The Porsche 911 GT3 is a high performance version of the Porsche 911 sports car primarily intended for racing. It is a line of high-performance models, which began with the 1973 911 Carrera RS. The GT3, introduced in 1999, is named after the Fédération Internationale de l'Automobile (FIA) Group GT3 class, in which it was designed to compete.
A number of variations, designed for road and track duty, have been introduced since its launch in 1999. More than 14,000 cars have been produced.
The GT3 has had a successful racing career in the one-make national and regional Porsche Carrera Cup and GT3 Cup Challenge series, as well as the international Porsche Supercup supporting the FIA Formula 1 World Championship. It has won championship and endurance races, including the GT class of the American Le Mans Series seven times, first overall in the 24 Hours of Daytona, and first overall at the 24 Hours Nürburgring six times.
The "GT3" nameplate was introduced in 1999 as part of the first generation of the Porsche 996 model range (commonly known as 996.1). As with Porsche's previous 911 RS models, the 996 GT3 was focused on racing, and so was devoid of items that added unnecessary weight to the car. Sound deadening was almost completely removed, as were the rear seats, rear loud speakers, sunroof, and air conditioning, although automatic air conditioning and CD/radio became no-cost optional add-ons.
The engine of the 996 GT3 set it apart from most of the other Porsche 996 models, although it shared the same basic design of the standard so-called "integrated dry sump" flat-six engine. The engine is naturally aspirated and based on the unit used in the Porsche 962 and Porsche 911 GT1 race cars. That engine was known as the 'Mezger' engine, after its designer Hans Mezger. The engine uses the original air-cooled 911's versatile dry-sump crankcase, with an external oil reservoir. The 996 GT3 has 360 PS (265 kW; 355 hp), compared to the 300 PS (221 kW; 296 hp) of the regular Porsche 996. In GT3 configuration, this so-called "split" crankcase (meaning the parting line of crankcase is on the crankshaft centreline) uses, instead of a fan and finned cylinders, separate water jackets added onto each side of the crankcase to cool banks of three cylinders with water pumped through a radiator. Thus, the GT3 engine is very similar to the completely water-cooled Porsche 962 racing car's engine, which is based on the same crankcase. The 962 differs, however, by using six individual cylinder heads while the GT1/GT3, like the air and water-cooled Porsche 959, uses two cylinder heads, each covering a bank of three cylinders. The GT3 engine could thus also be thought of as similar to a 959 engine, but with water-cooled cylinders. Up to early model year 2004 996 GT3 production, the basic casting used for the crankcase of the GT3 was the same as the air-cooled engine. The "964" casting number was visible on the bottom of the crankcase, and on areas normally machined in air-cooled applications, but not in water-cooled ones. The crankcase casting was changed in mid-2004 to a "996" casting number crankcase to eliminate these external air-cooled remnants, but internally it was the same.
Because the 911 air-cooled crankcase uses the Porsche 356 engine to transmission mounting flange configuration, the 996 GT3 used a manual gearbox also of air-cooled 911 heritage. This gearbox has interchangeable gear ratios and is more durable making it more suitable for racing than the standard 911 type 996 gearbox.
To bring the vehicle's track-prowess to the maximum level, Porsche endowed the GT3 with enlarged brakes, a lowered, re-tuned suspension system, lighter-weight wheels and a new front bumper with matched rear spoiler to help increase downforce, thereby increasing grip.
Porsche offered a no-cost option for the GT3 called the 'Clubsport' package. This option replaced the standard electrically adjustable leather front seats with manually adjustable racing buckets finished in fire-retardant fabric, single mass flywheel, bolt-in half-roll cage, 6-point drivers racing harness (also replacing the standard side airbags), fire extinguisher (mounted in the front passenger footwell) and preparation for a battery master switch. The Clubsport option was never offered to US customers, ostensibly due to the additional DOT crash testing that would have been required to allow US sales.
Porsche made significant updates to the GT3 for 2004 (the first year the car was offered to US customers), using the 2002 996 facelift including headlights that were differentiated from the Porsche Boxster. The 2004 version is commonly known as the 996.2 GT3. Horsepower was raised to 381 PS (280 kW) and torque to 284 lb⋅ft (385 N⋅m), 80% of which was available from 2,000 rpm. The braking setup was upgraded, now featuring 6-piston calipers on the front (rears remained 4-piston), and the Porsche Ceramic Composite Brake system was offered as an option.
In track testing by American automotive journals, the GT3 managed a 0-60 mph (97 km/h) time of 4.5 seconds and a quarter mile time of 12.0 seconds at 118 mph (190 km/h). During skidpad testing the vehicle posted 1.03g.
Porsche's official test-driver Walter Röhrl completed the Nürburgring Nordschleife with the 996 GT3 in 7 minutes 56 seconds, a feat which was used by Porsche to promote the car.
In 2003, Porsche introduced the Porsche 911 GT3 RS, an even more track-focused version of the 996 GT3. RS is short for the German RennSport, literally "racing sport" in English. The "RS" moniker, and the characteristic lightweight blue or red wheels and "GT3 RS" side stickers link the 996 GT3 RS to historically important Porsches such as the Carrera 2.7 RS of the early 1970s. The 996 GT3 RS is lighter than the 996 GT3 thanks to a polycarbonate rear window, carbon fiber hood and rear wing. Porsche Ceramic Composite Brake (PCCB) Carbon fibre-reinforced Silicon Carbide (C/SiC) ceramic composite brakes, which are also more heat and fade resistant than the cast iron units fitted as standard, are optional.
The 996 GT3 RS has a slightly different engine specification to the 996 GT3. The cylinder heads of the 996 GT3 RS have reshaped intake and exhaust ports for race homologation. Porsche claim the same 381 hp (284 kW) power output as the standard GT3 but Porsche's control dyno showed a jump to nearly 400 hp (298 kW) The RS also has progressive springs rather than linear. The dampers are uprated and are between 10 and 15 percent stiffer than the 996 GT3 in bounce and rebound.
The wheel carriers are totally redesigned to maximize the improved dynamic camber control. The suspension top mounts can be turned 120 degrees to a cup car position. Both front and rear control arms are adjustable. The RS is 3 mm (0.1 in) lower than the 996 GT3.
The RS rear wing delivers 35 kg (77 lb) of downforce at 125 mph (201 km/h). The RS has ram air ducts on the engine bay which force air into the intake with 18mb of pressure at 187 mph (301 km/h) and this is enough to create an additional 15 bhp (11 kW; 15 PS). That extra bhp cannot be homologated since the official engine output figures are certified on a dynamometer.
The Porsche 996 GT3 RS had a production run from 2003 to 2005. Only 140 right hand drive 996 GT3 RS cars were built by Porsche and 113 of those were officially imported into the UK. The 996 GT3 RS was not sold in the United States or Canada.
Automobile magazines claim the 996 GT3 RS can accelerate from 0-60 mph (97 km/h) in about 4.3 seconds, maintain over 1.0g on the skidpad, and have a top speed of around 190 mph (306 km/h).
In February 2006, Porsche revealed the second generation 997 GT3, commonly now known as the 997.1 GT3. In addition to a new 415 PS (305 kW) 3.6 litre flat-six engine, the vehicle featured "zero lift" aerodynamics, meaning the car creates only aerodynamic downforce and no grip-diminishing "lift" upwards and away from the road surface. The vehicle made use of a modified, track oriented version of Porsche's active PASM suspension making it the first of Porsche's RS or GT3 versions to feature an electronically adjustable suspension system. Also available was a navigation system and Porsche's "sports chrono" gauge package. The car went to sale in summer of 2006 and had a starting price of US$106,000. A total of 917 units were sold in the United States and 46 units in Canada.
The vehicle has a rated 0-60 mph (97 km/h) time of 4.1 seconds and has a top speed of 193 mph (311 km/h). Road and Track was able to achieve a 0-60 mph run in 3.8 seconds. Porsche's official test-driver Walter Röhrl completed the Nürburgring Nordschleife in 7 minutes 42 seconds with the 997 GT3 in 2006.
Porsche also offered an RS version of the 997 GT3. In common with its predecessors, it provided a homologation model for use in a range of racing series. The 997 GT3 RS was released in Europe in October 2006 and in North America in spring 2007.
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