White Lightning!

The origins of the 1998 Porsche 911 GT1 Le Mans winner can be traced back to a roadgoing version of the Group C 962 launched five years earlier. In order to homologate the 911 GT1/98, the FIA required a single street legal version of the race car to be made. You could call it ‘White Lightning’ because this road legal version of the race car had a top speed of 193 mph (310 km/h), thanks to its race bred 544 bhp (406 kW), 3164 cc flat-six engine. But in order to get to grips with this street version, you need to take a step back and explore the background of the racing version, and understand how and why the GT1 came about in the first place.

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The 1994 Le Mans 24 Hour race was won by Mauro Baldi, Yannick Dalmas and Hurley Haywood driving a Porsche 962 LM GT. But that wasn’t just any old 962 that had been pulled out of the Museum, dusted off, upgraded and prepped for the race in the hope that it might do well. The car that won Le Mans in ’94 had in fact started out as the Dauer 962 Le Mans GT road car that Norbert Singer saw at the 1993 Frankfurt Motor Show.

Porsche did not have a race car with which they could win Le Mans in ‘93. Their only racer was the 911 Carrera RSR 3.8 which was a GT class contender. The cogs of creativity began to turn in Singer’s very fertile mind, and soon a plan was hatched to use the Dauer 962 Le Mans GT road car as the basis for his next Le Mans campaign.

The Automobile Club de l’Ouest (ACO), organisers of the Le Mans 24 Hour race, had shifted their focus away from the prototype era with the Group C racers, and towards GT cars. The Dauer road car was duly completed and registered for street use, thereby qualifying the Dauer 962 LM GT for entry in the ’94 Le Mans which, as mentioned, was won by Baldi, Dalmas and Haywood. “The Le Mans people didn’t really like the Dauer car, but it was to the letter of the regulations, and out of this we developed the GT1 car. The idea was to have it as close to the road car as possible, and so for the 1996 and 1997 seasons, we took the steel body shell of the 911 and cut it behind the driver seat. We then made up a frame which we attached to the back of this, and by turning the engine and gearbox around, we had a mid-engined car,” Norbert Singer revealed with a smile.

Porsche’s entry in the 1996 Le Mans race ended with a second and third place, just a lap down on the winner, but in their eyes, this was clearly not good enough. The 1997 model was a significant upgrade on the ’96 model, but the works car failed to finish which could have signalled the end for the car of Singer’s dreams. Fortunately, a batch of 21 GT1 road cars were produced featuring the new 1997 Evo upgrades, the sale of which to eager customers helped to fill the coffers. The following year, 1998, was Porsche’s 50th anniversary and the company needed to make a big splash, and so an altogether new GT1 was planned.

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Once again, as with the ‘96 and ‘97 cars, the brief was that the new GT1 should still resemble the production 911, and so under the watchful eye of Singer and Horst Reitter, a new mid-engine concept based around a carbon fibre monocoque began to take shape. The FIA regulations dictated that an all-new GT1 car could be built for competition as long as it was accompanied by a road legal version. Just a single road car was required, and this appealed to Norbert Singer as it meant he did not have to set up a production team to get a larger number of street cars assembled. This of course meant that the race car had not only to meet all the necessary safety criteria for both motorsport as well as road use, but above all, it also had to be instantly recognisable as a 911.

Tony Hatter, the British-born designer responsible for the ‘96 and ‘97 GT1s, was called upon to work with the motorsport department in creating the new car for 1998. Around 90 kg had to be shed from the earlier car which had proved too heavy with its 993-based steel shell, and improvements also had to be made to the car’s aerodynamics. The motorsport department prepared a package (basically a design brief) for the 1998 GT1, around which the design department had to create the bodywork including doors, glass, lights and everything that goes with building a new car. The differences between the GT1/96 and the GT1/98 were very stark. No longer was the GT1 a hybrid car in any sense of the word, the only production items on the ‘98 model were the front and rear lights, but more about that later.

Where did it all start?

“It always starts with the regulations, and the regulations allowed us to make a whole new car, which this is,” Porsche Chief Designer, Harm Lagaaij said. Where the 1996 car was clearly a hybrid with 993 parts, and to a slightly lesser extent the 1997 car too, the 1998 model was a clean sheet of paper design, a non-hybrid car with ‘absolutely no standard parts’ apart from the front and rear light units. “When that project started in 1997, they hired the experienced Dutch freelance racing car engineer, Wiet Huidekoper (having previously worked on Spice and Lola Cars), and he worked together with the engineers in the motorsport department. Obviously, Porsche don’t mention him that often, but he was extremely important for the development of the 1998 car,” Lagaaij added.

In contrast with the ‘96/97 models, which were designed one hundred per cent in the Porsche design studio, the 1998 GT1 was designed by the motorsport department in accordance with the regulations. Porsche Designer, Tony Hatter expands on this, “I was locked up in a small room in the wind tunnel with a CAS (Computer Aided Styling) modeller for weeks. We digitally created the bodywork over a package from the motorsport department. A body was then milled from the data in 1:3 scale for wind tunnel work. We worked together with Norbert Singer for a long time, continuously modifying the model, taking measurements and putting all this back into our digital model. This was a process that was still in its infancy then, but this is basically how we now work in styling.”

Body and aerodynamics

There was no regulation requiring Porsche to draw any likeness with its 911 range of cars, the only requirement was that one road legal model of the race car be made. As a result, the 996 headlamps and tail lights were included by Lagaaij and his team, in response to the Board’s insistence that it resemble the 911 for marketing purposes. This was actually no easy task as Lagaaij recalled with some humour, “We tried to work the headlamps from the 996 into the design which was, well let’s call it difficult. The angle of the front fenders is totally different [from the roadgoing 996], so you had to implant it into the shape of the front fender. The headlamp is the same, but of course the position of the headlamp internals is at a different angle.”

Starting at the front of the ‘98 GT1, Lagaaij pointed out, “This was a completely new front end, the suspension was different, the radiators, the chassis, the splitter and the spoiler, everything was different.” Whereas the ’96 and ’97 models had a single large centrally-mounted radiator, the 1998 GT1 had a totally different cooling system with two smaller radiators, one on the left and one on the right, with outlets just ahead of the front wheels.

In fact, it is fair to say that everything on the car was different, with the exception of the engine. The rear diffuser is much more efficient than on the ‘96 and ‘97 cars, being both longer and steeper, and as a result the dynamic figures are very different too. Viewed from the front, the greenhouse is much narrower which required a bespoke, wrap-around windscreen. Harm Lagaaij explains, “The dimensions of the ‘96/97 and the ‘98 models were completely different. The greenhouse was designed around what the regulations allowed us to do with the minimum frontal area. There were no parts [transferred] from the roadgoing cars like the windshield or side windows, but Tony did a really good job with the rear end to integrate the 996 tail lamps.”

Tony Hatter explains the origins of the ‘slatted’ panels behind the doors, “The ‘slatted’ part of the side window graphic was taken over from the GT1/96-97 cars. This design element was taken as a reference from the Le Mans class winning 356 SL in 1951.” Fresh air was supplied for the driver through a discreet, centrally-positioned air scoop just ahead of the windscreen. The slatted section just behind the doors, as described by Hatter, extracted air from the cockpit, creating an efficient airflow for a cooler cockpit.

Where the ‘96/97 model was based around the shell of the 993-production car, the 1998 GT1 was the first Porsche to receive a carbon fibre monocoque. Coupled with the narrower greenhouse, this resulted in a wider body section that ran between the front and rear wheel arches. This required very different treatment of the ‘door sections’ as Harm Lagaaij referred to it, as the production doors could no longer be adapted to fit the new body. “When they were opened, the doors moved forwards and upwards in the one movement. They were hinged on the A-pillar on the ‘98 car, whereas on the ‘96/97 car they were hinged as on the normal 911 [of the day],” Lagaaij pointed out.

The completely new monocoque/chassis allowed the Porsche engineers to examine all areas of the car, looking for areas where improvements could be made. As a result, the wheelbase of the ’98 model was extended from 2500 mm to 2690 mm, which saw the car’s overall length increase from 4710 mm to 4925 mm.

Given that the ‘98 GT1 was no longer based around a production shell, the new car with its monocoque chassis had to undergo its own crash test. With the ‘98 GT1’s clean sheet of paper design, the car’s weight distribution could now be optimised with freedom. This allowed the designers to relocate the 100-litre fuel cell to a central position between the cockpit and the engine compartment bulkhead. Contrary to expectations, the carbon fibre body panels for the ‘98 model were made by CTS in England. This company was originally the composite shop belonging to Lola, but for commercial reasons it was formed into a separate company around this time in order to attract new business, which it did, even from its rivals.

Immediately evident at first glance, are the two very large exterior mirrors. These were once again based on the regulations at the time, which for the GT class, were required to provide a rear view of a certain area down the side and the rear of the car. As a result, there was very little the design team could do about this other than to make the mirror housing as streamlined and as light as possible. This requirement only applied to the GT class of cars for the three-year period in which they were eligible to race, between 1996-1998. Lagaaij confirms this, “The moment you have the regulations saying that you have to have a streetcar, you have to go through the various roadgoing legal requirements, and one of them was the mirrors. The mirrors have to fulfil the same requirement as any roadgoing car, small or big, and therefore in this case they are huge.”

Looking at the rear section of the car from the side, the profile around the rear lights would appear to resemble a ‘V’ lying on its side. The upper arm of the ‘V’ rises up to form the strong rear deck which provides downforce at speed. Running across the full width of the rear deck on its trailing edge is a lip, which acts as a Gurney flap. The lower arm of the horizontal ‘V’ extends down to form the outer edge of the diffuser. The shape of this ‘V’ served more than this purpose though, as Harm Lagaaij explained, “The shape of it was necessary to make it road legal otherwise you couldn’t see [from the side] whether the lights were on or off, or if the indicator was blinking.”

Engine

The engine fitted to the GT1 (Type M96/80) was based on the same, traditional 6-cylinder boxer motor architecture as in the earlier model, but the capacity was very slightly increased from 3164 cc to 3198 cc. This was achieved by increasing the bore from 95 mm to 95.5 mm while retaining the same 74.4 mm stroke. The engine consisted of an aluminium block or crankcase and aluminium heads, and was water-cooled throughout.

Breathing through a pair of 33.9 mm air restrictors, the engine was quoted as developing around 550 bhp at 7200 rpm, but the actual output was thought by most to be much higher. Turbocharging was by two KKK K27.2 exhaust turbochargers with twin intercoolers. The electronic engine management system was provided by a TAG 3.8 system.

The GT1’s gearbox was a 6-speed manual unit (Type G96/80) with a sequential shift mechanism. The change sequence was backwards for upshifts and forward for downshifts. Additional gearbox lubrication was by means of a separate oil pump with an oil-to-water heat exchanger. A triple disc carbon fibre clutch was fitted.

Harm Lagaaij recalls the silencer requirements, “For the street version of the 1998 car, the roadgoing exhaust system was necessary to make it road legal. This was a masterpiece!”

Wheels, suspension and brakes

An advantage of building a completely new car was that it allowed the engineers to modify the front suspension. No longer did the suspension have to conform to the limitations of a production body shell, and so double wishbones with pushrods and adjustable Bilstein shock absorbers were fitted front and back. Carbon disc brakes were used on all four wheels, 380 x 37mm, with 8-piston (front) 6-piston (rear) callipers.

When looking at a race car, like a Formula 1 or an LMP1 race car, it is clear that they are not fitted with low-profile tyres. A high-performance street car might have extremely low profile tyres, but on a racing car the tyres have higher walls. Tony Hatter confirms this, “The GT1 was designed to be a race car and has wheel arches big enough to accommodate bigger tyres. The GT1/98 street car was fitted with the best high performance tyres they could get, but the tyres are lost in the wheel arches. The wheel arches look much too big on the road car but only because the tyres are smaller (low profile) than on a race car.

Interior

Because the 1996 car was based on the 993 model, its interior was production-based, but in the 1998 GT1 the interior was completely race-orientated. Facing the driver in both the ’98 race car and the road car, is a single digital display panel which provides all the information necessary. The only other instruments in the road car include a small number of warning lights on the dashboard for the battery, handbrake, indicator lights, and switches for the lights, fan and hazard warning.

The GT1 road car is a right-hand drive vehicle, which suited the predominantly clockwise racing circuits around the world, and so the gear shift is located on the driver’s right side. The steering wheel is simple and typical of a race-bred road car, having a flat bottom with two curved sections rising up, but it is not joined at the top so that the driver can read the instrument panel. The indicator stalk almost looks out of place in the austere surroundings, as apart from two racing seats, the interior is devoid of any other road car comforts.

The roll out

Bob Wollek was the driver entrusted with the GT1/98 roll out. Tony Hatter recalls the roll out, “I can remember, it was getting dark and it was very cold, it always seemed to be cold and miserable here when these things happened. We were at the entrance to the test track and the car was sent off into the dusk. They had set up floodlights and when the car came back, it stopped and I saw a haze coming off the car and the parts were creaking.”

When it returned, the mechanics opened the door and chatted briefly with the driver, and then they closed the door and sent him off again. Hatter described the scene as like watching a Steven Spielberg science-fiction film, with the headlights shining through the mist, the steam coming off the bodywork, it was just surreal.

“The next time he came past, he was at full power down the straight, it was absolutely unbelievable! This thing worked straight out of the box,” he added.

Harm Lagaaij put it this way, “It drove so nicely, it was intoxicating to drive that car. It was 1998 state-of-the-art racing technology and of course, the faster you went, the more downforce you had, which is the intoxicating part because the more courage you had to take corners at higher speeds, the reward was that you got more downforce. This is why I liked them so much.”

It would be fair to say that the difference between the ‘96/97 car and the 1998 car, was like a generational change. The first two cars were much closer to each other in terms of technology, compared to the ‘98 car. “Its seating position, pedals, steering wheel, gear change, monocoque, front suspension, cooling and the aerodynamics, were worlds apart,” Lagaaij added.

Conclusion

There was only one street version of the GT1/98 built, and that was retained by the factory as the homologation model for the race car. Despite being a roadgoing model, it was built by the same engineers who built the race car and who were located in Flacht, the village neighbouring Weissach. With the Weissach facility having grown over the years, the R&D part of this department lay in Weissach while the motorsport team who were all under the same roof, were geographically within the village boundary of Flacht. Just so that the wider world knew where this car was made, a sticker with the words ‘Made in Flacht’ was applied below the left rear lamp unit. This had been a tradition within the Motorsport department for some time. Simply put, this was, and still is, the most extreme 911 ever built!

Technical specifications – chassis #WP0ZZZ9RZXS100001:

Written by: Glen Smale
Images by: Virtual Motorpix/Glen Smale & Porsche