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GT3 mk1

Launched in 1999 to homologate Porsche to compete in the new FIA GT series, the Porsche 911 GT3 featured a handbuilt 3.6-litre, flat-six cylinder engine, using the same engine block derived from the Le Mans-winning GT1. It produces 360 bhp (100bhp per litre) and employs lightweight motorsport components including titanium connecting rods and a plasma nitride hardened crankshaft with eight main bearings. The Mk1 GT3 redlines at 7800rpm and had a 2 stage Variocam system.

The gearbox was taken from the 993GT2 with revised gear ratios and used brass synchro rings. Standard wheels were split rim "Sport Designs" and were sized 18x8J (front) and 18x10J (rear) wearing standard 225/40-18 (front) and 285/30-18 (rear) tyres sizes.

The car was available in either in standard (Comfort) or Clubsport spec. Clubsport spec included a factory roll cage, single mass flywheel, nomex bucket seats, side airbag delete, electrical cutoff switch, and for later dealer fitting the front section of the roll cage and a fire extinguisher were also supplied. The Comfort spec included side airbags and the option of leather Recaro bucket seats.

The Mk1 used 4pot calipers (same as 996 Turbo) clamping 330mm discs (front and rear). Visually the GT3 Mk1 has a curvy rear wing and the earlier shaped headlights.

The Mk1 tipped the scales at 1375kg. 106 RHD Mk1s were handbuilt at the Weissach Motorsport factory.

GT3 mk2

Launched in 2003, the Porsche 911 GT3 mk2 features the same basic engine as found in the Mk1. It produces 381bhp or roughly 105bhp per litre - additional power gains over the Mk1 were through the use of reprofiled cams and lighter weight components to provide a higher redline limit of 8200rpm. The Mk2 introduced e-Gas fly-by-wire throttle, and also continuous Variocam.

The Mk2 gearbox was modified and adopted a splash oil cooler in addition to steel synchro rings on 1st, 2nd and 3rd gear. The front track of the Mk2 was widened over the Mk1, and standard wheels were one piece cast wheels and increased in width to 18x8.5J (front) and 18x11J (rear) wearing 235/40-18 (front) and 295/30-18 (rear) tyre sizes.

The car was again available in either in standard or clubsport spec. Clubsport spec included a factory roll cage, nomex bucket seats and for later dealer fitting the front section of the roll cage and a fire extinguisher were also supplied. On the mk2, both specs included a dual mass flywheel.

The GT3 mk2's rear wing is more of a tea tray flat arrangement (in comparison to the mk1). Combined with a unique front apron, the GT3 mk2 achieves a drag coefficient of Cd 0.30. The mk2 featured the newer shape headlights as first seen on the 996 turbo,

The brakes on the GT3 mk2 feature six-piston callipers and larger 350mm front discs fitted with Porsche-patented cooling ducts. Porsche Ceramic Composite Brake (PCCB) discs, standard on the 911 GT2, were available as a cost option.

The Mk2 weighed in at 1425kg. A total of over 300 RHD Mk2 GT3s were produced from Zuffenhausen.


The 911 GT3 RS was based on the Mk2 GT3 and released as a homologation model, manufactured to allow Porsche to compete in international GT racing with revised suspension mounting points over the Mk2. Around 200(?) were built.

The power to weight ratio is 4% better than the basic GT3, thanks to a weight saving of 50 kg - it tips the scales at 1,360 kilograms with a full load of fuel of 90 litres (LHD models) in the tank.

The RS, like its motor-sport predecessors, is only available with a full roll-over cage installed (front section can be removed). All cars have a white paint finish, with the inscriptions only in blue or red.

The road version of the GT3 RS features a special weight-saving rear window made of polycarbonate material and a carbon-fibre reinforced bonnet, rear wing and wing mirrors.

An air collector located under the rear wing uses pressure build-up there to supply extra intake air to the engine at high speeds, so that the RS reaches its maximum power output even more easily than the standard GT3. Between the engine and the gearbox the RS has a single-mass flywheel with a lower rotating mass than the double mass version.

The RS has a slightly different specification engine to the GT3 (M96/79 for the GT3 and M79/80 for the RS).

Porsche said:
The engine of the 911 GT3 is used in the 911 GT3 RS in model year 2004. The geometry of the inlet ports in the cylinder head have been optimised. This resulted in a new engine type, which for this vehicle is designated M79/80.'


GT3/GT3RS Differences

  • Engine (as above)
  • Single mass flywheel
  • Polycarbonate rear window
  • Carbon fibre mirror surrounds
  • Carbon fibre bonnet
  • Carbon fibre rear wing
  • Stiffer dampers
  • Progressive springs
  • Redesigned wheel carriers
  • Lightweight wheels
  • Ram air intake
  • Adjustable uniballs
  • Front and rear adjustable control arms


Engine M96/76 B 6 and M79/80 (RS)
Engine Location Rear , longitudinally mounted
Displacement 3.6 litres
Valvetrain 4 valves / cylinder, DOHC
Fuel feed Bosch Motronic ME 7.8 Fuel injection
Aspiration Naturally Aspirated
Gearbox 6 speed Manual
Drive Rear wheel drive
Electronic Aids ABS only



...please feel free to fill in the gaps...


...please feel free to fill in the gaps...