Porsche 996 - GT Variants

GT Variants

The 996 platform was used as the basis for two lightweight GT variants called GT2 and GT3. The GT3 was based on the standard 996 Carrera, but was stripped of a great deal of equipment for weight savings, featured stiffer, adjustable suspension and upgraded brakes, and used the bodyshell of the four-wheel-drive version, which incorporated additional front-end stiffening. It was produced in two versions. The first, commonly referred to as the Mk.I GT3, was released in 1999 in all markets, save North America. It featured a naturally aspirated version 3.6L flat six making 360 bhp (270 kW). This engine was shared with the 996 Turbo and was a derivative of the Le Mans winning engine developed for the 911 GT1. The Mk.II GT3 variant was based on the second generation of the 996, and featured updated aerodynamics, and a more powerful version of the 3.6L engine from the MK.I, now producing 380 bhp (280 kW). The Mk.II was the first GT3 marketed in the North America. In a 2004 testing of the Mk.II GT3, the car accelerated 0-60 mph in 4.0 seconds, and produced 1.03 g on the skidpad, the second highest number ever recorded by a street legal automobile.

Also its counterpart, the GT2, was RWD to save weight and to avoid power losses through the transmission. (This is primarily due to the fact that it was built to compete in GT2 class racing, which mandated RWD). It received an added group of aerodynamic body parts, and a re-tuned version of the 996 Turbo's 3.6 litre, twin turbocharged engine featuring larger turbochargers and intercoolers, revised intake and exhaust systems, and re-programmed engine control software. The result was 489 hp (365 kW) and 484 lb·ft (656 N·m) of torque respectively, enough to launch the car from 0 to 60 mph (97 km/h) in 3.9 seconds and to a top speed of 198 mph (319 km/h). Bigger wheels and tires along with lightweight ceramic brakes were standard. The GT2's fixed rear wing (made of CFRP for the post-2003 cars) appears to be a concession to racing rules that usually outlaw moving aerodynamic devices. It had no rear seat and no air conditioning. Both cars were available only with six-speed manual transmissions.

The Turbo, GT2 and GT3 models use the Aluminum crankcase of the air-cooled 911 with its true dry sump oiling system. The six separate individual Nikasil lined cylinders in this engine are covered with two separately installed water jackets each covering a bank of 3 cylinders on each side of the engine, thus adding water cooling to a crankcase originally designed for air-cooled cylinders (the normal 996 Carrera engine has the cylinders and water jackets cast together with the crankcase). This engine is very similar to that of the Le Mans winning Dauer Porsche 962 and Porsche GT1 racing cars' engines.