The Porsche 991 is the internal designation for the seventh generation Porsche 911 which was unveiled at the 2011 Frankfurt Motor Show on 15 September as the replacement for the 997. The 991 is an entirely new platform, the fourth platform since the original 911 launched in 1963. The design has taken an evolutionary design step, in keeping with the previous generation 997 and 996.
Compared to the outgoing 997, the 991 is slightly larger, with the wheelbase increased by 100 mm (3.9 in) to 2,450 millimetres (96.5 in), and the overall length up by 70 mm (2.8 in) to 4,490 millimetres (176.8 in). A new transaxle was developed so that the rear wheels could be moved 76 millimetres (3 in) backward in relation to the position of the engine, which significantly improves the weight distribution and cornering performance of the new 911.
Due to the use of high-strength steels, aluminium and some composites the weight has been reduced to 1,380 kg (3,040 lb) for the manual Carrera, rising to 1,605 kg (3,538 lb) for the four wheel drive Turbo model with PDK.