The Porsche 911 GT3 RS (991.2) has a 4.0-litre engine.
The 991.2 designation refers to the facelifted version of the 991-generation 911. Porsche unveiled the updated GT3 RS in February 2018, fitting it with a naturally aspirated boxer flat-six related to the engines used in the GT3 and racing-derived 911 RSR. The engine retained a 4.0-litre displacement and gained a 9,000-rpm redline.
Compared with the earlier 991.1 GT3 RS, the facelift brought more power and torque, revised aerodynamics and additional track-focused details. Changes included NACA brake-cooling ducts, a modified front fascia, a larger-style rear wing, ball joints on the suspension links and lighter glazing. A Weissach package added further carbon-fibre components and optional magnesium wheels.
The 4.0-litre figure is easy to confuse with other 911 engines. The earlier 991.1 GT3 RS also used 4.0 litres, while the regular 991 GT3 began with a 3.8-litre engine before the 991.2 GT3 moved to 4.0 litres. The displacement therefore identifies the engine size, not the exact facelift alone.