It is a derivative of the FB engine, with efforts to reduce weight while maintaining durability as the main design goals.

[2] A direct injection-only turbo variant of the FA20, the FA20F, was introduced in late 2012 with the 2012 Legacy GT (for the Japanese market) and in the United States, the 2014 model year Subaru Forester.

[12] The engine has an all aluminum head and block in order to keep weight and warm-up times low.

[12] Direct injection and a turbocharger are used to provide output comparable to a 6-cylinder naturally aspirated engine, and the FA24 uses "regular" (87 AKI) fuel.

It has the same displacement as the FA24F turbocharged engine with an identical 94×86 mm bore and stroke, but the compression level is increased to 12.5:1.

[18][19] Fitting the existing FA24F, with its bottom-mounted turbo, to the second generation Subaru BRZ/Toyota 86 would have required raising the price and overall center of gravity, so natural aspiration was chosen instead.