Jun 12, 2011

Porsche 911 GT2 (2002)

The 2002 Porsche 911 GT2 takes its place at the top of the current Porsche model range as the most powerful and fastest member of the 911 family. The turbocharged Porsche 911 GT2 is 10-percent more powerful and seven-percent lighter than the 911 Turbo on which it is based, and its chassis modifications come directly from Porsche's road racing experience.
"The GT2 is the best example yet of how Porsche applies its racing experience and success to production cars," said Frederick J. Schwab, president and CEO, Porsche Cars North America.
Racetrack Record Setter
The biggest weight savings over the 911 Turbo comes from making the GT2 rear-wheel drive (the 911 Turbo is all-wheel drive). Porsche tests all its models at the world-famous Nurburgring racetrack in Germany, where the Porsche 911 GT2 shattered all lap time records for street-legal production cars -- including a few set by other Porsches.
456-Horsepower Twin-Turbo Engine
The Porsche 911 GT2 engine, a modified version of the 3.6-liter twin-turbo six-cylinder "boxer" engine from the 911 Turbo, produces 456 horsepower (SAE) at 5,700 rpm compared to 415 horsepower at 6,000 rpm in the 911 Turbo. The power increase and approximately 220-pound total weight reduction give the Porsche 911 GT2 a power-to-weight ratio of 6.9 lb. per horsepower (4.23 kg per kW), resulting in even more astounding performance than the 911 Turbo. The 911 GT2 is capable of accelerating from zero-to-62 mph (zero-to-100 km/h) in about four seconds and can achieve a top track speed of 195 mph (315 km/h).

 
Functional Design
Design changes that set the Porsche 911 GT2 apart from the 911 Turbo also add function, including larger front air intakes and an additional air intake ahead of the front hood. In back, redesigned air intake scoops moved far to the outside reveal the greater need for cooling air. The Porsche 911 GT2 replaces the two-piece automatic-deploying spoiler of the 911 Turbo with a new, one-piece fixed-design wing. As on the 911 Turbo, Bi-Xenon headlights are standard.
More Downforce
Because the Porsche 911 GT2 is capable of extremely high racetrack speeds, Porsche refined the aerodynamic characteristics to produce greater downforce, even sacrificing a lower coefficient of drag (Cd) to do so. Suspension modifications lower the car by 0.78-inches front and rear, reducing both wind resistance over the car and the airflow beneath the car that can cause lift. The changes reduce undercar airflow by 60 percent compared to the 911 Turbo.
Ducting hot air away from the front central radiator through a vent in the hood also reduces lift forces. The front edge design of this vent causes air flowing above the car to generate and additional suction effect, which in turn increases velocity of air flowing through the central radiator.
The lower section of the front apron, too, has been designed to generate additional downforce on the front of the car while reducing airflow underneath it. The three large polypropylene panels used on all 911 models merge into a special panel under the GT2 that directs cooling air to the transmission.
Compared with the rear wing of the 911 Turbo, the wing on the Porsche 911 GT2 is higher and extends further to the back to produce even greater downforce at higher speeds. Ducts in the ends of the wing feed fresh air to the engine. Air enters a collector box inside the wing and then goes straight into the air filter. The wing angle can be adjusted from 1-6 degrees for racetrack driving.
Staggering Power and Performance
While the Porsche 911 GT2 shares its basic powerplant with the 911 Turbo, the dual turbochargers provide an even greater throughput of air, allowing an increase in turbo boost pressure under full load to 14.5 psi (1.0 bar over atmosphere), compared to 11.76 psi (0.8 bar) for the 911 Turbo. Larger-capacity intercoolers keep the air charge temperature consistent despite the increased boost pressure.
At the GT2 engine's power peak speed of 5,700 rpm, boost pressure reaches 13.8 psi (0.95 bar) and then peaks at 14.5 psi (1.0 bar) over 6,200 rpm. As a result, the Porsche 911 GT2 maintains an almost consistent power level even above the engine's power peak speed, despite the increase in exhaust backpressure at such high speeds. Maximum engine speed is 6,750 rpm, same as the 911 Turbo.
The GT2 engine produces maximum torque of 457 lb.-ft. (620 Nm) from 3,500-4,500 rpm for response normally associated with engines of far larger displacement. In comparison, the 911 Turbo produces 415 lb.-ft. of peak torque from 2,700-4,600 rpm.
VarioCam Plus
As on the 911 Turbo, the Porsche 911 GT2 engine employs the VarioCam Plus variable valve lift and timing system. Axial camshaft adjustment provides variable intake valve timing, while variable lift is achieved using two switching cup tappets on the intake side operated by two different size lobes on the intake camshaft. VarioCam Plus serves, first, to optimize engine output and torque and, second, to improve fuel economy and exhaust emissions as well as the engine's smoothness and refinement.
Dry Sump Oil System
Typical of racecar practice a so-called dry sump lubrication system with a separate oil tank fitted directly to the engine ensures a reliable supply of oil. Optimized design and configuration of the oil pumps in conjunction with the right capacity of the oil tank ensures that the engine receives a reliable oil supply even under extreme acceleration, braking and cornering. The oil volume within the entire system is approximately 11.6 quarts (11 liters).
Except for mufflers with less backpressure, the exhaust system is essentially the same as in the 911 Turbo. Like the 911 Turbo, the Porsche 911 GT2 complies with the U.S. Low Emissions Vehicle (LEV) standard.
Manual Transmission Only
Power is transmitted to the rear wheels of the Porsche 911 GT2 by a six-speed manual gearbox. An evolutionary version of the transmission from the 911 Turbo, this unit uses external transmission oil cooling and injection oil lubrication. The Tiptronic S five-speed automatic transmission is not available for the GT2.
The ratios of the individual gears as well as the final drive are the same as on the 911 Turbo, as are the various design features ensuring greater stiffness and enhanced noise control. The synchronizer rings on the gears are made of steel instead of brass to provide even greater durability.
The GT2 uses a special asymmetric limited-slip differential, which provides up to 40-percent locking under power. On overrun, the differential provides up to 60-percent locking, which helps stabilize the car in curves under load changes.
Modified Suspension
The suspension of the Porsche 911 GT2 is designed to cater to an even higher level of performance than the suspension of the 911 Turbo. Modifications include fitting racing springs that lower the center of gravity by 0.78-inch (20 mm), adjustable anti-roll bars and an even wider range of suspension geometry adjustment to accommodate racing tires.
The GT2 uses reinforced components throughout its suspension systems, including all bearings. Spring and shock absorber settings are firmer than on the 911 Turbo. In the front, the damper struts use threaded spring plates that provide adjustable height and fine-tuning for racetrack driving. Uniball joints on the strut support mounts minimize axle kinematics when the springs are compressed and also allow wheel camber adjustments needed for using racing tires.
For more precise spring and shock absorber response, the multilink rear suspension substitutes metal bushings for the rubber bushings used in the 911 Turbo. As in the front, threaded spring plates provide height adjustment. In addition, the rear anti-roll bar features four adjustment settings.
Widest Porsche Tires Ever
The Porsche 911 GT2 employs larger wheels and tires than even the 911 Turbo. The front alloy wheels measure 18 x 8.5-inch (vs. 18 x 8.0-inch for the 911 Turbo) and mount 235/40 ZR18 tires (225/40 ZR18 for the 911 Turbo). The rear alloy wheels measure 18 x 12-inch (18 x 11-inch for the 911 Turbo) and mount super-wide 315/30 ZR18 tires (295/30 ZR18 for the 911 Turbo).
Instead of a spare tire, the GT2 comes with a tire repair kit, saving 29 lb. (13 kg) and also adding some luggage space. The kit includes a bottle of tire sealing foam, an air compressor and a pressure gauge.
Ceramic Composite Brakes
The 911 GT2 is the first Porsche sportscar to be fitted as standard with the Porsche Ceramic Composite Brake (PCCB) discs. The ceramic composite discs weigh 50 percent less than comparable metal brake discs, reducing unsprung weight by a significant 36.6 lb. (16.6 kg) and thus enhancing suspension response. In conjunction with a new type of brake lining, these ceramic brake discs immediately build up very high and consistent friction throughout deceleration. Yellow-painted brake calipers tip off the presence of the PCCB system.
The PCCB system provides optimal braking performance even under extreme conditions, on dry or wet roads. An extremely hard disc surface and immunity from salt corrosion give the PCCB discs a long service life. Porsche designed ducting in the front apron and in the rear quarter panel air intakes to direct additional cooling air to the brakes.
No Compromise on Safety
While reducing weight of the GT2, Porsche in no way compromised the basic integrity of the structure, nor was any safety technology from the 911 Turbo deleted. A patented crumple zone body structure protects a reinforced passenger compartment. On all Porsche models for 2002, the three-point inertia-reel seatbelts add new pretensioners and load limiters. The trunk includes an anti-entrapment internal release handle, a feature that was added to all Porsche models for 2002.
The GT2, like all Porsche models for 2002, is equipped with dual front airbags plus the Porsche Side Impact Protection System, which includes boron-steel door reinforcement beams, energy-absorbing door panels and door-mounted side airbags. The 30-liter capacity sidebags provide additional protection for the chest, head, and pelvis.
Light but Not Spartan
Although Porsche has sacrificed some luxury features to reduce weight in the GT2, the car is still suitable for everyday driving. Special leather sport seats replace the standard 911 seats, and provide optimal side support along with excellent comfort on long distance drives. Deletion of the rear seats saves 17.6 lb. (8 kg).
While Porsche has reduced the weight of the GT2 in comparison to the 911 Turbo, standard equipment includes power windows and an anti-theft system with immobiliser, transponder key, alarm and central locking with remote entry. The Porsche 911 GT2 substitutes an in-dash CD radio for the Bose digital sound system used in the 2002 911 Turbo. Automatic climate control with an activated carbon filter and cruise control are available as options, as is natural leather trim in dark gray or brown.
A New Chapter In Porsche Turbo History
Porsche began using turbochargers in the 917 racecar in the early 1970s and introduced its first 911 Turbo model in 1974. The 911 Turbo arrived in the United States for model-year 1976, and with its 234-horsepower engine (U.S.-spec) could achieve zero-to-60 miles per hour in under six seconds.
Porsche introduced innovations that increased the reliability of turbocharging, including the exhaust wastegate to regulate boost pressure and intercoolers to reduce the temperature of the compressed intake air. Porsche pioneered the all-wheel drive supercar with the limited production 959 of the mid-1980s. Although not imported to North America, the turbocharged 959 became a Porsche legend and paved the way for the first standard-production all-wheel drive Porsche 911 Turbo, which arrived in the U.S. for 1996. The new-generation 911 Turbo arrived for MY 2001, and the Porsche 911 GT2 is based on this car.

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