to be designated FA24—in my article on the Ascent, so for the sake of Subaru enthusiasts, tired of the company's aging engine architecture, the FA24 is getting the spotlight to itself today.

The FA24 has all-aluminum heads and block, to keep weight down and warm-up rapid. In its heads spin dual overhead cams, driven by a timing chain rather than a belt, actuating 16 valves with variable timing.

Its cylinders displace a total of 2,387cc, rounded to 2.4-liters, with a 94-millimeter bore and an 86-millimeter stroke. The compression ratio sits at a tall 10.6:1, keeping cylinder pressures high for efficiency. Direct injection overcomes high cylinder pressures to deliver fuel to the cylinder before combustion sends exhaust gases through the low-lag twin-scroll turbocharger, which sends boost through an intercooler and back into the engine.

This action is good for 260-horsepower at 5,600 rpm, and a broad peak torque band of 277 pound-feet between 2,000 and 4,800 rpm.

The humble state of tune for an internal combustion with all this modern tech intrigued us here at The Drive; there has got to be more in this puppy. Ford's smaller 2.3 Ecoboost has greater torque and horsepower, albeit with a lower compression ratio. We reached out to Subaru for more information on the FA24, including information on its state of tune in the Ascent, and the possibility of the engine making its way into future Subarus.

"The engine was designed for torque, not horsepower," a Subaru spokesperson told The Drive, regarding the FA24's power output in the CVT-equipped Ascent. "It is as quick or quicker than the competition and quite good under full load."

Information on the FA24's peak boost pressure was not divulged, but the spokesperson said there would be "more information available at the launch."

Whether the FA24 (or derivatives) will be seen in other vehicles manufactured by Subaru, such as the Forester, WRX, or BRZ was asked, but the spokesperson declined to comment, stating company policy against discussing future products and applications.