Here year is year of introduction, not model year
* with Launch Control
Before the production of the 991 GT3 started, 14.145 GT3 cars of 996 and 997 generations were made between 1999-2012.
2013 March 5. Geneva Motor Show, 991 GT3 & GT3 Cup launch. Persons featured in the video include Andreas Preuninger, Jacky Ickx and Michael Mauer (Director Porsche Style).
The many questions
The 991 GT3 came with more questions than answers. Why isn't the "lightweight 911" light? Why isn't the manual gearbox available? Why does it have 20" wheels, when it is proven that 18" is optimal for racing use...
Engine
The new 3.8-litre GT3 engine was a technological marvel. As there are rules and therefore restrictions for the racing cars, the street-legal 991 GT3 had more power than the 991 GT3 Cup car. Both had 3.8-litre engines, but the racing variant had 338 kW compared to the street version's 350 kW. The street engine had a rev limiter set 500 revolutions higher, at 9000 rpm instead of 8500 rpm in the Cup car. Although not as powerful, the racing version was naturally much-much lighter.
Engine problem on early cars
Porsche press release from March 19, 2014, said the engines of the first 785 produced 991 GT3 will be replaced by the Porsche Centres. They found the engine could be damaged by the loosened screw joint on the connecting rod, leading to engine destruction and oil getting on hot exhaust which could start a fire.
Gearbox
Even though the GT3 version of the PDK gearbox was 2 kg / 4 lb lighter than the PDK in the Carrera, the car suffered 18 kg / 40 lb weight increase due to the automatic transmission. The PDK came with a "paddle-neutral" feature - if the driver pulled both shift paddles simultaneously, both clutches were opened and the flow of power from engine to real wheels was cut off.
Rear axle steering
The 991 GT3 was 70 kg/154 lb heavier than the preceding 997 GT3 RS 4.0 and to cope with the weight, rear axle steering was used. At speeds of up to 31 mph/50 kmh, the system steers the rear wheels into the opposite direction of the front wheels, between 31-50 mph/50-80 km/h, the rear wheels are not steered and at speeds above 50 mph/80 km/h, the system steers the rear wheels parallel to the front wheels, so the car can easily change lane going sideways.
Tyres
The 991 GT3 was equipped with Dunlop Sport Maxx Race tyres, a new alternative to the Michelin Pilot Sport Cup tyres. The sizes were 245/35 ZR20 (91Y) N0 and 305/30 ZR20 (103Y) XL N0. "N zero" says a tyre is created specifically for Porsche.
