Porsche 911 GT3

Infobox Automobile


name = Porsche 911 GT3
manufacturer = Porsche
production = 1999-present
assembly = Leipzig, Germany
body_style = 2-door coupe
layout = RR layout
class = Grand tourer /
Sports car
transmission = 6-speed manual
wheelbase = Auto in|92.7|0Infobox Automobile generation
name = 996


production = 1999-2005
engine = 3.6L 380 hp H6
length = Auto in|174.6|0
width = Auto in|69.7|0
height = Auto in|50.2|0

Infobox Automobile generation
name = 997


production = 2007-present
engine = 3.6L 415 hp H6
length = Auto in|174.3|0
width = Auto in|71.2|0
height = Auto in|50.4|0

The Porsche 911 GT3 was introduced in 1999 as a high performance version of the first water-cooled version of the Porsche 911, the 996, to continue the quarter-century tradition of low-weight RS (short for "Rennsport" in German) models that ended with the 993 RS. The GT3, named after the FIA GT class it was intended for, did not use the rather simple engine of the regular production versions of the 996, but a naturally-aspirated version of the turbocharged Porsche 962 and Porsche 911 GT1 race cars. Later, the turbo-charged Porsche 911 GT2 was added to the maker's lineup, but unlike its predecessor 993 GT2, did not fit into GT racing regulations. The racing versions of the GT3 have won several major 24h races outright, and mainly dominated their class at Le Mans.

Pre-Production history

After winning the 1998 24 Hours of Le Mans overall with the Porsche 911 GT1, Porsche had announced not to enter the 1999 Le Mans with a factory car suitable to defend the overall win against the competition by major automakers due to an internal agreement with Ferdinand Piech to leave the field to the Audi R8. Instead, Porsche decided to focus again on less expensive GT racing classes at the 24 Hours of Le Mans and the Grand-Am Rolex racing series, and began making plans to modify the new 996 generation of the 911. They set out to develop the race car simultaneously with a road-going variant which was required by GT class homologation rules. The car debuted at the Geneva Motor Show in 1999 before going on sale.

Engine and transmission

The engine of the GT3 sets it apart from the other 996 models although it shares the same basic 3.6 liter displacement of the standard 996 type so-called "integrated dry-sump" flat-six engine. It is actually based on the original air-cooled 911's versatile, true dry-sump crankcase, with an external oil tank. The original version of the GT3 had Auto PS|360|0, compared to the Auto PS|300|0 of the regular 996.

In GT3 configuration, this so called "split" crankcase (meaning the parting line of crankcase is on the crankshaft centerline) 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 though a radiator. Thus, the GT3 engine is very similar to the completely water cooled 962 racing car's engine, which is also based on this same crankcase. The 962 differs, however, by using 6 individual cylinder heads while the GT1/GT3, like the air and water cooled Porsche 959, uses 2 cylinder heads, each covering a bank of 3 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 GT3 production, the basic casting used for the crankcase of the GT3 was exactly the same as the air-cooled engine and one could see the "964" casting number on the bottom of the crankcase and areas normally machined in the air-cooled application that are not machined for use in the water-cooled application. The crankcase casting was changed in mid-2004 to a "996" casting number crankcase to eliminate these external air-cooled remnants, but internally it is the same.

This engine gives the GT3 a distinct racing heritage that dates back to the Porsche 904/6 of the mid-60's, up to the Carrera Cup and 997 Super Cup and RSR racing cars of today.

Because the 911 air-cooled crankcase uses the Porsche 356 engine to transmission mounting flange configuration, the GT3 uses a 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 996 type 911 gearbox.

At Convert|415|hp|kW|0|abbr=on, the 3.6 litre flat-six engine in the 997 GT3 and GT3 RS is the most powerful naturally aspirated six cylinder engine in any production car.

Racing

Due to the absence of the official Porsche team in the 1999 24 Hours of Le Mans, only privateers with the nearly obsolete air-cooled 993 GT2 Turbo were expected to represent the marque, with few chances to beat the Chrysler Viper for GT2 class honors (or GTS as it was called in Le Mans that year). Yet, two new race versions of the water-cooled 996 showed up, officially entered in the GT3 class by private teams, but the drivers involved and Porsche engineers in the pits indicated that it was an effort backed by the company. Even though these were the least powerful cars in the event, being the only entrants in the GT(3) class, the new GT3-R was noticed by fans for its loud exhaust sound when driving in 1st gear through the pitlane, comparable to ex-Formula 1 engines of Judd. The better of the two cars, entered by the German Manthey team, finished 13th overall, beaten by only two of the Vipers with an engine more than twice as big.

The 996 GT-R were made available to privateer teams. In the 24 Hours Nürburgring of the year 2000, a factory-backed effort of the local Phoenix team managed to beat the Zakspeed Chrysler Viper that dominated this race from 1999 to 2002. The improved 996 GT3-RS version of 2001 was entered in countless races in the years to follow, scoring not only many class wins, but also overall wins at Daytona and Spa in 2003. In 2004, the 996 RSR was made available, with numerous improvements to the RS, including a sequential gearbox, which allows for faster gearshifts.

In 2005, the new 997-generation racing vehicles began to debut with the GT3 Cup, and was followed by the launch of the 911 GT3-RSR at the 2006 Spa 24 Hours. In VLN endurance races at the Nürburgring in 2007, the new car had teething problems, and the wide rear fenders reduced top speed. Yet, the Manthey entry won the last 4h race before the 24h event, and managed to win the big event also.

The following race versions were or are offered:
* 1999 996 GT3-R
* 2000 996 GT3 Cup [ [http://www.porsche.com/usa/eventsandracing/motorsport/racingcars/996gt3cup/] ]
* 2001 996 GT3-RS
* 2004 996 GT3-RSR - with sequential gear box [http://www.porsche.com/usa/eventsandracing/motorsport/racingcars/996gt3rsr/]
* 2005 997 GT3 Cup [http://www.porsche.com/usa/eventsandracing/motorsport/racingcars/911gt3cup-997/]
* 2007 [http://www.racecar-engineering.com/allarticles/184232/porsche-911-gt3-rsr.html 997 GT-3 RSR] [http://www.porsche.com/usa/eventsandracing/motorsport/racingcars/911gt3rsr-997/]
* 2008 997 GT3 Cup S [http://www.porsche.com/usa/eventsandracing/motorsport/racingcars/911gt3cup-s/]

Apart from numerous class wins, the GT3 won major events overall:
* 24 Hours Nürburgring in 2000, 2006, 2007
* 24 Hours Spa in 2003
* 24 Hours of Daytona in 2003Also, at the Nürburgring, the GT3-RS and modified versions (with 3.9 litre engine) win many VLN races.

The various national "Porsche Carrera Cup" series, and the international Porsche Supercup which is mainly run at Formula 1 events, also use the GT3 Cup.

Road cars

911 GT3 RS

The "Porsche 911 GT3 RS" is a high-performance sports car built by Porsche since 2003.It is often confused with the non-roadlegal racecar Porsche 911 GT3-RS of 2001 and later, which was based on the Porsche 911 GT3-R of 2000.

The RS (short for the German term Rennsport which means "Motorsport" in English) is mainly a carryover of the Porsche 911 GT3, albeit it is lighter thanks to a polycarbonate rear window, carbon fiber hood and rear wing. Porsche ceramic composite brakes, which are also more heat and fade resistant than the iron units fitted as standard, are optional. Mechanically the two cars are identical, and share the same horsepower, and 3.6 litre flat-six engine.

996 GT3

As with Porsche's 911 RS models, the GT3 was devoid of any unnecessary items that would add weight to the car. Sound deadening was almost completely removed, as were the rear seats, stereo system, sunroof, and air conditioning, although automatic air conditioning and CD/radio became no-cost optional add-ons. In addition, Porsche offered a no-cost option called the Clubsport package. This option replaced the standard electrically adjustable leather front seats with manually adjustable racing buckets finished in fire-retardant fabric, bolt-in half-roll cage, 6-point drivers racing harness, fire extinguisher (mounted in the front passenger footwell) & 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.

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 made significant updates to the GT3 for 2004, the first year the car was offered to US customers. Horsepower was raised to Convert|381|hp|kW|0|abbr=on and torque to Auto ftlbf|284|0, 80% of which was available from a mere 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. The new car also was updated to the 2002 911 facelift including headlights that were differentiated from the Boxster. The engine alone costs over 40,000 GBP as a replacement from Porsche due to the cost of the titanium parts.

In track testing by American automotive journals, the GT3 managed a 0-60 mph time of 4.0 seconds and a quarter mile time of 12.3 seconds at convert|118|mi/h|km/h. During skidpad testing the vehicle posted 1.03g. Porsche introduced a revised 911 GT3 RS to the European market in 2003, marking the last revision of the 996 platform car before its discontinuation in 2005.

In 1999, 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. Later, with the 996 GT3 RS, he managed 7 minutes 43 seconds. [ Cited in an interview with Mr. Röhrl by Swedish sports car magazine Automobil 5.06.]

996 GT3 RS

The original Porsche 996 GT3 RS had a production run from 2003 to 2005. The "RS" moniker, and the characteristic blue or red wheels and "GT3 RS" side stickers link the GT3 RS to historically important Porsches such as the Carrera 2.7 RS of the early 1970s.

Automobile magazines claim the GT3 RS can accelerate from 0-60 mph in about 4.3 seconds, maintain over 1.0g on the skidpad, and have a top speed of around Auto mph|190|0 using the 996 GT3's Convert|380|hp|kW|0|abbr=on engine.

997 GT3

In February 2006, Porsche revealed the latest street-legal version of the GT3, now built on the new 997 platform. Prior to that, 997 had already been in active race use for several months. In addition to a new, Convert|415|hp|kW|0|abbr=on 3.6 litre flat-six engine the vehicle features "zero lift" aerodynamics, meaning the car creates only aerodynamic downforce but no "lift", which pulls upwards and away from the road surface and affects overall grip. The vehicle now makes use of a modified, track oriented version of Porsche's active PASM suspension making this the first of Porsche's RS or GT3 versions to feature an electronically adjustable suspension system. Also available are a navigation system and Porsche's "sports chrono" gauge package, making this the most "friendly" lightweight track car the company has ever produced. The car went to sale in summer of 2006 and had a starting price of 106,000 USD. The RS was released in Europe in October 2006 and in North America in spring 2007.

Although independent track testing has yet to be performed, it is thought that the vehicle should be able to go from 0-60 mph in under four seconds (Road and Track produced a 3.9 second time with the heavier, less powerful 997 Carrera S) and hit a top speed approaching 320 km/h (200 mph); Porsche's factory performance claims indicate a convert|193|mi/h|km/h|abbr=on top speed and a 0-60 mph time of 4.1 seconds (these figures, like most of Porsche's, are probably modest).

Porsche's official test-driver Walter Röhrl completed the Nürburgring Nordschleife in 7 minutes 42 seconds with the 997 GT3. Cited in an interview with Mr. Röhrl by Swedish sports car magazine Automobil 5.06.

997 GT3 RS

As with earlier models, such as the legendary Carrera RS 2.7 of 1973 and the Type 964 911 RS of 1991, Porsche offered an RS version of the 997 GT3. In common with its predecessors, it provides a homologation model for use in a range of racing series.

Thanks to a close-ratio six-speed transmission with a single-mass flywheel and Auto kg|20|0 lower vehicle weight, the engine revs up even more freely, thus enabling the 911 GT3 to sprint from zero to 100 km/h (62 mph) in 4.0 seconds. That's one tenth of a second faster than the GT3. And it takes 13.3 seconds to hit 200 km/h (124 mph). Maximum speed is 310 km/h (187 mph).

One characteristic of the new RS is the body, which is Auto mm|44|1 wider at the rear (a legacy from the Carrera 4 models with which it shares its shell) by comparison with the 911 GT3. The muscular-looking rear end conceals a wider track that not only improves directional stability but also increases the potential cornering grip of the two-seater coupe. On the other hand, drag is increased, and top speed reduced.

Despite its specialized body, the RS is Auto kg|20|0 lighter than the GT3, weighing in at Auto kg|1375|0. This weight-saving was achieved by the use, amongst other solutions, of an adjustable carbon fiber wing, the use of a plastic engine cover and a lightweight plastic rear window. As a consequence, the corresponding engine power to curb weight ratio is over Auto bhp|300|-1 per tonne.

In addition to the new technology featured in this flat six motor car, the paint scheme and body panels are all designed specially for this car. For the RS version, the limited edition orange color was mixed specially for this car.

For USA RS, no plastic rear window was installed, USA versions of the GT3 and RS have 911 fuel tank and not the larger Euro fuel tank.

References

External links

* [http://www.porsche.com/uk/models/911/911-gt3/ The Porsche 997 GT3 at the official Porsche website]
* [http://www.911uk.com GT3 Owners and information]
* [http://www.racecar-engineering.com/allarticles/184232/porsche-911-gt3-rsr.html Racecar Engineering on the racing versions]