Porsche 911 991 GT3 3.8 (2013-2015)

Official photos: 2013 March 4
Premiere: 2013 March 5, Geneva motor show
Market launch: 2013 August

 © Porsche

Technical specification and comparison

Modification No. of
seats
Gearbox kW lb-ft Nm 60 mph 100 km/h 100 mph 200 km/h mph km/h kg lb W/lb W/kg Nord-
schleife
2013 911 991 GT3 3.8 2 PDK 7-speed 350 324 440 3.3 sec. 3.5 sec. 7.5 sec. 11.4 sec. 196 315 1430 3153 111 245 7:25
2011 911 991 Carrera S 3.8 WLS 4 PDK 7-speed 316 324 440 *3.8 sec. *4.0 sec.     190 306 1415 3120 101 223  
2011 911 997 GT3 RS 4.0 2 manual 6-speed 368 338 460 3.8 sec. 3.9 sec.   11.9 sec. 193 310 1360 2998 123 271 7:27
2009 911 997 GT3 3.8 2 manual 6-speed 320 316 430 3.9 sec. 4.1 sec.   12.3 sec. 194 312 1395 3075 104 229  
Here year is year of introduction, not model year
* with Launch Control

Before the production of the 991 GT3 started, 14.145 GT3 cars of 996 and 997 generations were made between 1999-2012.

2013 March 5. Geneva Motor Show, 991 GT3 & GT3 Cup launch. Persons featured in the video include Andreas Preuninger, Jacky Ickx and Michael Mauer (Director Porsche Style).

The many questions

The 991 GT3 came with more questions than answers. Why isn't the "lightweight 911" light? Why isn't the manual gearbox available? Why does it have 20" wheels, when it is proven that 18" is optimal for racing use...

Engine

The new 3.8-litre GT3 engine was a technological marvel. As there are rules and therefore restrictions for the racing cars, the street-legal 991 GT3 had more power than the 991 GT3 Cup car. Both had 3.8-litre engines, but the racing variant had 338 kW compared to the street version's 350 kW. The street engine had a rev limiter set 500 revolutions higher, at 9000 rpm instead of 8500 rpm in the Cup car. Although not as powerful, the racing version was naturally much-much lighter.

Engine problem on early cars

Porsche press release from March 19, 2014, said the engines of the first 785 produced 991 GT3 will be replaced by the Porsche Centres. They found the engine could be damaged by the loosened screw joint on the connecting rod, leading to engine destruction and oil getting on hot exhaust which could start a fire.

Gearbox

Even though the GT3 version of the PDK gearbox was 2 kg / 4 lb lighter than the PDK in the Carrera, the car suffered 18 kg / 40 lb weight increase due to the automatic transmission. The PDK came with a "paddle-neutral" feature - if the driver pulled both shift paddles simultaneously, both clutches were opened and the flow of power from engine to real wheels was cut off.

Rear axle steering

The 991 GT3 was 70 kg/154 lb heavier than the preceding 997 GT3 RS 4.0 and to cope with the weight, rear axle steering was used. At speeds of up to 31 mph/50 kmh, the system steers the rear wheels into the opposite direction of the front wheels, between 31-50 mph/50-80 km/h, the rear wheels are not steered and at speeds above 50 mph/80 km/h, the system steers the rear wheels parallel to the front wheels, so the car can easily change lane going sideways.

Tyres

The 991 GT3 was equipped with Dunlop Sport Maxx Race tyres, a new alternative to the Michelin Pilot Sport Cup tyres. The sizes were 245/35 ZR20 (91Y) N0 and 305/30 ZR20 (103Y) XL N0. "N zero" says a tyre is created specifically for Porsche.

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Forged aluminium wheels are lighter and stronger than regular aluminium wheels. Front wheels are 9x20" with 245/35 tyres and rears are 12x20" with 305/30. © Porsche AG
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Red is the right colour for a quick car© Porsche
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 © Porsche
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 © Porsche
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 © Porsche
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A ram-air intake system uses car's speed to force more air into the engine to increase power © Porsche
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Optional clear rear lamps© Porsche
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You can't see the engine in the 991 cars© Porsche
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The exhaust flaps can be adjusted by pressing the button. When the engine is started, the exhaust is in the "going to theatre"-mode, but after the press on the button, the obstacles are removed, the engine makes the noise the GT3 has to make and the torque is increased up to 26 lb-ft/35 Nm in the 3000-4000 rpm range.© Porsche
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In addition to aluminium front fenders, front lid and doors like on 991 Carrera, the roof panel is of aluminium, too© Porsche
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 © Porsche
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The rear end is 44 mm wider than on the 991 Carrera © Porsche
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The adjustable rear wing has been with the GT3 since 1999© Porsche
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License plate lights are also Light Emitting Diodes© Porsche
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 © Porsche
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 © Porsche
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 © Porsche
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Standard heavy-duty brakes can be spotted by the red calipers. Discs are 380 mm front and rear. PCCB was optional. The wheels were platinum-coloured as standard, but could optionally be ordered in silver.© Porsche
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 © Porsche
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The rear axle is equipped with the Porsche Torque Vectoring Plus (PTV Plus) as standard. The system consists of an electronically controlled, fully variable locking rear differential and selective braking interventions at the rear wheels.© Porsche
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The standard fuel tank capacity was 64 liters. A 90 L tank was a no-cost option. This trick is used to get the car's official weight as low as possible. © Porsche
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Optional Martini livery from Porsche Tequipment© Porsche
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 © Porsche
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Optional liveries on the sides and over the car © Porsche
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Full LED headlamps were optional (xenon was standard)© Porsche
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LED headlamps with daytime driving lights on© Porsche
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 © Porsche
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Xenon headlamp with optional cornering lamp function PDLS (Porsche Dynamic Light System), the same lamp in black design and the optional LED headlamp© Porsche AG
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 © Porsche
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991 GT3 is 1.2"/30 mm lower than the 991 Carrera© Porsche
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 © Porsche
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Even though the clutch pedal is missing, such an invitation is super tempting© Porsche
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The cockpit feels a bit "heavy" for a track day car© Porsche
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 © Porsche
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The engine rev limiter is set at crazy 9000 rpm! The titanium-coloured tachometer is equipped with upshift indicator if you happen to use the manual shift mode.© Porsche
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If the car is already as heavy as it is, the rear seats would become handy (when the Clubsport package is not specified)© Porsche
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Clubsport kit and folding bucket seats with integrated airbags. The one-piece Carrera GT bucket seats were not available because they did not have airbags in them. © Porsche
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Standard Sport Plus seats. Optionally available were the adaptive sport seats and bucket seats. The standard seats had electrical backrest and height adjustment, fore/aft was manual.© Porsche
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Touchscreen with MP3-compatible CD-player, universal audio interface and 4 speakers were standard, navigation module optional. The AC system had an automatic air recirculation control with air quality sensor.© Porsche
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The red stitching was optional© Porsche
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In Race Track mode the upshifts occur at higher engine speeds. The PSM included ABS, ESC Electronic Stability Control and Traction Control.© Porsche
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The Clubsport package was available at no extra cost when the bucket seats were bought. The CS package comprised a roll cage behind the seats, a 6-point racing harness supplied ready to install on the driver’s side (passenger side at extra cost), a ready-to-install fire extinguisher with mounting bracket and preparation for battery master switch. Battery master switch and the front part of the roll cage (which was not street legal in some countries) were available from Porsche Motorsport.© Porsche
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The 991 generation saw the first GT3 engine with direct petrol injection. Two fuel pumps generate a system pressure of up to 200 bar. The standard equipment included a more advanced version of the previously optional dynamic engine mounts. They are filled with an enclosed liquid with magnetic particles, which changes in viscosity in the presence of an electric field. © Porsche
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The active rear wheel steering system comprises two electro-mechanical actuators which allow the steering angle of the rear wheels to be varied by up to 1.5 degrees © Porsche
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Standard colours all look very good: white, Racing Yellow, Guards Red / Indischrot (Indian red in German) and deep non-metallic black. Metallic colours are optionally available, but they make the car look like luxury car and not so much as a race car. Some classic special order non-metallic colours would also be stunning, like the Mexican Blue or the 997 GT3 RS green or orange...© Porsche
2013 March 4. Evo Magazine editor Jethro Bovingdon interviews Porsche engineer and High Performance Cars manager, Andreas Preuninger

Article © James Herne / Stuttcars.com


PDF

911 991 GT3 3.8

3/2013 · English

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911 991.1 Tequipment - Zubehör für die 911 Modelle

6/2014 · German

911 Carrera, GT3, 911 Turbo

Aerokit, Carrera S/4S 3.8 WLS, Martini...

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Continue to GT3 4.0 or to 991 GT3 RS 4.0
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