Guide: Porsche 911 3.6 GT3 (996.1)
Background
For the 1998 one-make Supercup championship, Porsche introduced a new 996-based racer dubbed the 911 GT3 Cup.
The original road-going 996-type 911 had been launched in rear-wheel drive Carrera Coupe form at the Frankfurt Motor Show in September 1997. With its bigger bodyshell and water instead of air-cooled Flat 6 engine, the 996 represented arguably the most significant revamp in the 911’s 34 year history. A Cabriolet arrived at Geneva in March 1998 followed by a four-wheel drive Carrera 4 in July.
Twelve months after the GT3 Cup had broken cover, a street version of the GT3 was unveiled at the Geneva Motor Show in March ‘99.
The GT3 road car was conceived as a spiritual successor to the illustrious line of Carrera RS variants that had intermittently been around since late 1972. Like most Renn Sport 911s, the GT3 would also serve as a homologation special; in this case it would pave the way for a Grand Touring class racing car, the GT3 R, the first examples of which appeared at pre-qualifying for the Le Mans 24 Hours in May 1999.
With on-track success of primary concern, Porsche Motorsport handled much of the GT3’s development. This work most notably focused on the creation of a normally aspirated Flat 6 engine derived from Porsche’s twin turbocharged 911 GT1 unit.
A limited run of 1400 GT3s to be completed by the end of 1999 was announced at the car’s launch in Geneva. However, this initial allocation sold out within two months and the GT3 ultimately proved so popular that nearly 500 extra cars had to be manufactured to satisfy demand.
In addition to its popularity with customers and road testers, the GT3 became the dominant car in its class on track. It was approved for competition use by the Le Mans governing body (the Automobile Club de l’Ouest) almost immediately and subsequently homologated for the FIA’s N-GT class on March 1st 2000.
Unfortunately, like all of Porsche’s RS-badged models, the GT3 was originally outlawed from sale in North America on safety and emissions grounds.
Chassis
The starting point for each GT3 was the stiffer, reinforced galvanised steel bodyshell from the 996 Carrera 4 Coupe. To this, new mounting points were added for the engine and gearbox.
The existing MacPherson strut front and multi-link rear suspension was retained albeit with repositioned suspension pick-up points. Shorter, firmer springs dropped the ride height by 30mm. New sports-tuned Bilstein dampers and anti-roll bars were fully adjustable.
Uprated front wheel bearings were also installed.
As for the braking system, 330mm diameter cross-drilled and ventilated discs were fitted all round (up from 318mm front and 299mm rear for the standard 996 Carrera). The four-piston aluminium monobloc Brembo calipers were shared with the rest of the 996 range but now came finished in high gloss red paint.
The Bosch M5.3 anti-lock brake software was re-tuned.
Only one variety of wheel was available for the GT3: the ten-spoke split-rim SportDesign type manufactured by BBS. These 18-inch diameter wheels were 8-inches wide up front, 10-inches wide at the back and originally came shod with Pirelli P Zero tyres. 5mm wheel spacers were fitted at either end.
The existing power steering system was retained.
Left-hand drive GT3s came with a long-range 89-litre fuel tank but right-hand drive cars originally came with a smaller 64-litre unit.
Engine / Gearbox
The GT3’s party piece was its all bells and whistles Type M96/76 engine which, unlike the regular Carrera motor, was derived from the Hans Mezger-designed GT1 power unit.
Compared to the 3.4-litre Flat 6 fitted to the 996 Carrera, the GT3 engine had 4mm bigger cylinder bores (100mm) and a 1.6mm shorter stroke (76.4mm). Displacement was 3600cc which represented a gain of 213cc.
The M96/76 also featured a low friction valve train plus lightweight forged pistons and titanium connecting rods that allowed the engine to rev all the way up to 9000rpm (although it was given a soft redline at 7800rpm). A nitride-hardened lightweight crankshaft with eight bearings was another unique feature.
In order to accommodate the long block Mezger engine in the 996 engine bay, Porsche Motorsport devised a new dry-sump lubrication system with the oil tank mounted on the engine block.
Custom mapped Bosch DME sequential engine management was installed and the compression ratio was hiked to 11.7:1 (up from 11.3:1).
As per the rest of the 996 range, the GT3 engine employed a water-cooled all-alloy Flat 6 engine instead of the familiar air-cooled type utilised by earlier 911s. These engines used dual instead of single overhead camshafts and four instead of two valves per cylinder. A VarioCam dual stage intake system gave the GT3 great urgency above 6000rpm.
With 355bhp at 7200rpm the GT3 was the most powerful normally aspirated 911 ever offered to the public. its torque rating was 273lb-ft at 5000rpm.
For comparison, the regular 996 pumped out 296bhp at 6800rpm and 258lb-ft at 4600rpm.
Whereas Carrera derivatives could be specified with a semi-automatic Tiptronic transmission, the GT3 was only available with a six-speed manual ‘box.
The Getrag G96/90 unit fitted to the GT3 was an updated version of the reinforced unit found in the 993-type 911 GT homologation special. It came with triple-cone synchros on every gear and used steel pieces on second through sixth which offered much greater wear resistance compared to brass components. For this application the gearbox was fitted with a new casing and cable linkage.
Transmission was through a reinforced clutch and mechanical limited-slip differential.
No traction control system was employed and nor was the Porsche Stability Management system.
Bodywork
Externally, each GT3 automatically came fitted with the aero kit that was an option on the regular 996 Coupe. It comprised special front and rear bumper assemblies, deep crossover side skirts and a dual plane rear spoiler mounted on the engine cover.
Uniquely, Porsche further enhanced the GT3 with a discrete lip spoiler under the front apron and a Gurney flap along the trailing edge of the rear spoiler’s lower section.
In addition, the underbody cladding was redesigned and a GT3 badge was added to the engine lid.
Despite its extra downforce-inducing addenda, the GT3 had an identical 0.3 drag coefficient to the standard 996 Carrera.
As per the 1999 model year 996 onwards, clear instead of amber indicator lenses were fitted.
Body panels were steel with the exception of the bumpers, spoilers, sills and mirror housings which were fashioned from plastic composite material.
Interior
To reduce weight, the GT3 came with a simplified interior.
The rear seats used by regular 911s were deleted and the now vacant area carpeted instead.
Sound deadening was much reduced, manual instead of electric mirrors were installed, the lower section of the central control panel was removed and no audio system was fitted.
Underneath the front lid was a space-saver spare wheel.
Single-piece fibreglass-shelled Recaro bucket seats were upholstered with a thin covering of leather and could only be adjusted fore / aft.
GT3 branding was applied to the rev counter, carpeted rear bulkhead panel and sill plates.
The instrumentation was otherwise identical to any other 996 Carrera. In the centre of the five-gauge cluster was a large tachometer flanked to the left by a speedometer and a voltmeter. Off to the right was a combined oil temperature / fuel gauge and an oil pressure dial. Digital read outs at the base of the three main instruments provided the driver with all manner of additional information.
The rest of the switchgear was mounted on the central console along with the ventilation controls.
A three-spoke steering wheel was fitted as opposed to the four-spoke type sometimes fitted to regular 996s.
The list of standard equipment included electric windows, leather upholstery, remote central locking, front and side airbags and an alarm / immobiliser.
Options
Air conditioning and an audio system were no-cost upgrades.
Additionally, customers could choose from a large number of optional extras to personalise their GT3.
Instead of the standard Recaro buckets, Porsche offered the hard-backed two-way electric Sports seats that were available on the rest of the 996 range. The seat backs of both these and the Recaro buckets could be painted if desired.
Many of the interior’s other surfaces could be painted to a customer’s requirements or covered in leather. Wood, aluminium or carbonfibre inserts were available along with coloured seatbelts. The absent centre console could also be re-instated.
Wheel centres were available in any colour.
Paint To Sample was an expensive upgrade and, given suitably deep pockets, practically any level of customisation could be requested through Porsche’s Exclusive department.
Option code M001 was for a GT3 Cup racing version.
M002 was for a standard GT3 street version.
M003 got you a GT3 with Club Sport equipment.
The Club Sport package was another no cost option conceived for those buyers who expected to use their GT3 on track. It comprised a roll cage (which required deletion of the side airbags), fire-proof Nomex fabric for the Recaro seats, six-point Schroth harnesses, an electrical cut-off switch ahead of the gear lever and another under the front lid, a fire extinguisher in the passenger footwell and a single instead of dual mass flywheel to increase engine responsiveness.
Weight / Performance
At 1350kg, the GT3 weighed 40kg less than a standard 996 Carrera Coupe and 95kg less than a Carrera 4 Coupe.
Top speed went from 171mph to 188mph.
The 0-62mph time dropped from 5.2 seconds to 4.7 seconds.
Significantly, the GT3 became the first production car to circulate the fabled Nurburgring in under eight minutes when Walter Rohrl recorded a lap of 7 minutes 56.33 seconds.
2001 Model Year
A handful of late production GT3s crossed over into the 2001 model year and thus came with electric front lid and engine cover release mechanisms and LED interior lights.
These run out models also featured an alcantara headliner, electric mirrors, thicker trunk carpet and improved fluid lines between the engine and radiators.
End of Production
GT3 production was discontinued during the autumn of 2000.
By this time, Porsche had completed 1868 examples, 308 of which were right-hand drive.
A second generation 996.2 GT3 was subsequently unveiled at the Geneva Motor Show in March 2003.
Competition History
In competition, the 911 GT3 R and RS faced stiff opposition from the BMW E46 M3 GTR and Ferrari 360 GT between 1999 and 2003 (after which the 996.2-based GT3 RSR took over).
GT3s had arguably most success in the Le Mans 24 Hours where they won the Grand Touring class on five consecutive occasions: 1999 (Manthey Racing), 2000 (Team Taisan), 2001 (Seikel Motorsport), 2002 (The Racer’s Group) and 2003 (Alex Job Racing).
In the American Le Mans Series, three Team Championships were secured: 2000 (Dick Barbour Racing), 2002 (Alex Job Racing) and 2003 (Alex Job Racing).
Two FIA GT Championship N-GT class Team and Driver titles were secured: 2002 (Stephane Ortelli and Freisinger Motorsport) and 2003 (Marc Lieb and Freisinger Motorsport).
Outside of these major international contests, the GT3 R and RS racked up countless wins at national level.
Text copyright: Supercar Nostalgia
Photo copyright: Porsche - https://www.porsche.com & Supercar Nostalgia
