The Type 997 GT3 family, from left to right: GT3 Cup Race Car, GT3, GT3 RS, and GT3 RSR Endurance Race Car
The GT3s are the low volume 911s, road-going production cars homologated for what was Group 3 competition. The original homologated 911 was of course the famous RS 2.7 in 1972. After that Porsche concentrated on the higher Groups for which the 930 Turbo served as the homologation model. In the 1980s, Weissach’s focus was on sport racing cars and Group C and it was only in 1991 that a new 911 RS appeared. This was the 964 RS designed to qualify the Porsche 964 for the Porsche Cup series in Germany. This became the Carrera Cup and over thirty years has expanded into the largest one-make race series in the world. As the 964 gave way to the 993, an RS version appeared in 1995.
Type 996 GT3
The first GT3 was revealed in 1999, once again a limited run to qualify the race credentials of the latest 911, the 996. However, the GT3 was significantly different from its RS forebears: it was not lightened, though its chassis underwent considerable modification, and for the first time, it did not use the 911 production engine. Porsche knew that the new fluid cooled M96 engine of the 996 which effectively had a wet sump (although its marketing people talked about an ‘integrated dry sump’) would experience oil starvation at lateral cornering forces exceeding 0.7g. This would convey entirely the wrong image of Porsche said then engineering director Horst Marchart who commissioned engine builder Herbert Ampferer to create a suitable race engine.
Rather than try to reinvent the wheel, Ampferer saw the GT3 engine as an extension of the competition motor that Porsche was developing for GT1. He took the aluminium block of the 964/993 and grafted a water cooled 24-valve head on to it, the capacity increased from the GT1’s 3.2 to 3.6 litres. This would be an expensive unit to build, but by making it the basis of the yet to be introduced 996 Turbo, its costs could be amortised over thousands rather than hundreds of units.
Often referred to as the ‘Mezger’ engine, the name is something of a misnomer as although the bottom end dated from that era, indeed some blocks even had ‘964/993’ stamped on them, Hans Mezger who retired in 1993 had nothing to do with this engine. Indeed in his memoirs he observes that if Porsche had heeded his advice, Zuffenhausen would never have designed the M96 the way it did and thereby avoided the need to design a separate engine.
Given it was still constrained by limited budgets Porsche was surprisingly generous in the deployment of exotic materials in this special flat six: the forged steel crankshaft had plasma-nitrided surfaces and titanium connecting rods operated aluminium pistons in Nikasil bores. The head had a separate casing carrying the camshafts and tappets made from a standard aluminium alloy (9% silicon, 3% copper).
The head itself used a special heat-resistant alloy 5% copper, 1,5% zinc and trace elements of antimony, cobalt and zirconium. Engine coolant travelled through an oil/water heat-exchanger on the crankcase and four scavenge pumps, one in each cylinder head and two in the sump circulated the oil through the engine and to a separate reservoir.
The GT3 engine featured a more accurately monitored Variocam mechanism. This controlled the camshaft hydraulically instead of the 996’s separate chain between the camshafts which used a tensioner to vary its slack, shortening or lengthening the drive and advancing or retarding the intake camshaft as commanded by the ECU.
The GT3’s 355bhp (360PS) at 7200rpm the road-going was in almost the same state of tune as the R and Cup track versions, the only visual difference under the engine cover, a proper air filter box instead of competition paper filters.
The phase two 996 GT3 was built between 2003-4. Acclaim for the original GT3 was such that Porsche’s board allowed it to become a production model, rather another ‘homologation special.’ The 3.6 was subject to a thorough reworking to permit greater engine speeds: longer, lighter connecting rods and pistons and smaller diameter tappets allowed maximum revs to rise from 7800rpm to 8200rpm with maximum power, now 376bhp achieved at 7400rpm and torque boosted from 370Nm to 385Nm, still at 5000rpm.
Revised Variocam geometry ensured the GT3 met both Euro 4 norms and EPA standards which made this GT3 the first “factory tuned”911 which could besold legally in the US since the 911S of 1972.
Type 997 GT3
The next GT3, the 997 arrived in 2007. Incremental improvements – lower reciprocating mass, compression raised to 12.1:1 and a new induction system contributed to a power output of 411bhp at 8400rpm, almost 115bhp/litre and unprecedented in a road car. Porsche nonetheless claimed that the engine was safe to 9500rpm which gave weekend racers some margin for error.
The second generation 997 GT3 was an opportunity which Porsche took to build the homologation version of the race engine it had been campaigning with the 996 RSR. Bored out to 3797cc, with a still higher compression ratio, this raised power output to 430bhp.
Then in 2011, as a proverbial last hurrah, the ‘Mezger’ was expanded to 4 litres for the 997 RS 4.0 and an eye-catching 500PS (495bhp) rating. Eagerly awaited, the 600 RS 4.0s were practically sold out before they even came off the production line.
Porsche 996/997 Buyer’s Guide
What To Look For
history is never more vital than with the GT3. Potential purchasers need not be put off by a car with significant circuit mileage, but in that case, it needs evidence of the more intensive maintenance regime Porsche recommended. More frequent engine oil changes for example and brakes fluid and coolant replacement as well as fresh oil in the gearbox at the end of a track season.
All these engines were built for racing and a car that has been tracked, but properly looked after will often run better than a very low mileage GT3 which because of infrequent use may not always have been serviced annually, but the track car will show more wear. Oil weeps, rarely significant, can occur around the timing chain housing and coil packs can expire, especially when exposed repeatedly to road filth, but considering their output, the ‘Mezger’ GT3 engines are extraordinarily rugged.
For most drivers it is too uncompromising as daily transport, and generally few 996/997 GT3s will have covered more than 80,000 miles, but the engines do last if systematically and proactively looked after as French owner, Luc Lecudonnec, has proved: he told Flat 6 he bought his 997 GT3 3.6 new in 2007 and has regularly toured 20,000 miles pa, driving to track days in UK, Germany and Portugal.
Apart from breaking a pinion at 100,000miles, which required a new transaxle, his GT3 has never let him down and at 266,000 miles, he still sees no reason to change it. For peace of mind, he had the engine rebuilt 5000 miles ago. He adds he always warms the car up carefully and, on the track, drives cooling down laps and that with the GT3 he avoids short runs and town traffic.
The 996/7 GT3s all used the Getrag six-speed gearbox of the previous 993. The throw was shorter and the lever feels heavier than the equivalent Carreras. A firm, decisive movement to change ratios is required and combined with a heavy clutch, it simply underlines the more demanding nature of the GT3. A limited slip differential was standard throughout.
For the 997 generation, Porsche softened the lockup from 60/40 to 60/28 to improve straight line stability and the 997’s gearbox had slightly lower ratios reflecting the standard 19” wheels and higher-revving ability. But with up to 110mph available in third, enthusiasts continued to complain that with engines whose maximum torque came at 6000rpm and peak power 2000rpm beyond that (996 figures are about 500rpm lower) the ratios were still too high.
Steven McHale, formerly technical director of JZM, GT3 specialists in London used to tell track devotees that a simple way to improve the responsiveness of their GT3s was to lower the final drive ratio which had the effect of lowering all the gears. “Porsche was obsessed with top speed, but you don’t need a 190mph capability on most circuits.”
The 996 GT3s had no electronic limiting beyond ABS, but Porsche sensibly decided to introduce traction control for the 997. This could be switched off in two stages should the driver choose. In keeping with the essentially mechanical nature of the 996/7 GT3, there was no automatic gearbox option: Porsche would save the PDK for the next GT3 generation, the 991 GT3. As a rule, the road going GT3s all had dual mass flywheels. but the Clubsport and RS variants single mass items, the lack of flywheel inertia making them harder work in traffic.
What to look for: the Getrag is a famously robust unit, but a very heavy clutch is a sign that the plates are worn and it needs replacement. On a properly used GT3 the clutch works hard and for a car showing 70,000 miles, it may have been replaced at least once if not twice. Listen for any untoward noises from the limited slip differential during parking manoeuvres which might suggest it is past its best. Like the clutch this is also a component which can wear out.
The first GT3 sat 30 cm lower than the Carrera and featured stiffer, adjustable roll bars, thicker springs and firmer damping. Harder bushing removed some of the self-correcting tendency of the Carrera leaving more responsibility in the driver’s hands. Hubs and suspension mounts were also strengthened.
Unlike the engine, there were no significant changes to the suspension for the second-generation car, but for the GT3 997, Porsche brought in electronics: PASM allowed the suspension to be softened slightly making touring less uncomfortable – the GT3 996’s ride is fatiguing on indifferent roads, as well as stability management. Front suspension geometry was modified to accommodate a new generation of high-performance tyres and for the first time, carbon ceramic brakes were an (expensive) option.
What to look for: some GT3s may have aftermarket modified suspensions. These usually reflect a previous owner’s track bias and prove less suitable for the road. The consensus is that as with most things Porsche, the factory set up is the best compromise.
The original GT3 used the stock Carrera body with a deeper front valance. Side skirts and a double-wing spoiler combined with the reduced ride height to produce a rather more aggressive-looking 911; Porsche subsequently sold several hundred GT3 body kits to Carrera owners keen to have this look for their 911s, Subtle adjustments to the front and rear profiles were made for the second-generation car which now had a single-blade wing.
At the end of production in 2004, the Motorsport department created an RS version of which 682 were built by which time all 996 GT3 components had been used up. Designed to homologate the 911RSR, the RS used the more rigid Carrera 4 body and had a deeper front splitter and substantial rear wing. The rear window was acrylic and carbon fibre used for front and rear body panels. With the Cup manifold, the 3.6 made some 400bhp. The 996 RS which saved about 50kg over the plain GT3 was very marginal as a road car, but it demonstrated a third variant, adding to the Comfort or Clubsport choice.
The 997 GT3 appeared in 2006 by which time the 997 range was well established. Once again it featured specific front and rear treatment, including a wide and now adjustable rear wing as well as side skirts. A year on and an RS version appeared. This used the visibly wider Carrera 4 body together with an altogether more sophisticated-looking carbon fibre aero kit. Race bred said Porsche with appropriately increased downforce figures, the carbon fibre body offered a worthwhile 20kg weight saving, more than cancelling out the penalty of the heavier widebody.
The second generation GT3 RS, the 3.8 was built on the same basis with a similar weight saving, but this time with a 15bhp uplift over the base GT3. A slightly symbolic increase, it showed that Porsche had not been entirely deaf to complaints that the 3.6 GT3 RS cost almost $20,000 more than the GT3 with the same power output.
What to look for: many GT3s will have been driven on the track, no drawback as Porsche intended them for this, but does means that plenty of cars will have slid off and incurred damage hitting barriers. Front and rear bumpers are readily if expensively replaceable and should not be a reason to discount them. However, buyers should also look out for signs of greater impacts which might have affected the chassis: the carpets need to be lifted to see whether the floors have been welded, or display creases, or other evidence of major accident repair. Repainted areas where the car originally would not have had the shiny topcoat is another sign of past damage. Corrosion in unexpected places is another reason to be wary.
The GT3’s cabin was nothing if not business like: as with the air-cooled RSs, a carpeted rear cabin with no passenger accommodation and in front, sports seats for driver. This was the ‘Comfort’ specification, a distant descendant of the original RS 2.7 Touring. For the same price, the buyer could specify the ‘Clubsport’ cabin, a track-oriented variation which brought flame-proof covering for the seats, a six-point harness for the driver and omission of side airbags.
A half roll cage completed the transformation and air conditioning was a non-cost option. For the 997 GT3, the cabin made much use of Alcantara and the Clubsport version added a half roll cage, fire extinguisher, fittings for a full driver’s harness and a battery master switch. North American buyers were alas not allowed to avail of some of these non-cost options and a sunroof was mandatory.
What to look for: the finishof the 997 cabin is notably superior to the 996’s, now almost 20-year- old cars, whose plastics have not always aged well.
The 997’s Alcantara is another material which unlike leather cannot conceal wear: the pile of the driver’s seat for example can become flat and tired looking. The Clubsport interior is distinctly uncompromising: while the roll cage improves the rigidity of the body, it is mildly obtrusive and impedes luggage access to the rear compartment and really is the choice only for the track devotee.
The GT3 is not a typical 911 and a potential purchaser needs to be aware that a GT3, particularly from earlier generations is far more demanding than other Porsches. What can appear to be a 911 usable on a regular basis often turns out in practice to be rather less convenient. The GT3 is not temperamental, but at slow speeds it feels heavy, which will not surprise anyone used the 993 and the clutch can be a chore in traffic. Ride too can be unpleasantly harsh on broken black top.
Such caveats aside, many GT3 buyers will know what they are taking on: among series production cars, the GT3 had few if any rivals, a car as capable on the track as it is on the road and none of which displays the same long-term reliability. This is worth reiterating: in the 2000s, perhaps only two or three competitors with naturally aspirated engines could claim the 105-115 bhp/litre output of the 997 GT3 (and none today) yet offer track-level performance day-in day-out, provided of course the owner stuck to a systematic, but not onerous maintenance regime and had the budget to sustain it.
Although today’s 992 GT3 would leave the 996/997 versions in its wake, the essential appeal of these first generations is in their distinctly analogue, you might even say vintage nature – sturdy manual gear shifting, hydraulic steering assistance and limited electronic catch fencing (or none with the 996) leaving much to the driver’s judgement. The adage, it’s not how fast you drive, but how you drive fast, comes to mind.
These early GT3s offer a surprising range of choice, but for the buyer who wants to drive his or her GT3 on a regular basis, some models are more practical than others. Two cars, the original 996 RS and the final 4.0 RS because of their low volumes have become collectors’ cars; the first 996 GT3s from 1999-2000, often described by advertisers as hand-built, were relatively undeveloped, simply homologation cars, says Andreas Preuninger, head of GT cars at Weissach.
The 996 GT3 2nd gen was better resolved, but its uncompromising, bone-hard ride counts against it. The 997 3.6 and 3.8 both offer superior performance and the better handling which came from the larger 19inch wheels and improved chassis. While firm, their suspensions are more acceptable on everyday roads. With their aero kits and vulnerable spoilers, the RS versions are rather more suited to the track than the car park at the country club.
An alternative for any would-be purchaser tempted by a 997 GT3, but still uncertain, is to consider the 997 GTS, another 400 horsepower 911: this is easier-going than the GT3, demanding (as any 911 is) if you insist, but also more serene when you have had enough. Many GT3s will have had half a dozen owners, purchasers who simply underestimated this Porsche and moved it on. But for the diehard driver, only the GT3 will do: raucous, unyielding, even ornery on occasion, but incomparable: its vivid acceleration as the engine climbs from 4000-8000rpm, steering demanding absolute commitment from its driver and a soundtrack unsullied by special effects or environmental shackles make the 911 GT3 an extraordinarily dynamic travelling companion.
Porsche 996/997 GT3 Specifications
997 4.0 RS
Bore & Stroke
Power & Torque
*996.2 figure includes 682 RS
**997.1 figure includes 1909 RS
***997.2 figure includes 1619 RS
Important Specs Of Each Model Type
2000-2001 GT3 (aka 996.1 GT3)
Engine: 3.6L Flat-Six HP: 355 Torque: 273 lbs-ft Curb Weight: 2,976 lbs (manual) Length: 4,435 mm (174.6 inches) 0 to 60 MPH: 4.8 seconds ¼ Mile: 12.7 seconds Original MSRP: $122,500 (estimated, sold in Europe only)