Subaru's new FB engine architecture has so far only made it to the US under the hood of the new Forester, and only in naturally-aspirated form. That is set to change in 2012, when Subaru will release turbocharge variants displacing either 1.6- or 2.0-liters. These new FB turbo engines will replace the current EJ turbos, and while they are still flat-4's, they are slightly different. The turbocharges have been moved under the engine, from the EJ's high mounting position.

The intercooler, in true Subaru fashion, remains mounted directly over the engine. The 2.0-liter FB is said to produce 300 horsepower and find a home under the hood of the STi. This is the same amount of power produced by the current engine, but the new one will get 10 percent better fuel economy.