Kalliokoski Motorsport will be competing in a Mercedes Rallycross SuperCar powered by a turbocharged 2.0 L Rex inline-four built by Elmer Racing in Kirkkonummi, Finland. You might remember Elmer Racing builds a turbocharged 4.0 L inline-four called Thor. Well Rex is a similar full billet design featuring a 2.0-2.4 liter displacement. The motor that is in Kalliokoski’s Rallycross is a IA 45 mm inlet restricted turbocharged 2.0 L inline-four. Elmer Racing states a non-restricted turbocharged 2.4 L Rex inline-four is capable of over 1,000 horsepower on moderate boost.
Source: Elmer Racing FB page