Group 5 rules offered manufacturers a great deal of freedom to modify their cars in the Silhouette class. At Porsche, Norbert Singer pushed the rules to the limit, and gave us the Porsche 935/78 Moby Dick, truly a legend in its own time.
In the 1970s, Porsche had several things going for it on the motorsport stage. Firstly, they had built up a wealth of experience with turbocharging; and secondly, they had in Ernst Fuhrmann a CEO who believed in the benefits of motorsport. And then they had Norbert Singer, a motorsport engineer who had originally wanted to be an aeronautical engineer, but when a position at Porsche presented itself in March 1970, he took that instead.
With an interest in aerospace, a knowledge of aerodynamics and weight conservation also came in handy when applying this to racing cars. His first task at Porsche as a young engineer involved cooling on the mighty 917s, but in just a few short years he was already making his presence felt in Porsche’s race department.
At the start of the 1976 season, the Group 5 regulations referred to a ‘silhouette’ car, but any definition of what a ‘silhouette’ comprised, was not spelled out in the regulations. This term was deliberately loose in its meaning, so that the manufacturers competing in Group 5, could develop race cars that looked like a production car, but were clearly powerful, all-out racing machines. Porsche’s contender for Group 5 was the 935, but the model had to go through two evolutions of development before the third iteration, the mighty 935/78 or ‘Moby Dick’ was born.
It would be useful to also explain the characteristics of some of Porsche’s rivals in this class. The Group 5 class covered the Porsche 935, BMW 320 Turbo, 3.0 CSL and M1, Zakspeed Ford Capri and Escort, Lancia Stratos and Beta, Nissan, Toyota and others. This fourth generation of the Group 5 class, catered for ‘Special Production Cars’ between the years 1976 to 1982.
The idea was to allow cars to race in this class that shared a similar silhouette to the production car they were modelled on, but did not trace exactly the outline of the roadgoing model. The FIA wanted to distance itself from the large, ugly fender extensions that looked like they had just been stuck on to satisfy a certain rule. They wanted, instead, to have race cars that bore some similarity to their roadgoing siblings, but where wider fenders, wings and splitters looked like they had been moulded into the overall shape of the car. Whether or not the cars followed the spirit of the rule, is open to interpretation and personal opinion.
It could be said that the Porsche 911 started out with several advantages over its rivals in this class. For starters, the 911 had wider front fenders, it had no need for a water radiator to cool the engine, and the engine was located at the rear of the car. The Ford Capri, BMW 320 Turbo and all the other cars, were conventional front-engined models which meant that the exhaust pipe had to run the length of the car, or possibly exit at the side. They were all water-cooled and therefore needed a radiator up front, and they all had their lights in the front grille, which meant that their front fenders were narrow in comparison with the Porsche. Why were these factors important, well each of these will be expanded upon below.
When the first version of the 935 appeared in 1976, it featured a flatter rear wing and headlights in their conventional position in the fenders, but the 1977 version already showed signs of where the ultimate 935 was heading. The headlights had been removed from the conventionally-shaped fenders, which were now downward sloping and more streamlined. Norbert Singer was the project engineer on the 935, “A favourite thing for me was the regulation on the fenders. With wider tyres, we needed an extra 50mm but the FIA wanted to avoid these ugly wheel arch extensions, so they said the shape of the fenders would be free. So luckily, or unfortunately, it depends who you were working for, the fender of the 911 was very wide because you had the headlights in the fenders. BMW and Ford had their headlights in the grille, and so the fenders on those cars were narrower. With the fenders being free you could modify the 911 completely, so we took the headlights and put them down in the bumper making it look completely different.”
This move allowed Singer to lower the front fenders to line up with the slope of the bonnet which was of course its permanent shape, giving the race car an immediate aerodynamic advantage. The other front-engined cars could not do this because the engine was in the way, and altering the shape of the fenders would not have given them any advantage.
The regulations required the manufacturer to keep the windows of the production car, as Norbert Singer explained with a smile, “We made a new rear window, a kind of double window. We left the old production window inside but we put another window on top so you could easily see the production window from the outside, but the airflow was much better.” The 935/78 was fitted with a long tail which maximised the air flowing off the modified rear bodywork, making the car almost as fast as the prototypes at Le Mans.
If Singer’s interpretation of the rules relating to the double rear window and the front fenders was ingenious, the lowering of the whole car by eight centimetres was the icing on the cake. Ford and BMW also raced in the World Championship but they were handicapped because of their front engines, as the regulations required the exhaust pipes to exit behind the centre of the wheelbase. Because of its rear engine, Porsche didn’t have this problem, as the exhausts exited at the rear of the car and did not have to pass under the floor of the car. The other manufacturers wanted to change this regulation, allowing them to modify the door sill, and thereby lowering the ride height of the car. In a meeting with the FIA, it was agreed by all the competitors that the sill could be modified to allow the car to be lowered and for the exhaust to exit in the same place. Fortunately for Singer, the new regulation allowing this modification was written in general terms. “After we left the meeting I had the idea that by being allowed to modify the sill, we could cut it along its full length. This was the eight centimetres that we cut out,” Singer explained with a satisfied smile.
As the front and rear fenders had been widened significantly, it seemed perfectly logical to complete this extension over the door too, to avoid creating excessive air turbulence along the side of the car. Because this was, in Singer’s words, on the ‘edge of the regulations’, he invited members of the FIA’s Technical Subcommittee to inspect the car at Weissach. Well-known journalist and racing driver Paul Frere, and Curt Schild, a Swiss engineer, arrived to inspect the car.
“They were actually close to having a heart attack,” recalled Singer. “’What are you doing?’ they exclaimed, but we explained our ideas in terms of the regulations. In the end, they agreed that it conformed to the regulations, and they submitted their report to the Technical Commission. But the Technical Commission said, ‘No way!’”
The problem was that Porsche only received the Commission’s decision about three weeks before the first race at Silverstone. With the first race looming, something had to be done, as Norbert Singer explains, “I went back to the wind tunnel to see how we could work out a compromise, and it turned out that the first section along the door was the most important part.” With this finding, Singer and his team fabricated a partial door cover, extending rearwards approximately 12-14 inches in length from the door’s leading edge.
“This was aerodynamically nearly as good as the complete cover with the NACA duct. So, in the end we had a solution which was, let’s say 95 per cent as good as the original one, and although it didn’t look as good, on the technical side it gave almost the same efficiency,” he added.
However, this was not the end of the story, as with just a week to go, Singer received a telefax from the president of the FIA in which he stated that the initial decision of the two visiting delegates (Paul Frere and Curt Schild) was the one that should stand. In short, the president of the FIA overturned the decision of the Technical Commission, giving his permission for Moby Dick to run with its first set of doors. “But it was too late because we were ready to leave for the first race at Silverstone, and we had to board the ferryboat. So that is why we raced like this,” Singer concluded.
Engine and drivetrain
Development of the engine saw the introduction of a first for the company, water-cooling in a 911 engine! The regulations required a production engine block to be used where some machining was permitted, but the heads could be modified. This worked perfectly for Porsche as this allowed them to retain traditional air cooling for the cylinders, but importantly, water-cooling for the heads allowed the introduction of 4-valves per cylinder. This meant that the fan, which had to be retained by regulation, could now be smaller as it only had to cool the cylinders.
Each bank of cylinders had its own water pump which was gear-driven, the water-cooling thus lowering the temperature of the heads significantly and thereby increasing the operational efficiency. With the increased pressures achieved in a turbocharged engine, welding the heads to the cylinders of the 935/78 was of great benefit, while at the same time doing away with the need for a gasket.
Power increases also came from a more compact and efficient combustion chamber, a higher compression ratio, as well as the 4-valve heads (for the first time in a Porsche) which were operated by twin overhead cams. The operational rev limit was still 8000rpm, as on the previous 2.8-litre engine, but the additional power generated by the 3.2-litre engine was achieved largely through higher turbo boost. Turbo power was supplied through twin KKK turbochargers, coupled with Porsche-designed waste gates, with cockpit-adjustable boost pressure for the driver. With a boost pressure of 21psi, 750bhp at 8200rpm was achieved, but with the boost turned up to 25psi, as much as 845bhp was possible.
The gearbox on Moby Dick was inverted due to the car’s lower ride, and this was done to avoid the half shaft being at too extreme an angle for racing. The 4-speed gearbox was otherwise the same as that used on the earlier 934 and 935 models, with drive to the rear wheels being solid, dispensing with the need for a differential. The gearbox oil cooler was located in the right rear fender.
With the engine heads being water-cooled, this obviously required the installation of a water radiator. The dry sump also required an oil cooler, but there were insufficient holes through which to collect air separately for the engine, oil cooler, gearbox oil cooler and the intercooler.
On a practical level, all the openings through which they could collect air, were occupied. The problem was solved in a manner of speaking, insofar as the engine and oil cooling was concerned, by installing the two radiators low down in the nose, one behind the other. Singer explains the limitations of this setup, “When you put two radiators one behind the other, neither of the radiators is really working at its optimum because of the airflow.” This is because the rear radiator is receiving warmer air from the front one, and the pressure distribution from the front to the rear of the first radiator is different. “So, the first radiator is handicapped and the second is even more handicapped, that is why they are both so big,” he added with a smile. The air that exited these two radiators was directed under the car, and it would flow out rearwards without causing any noticeable underbody lift.
Most of the circuits that Porsche raced at in Europe ran in a clockwise direction, and as such most corners were right-handers. “In the past, because you had more corners to the right, they placed the driver on the inside to keep the weight distribution favouring the right, or the inside. So, we decided the next step to improve the 935 would be to put the driver on the right,” Singer pointed out. The only potential problem was changing gears, because on race cars like the 917, the gear stick was on the right-hand side, but in this case, it was not possible to move the shifter to the right-hand side.
Singer again, “We could have moved it, because this was free to move, but we had a short discussion in-house because we thought that the drivers might mis-shift and over rev the engine. I called Jochen Mass and Jacky Ickx as they were the drivers, and I asked them what they thought. They said, ‘No problem, we sometimes race in England with road cars, we will get used to it after a few laps.’”
During the building process of Moby Dick, the car was on stands in the workshop at Weissach without wheels. This height made it easier to work on and for the mechanics to work under the car as required. Once the car was completed and ready for its first test run, the car was painted completely in white.
Norbert Singer recalls with some humour, the moment Moby Dick was rolled out, “You can imagine, after seeing the car for weeks at a certain level, you get used to it. Then you fit the wheels and bring it down to the floor, and this combination of being 8 cm lower the increased width and the car was much longer, it was quite a shock. And I think one of the mechanics said ‘It looks like Moby Dick’, and that just stuck.”
Martini colour scheme
The Martini colour scheme on Moby Dick, was one of the most striking designs in the paddock, and so typical of the day. The 1970s is well-known as one of the most colourful decades in recent history, and loud, in-your-face colour schemes had become the norm in racing circles. Moby Dick did not escape the artist’s attention, and as Norbert Singer explains, it was Porsche’s own styling department who were responsible for this. “It was mainly Porsche, of course they made some proposals and they sent to Martini, it was Count Rossi in these days, and he agreed and he just said, ‘why not’. Count Rossi liked these stripes, this was his favourite.”
On 14 May 1978, Moby Dick stepped up to the plate for the Silverstone 6 Hours and delivered its first, and only, race victory. Jacky Ickx qualified the 935/78 in pole position, beating the second-placed car, another Porsche 935, by two seconds. The race started in wet conditions and Jochen Mass made good his escape, and before long he was so far ahead of the rest of the field that the following horde was unaffected by his spray. The Ickx/Mass car was never troubled, and romped home seven laps clear of the second-placed car.
The 24 Hours of Le Mans, just a month later, was rather a different story though. Norbert Singer explains, “With the long tail it was a little bit of a Le Mans version. We wanted to have a higher top speed with this car, we got 366km/h, which was a lot at Le Mans, so this was the main goal.”
Qualifying started well enough with the #43 car placed third on the grid, three seconds behind the Porsche 936 prototype on pole. Moby Dick, though, was beset with niggling problems through the race, none of which were big in themselves, but the car was just unable to realise its full potential. “Unfortunately, the engine had a very high fuel consumption and we had 32 regular pit stops, but we were fast. Then, we had trouble with a small oil leak and this required two extra pit stops to fix. We also had a puncture, so I think we had about 36 pit stops in total. But with the performance, the car’s top speed and the lap time that we did in practice, I was quite happy,” Norbert Singer admitted.
Moby Dick contested two other races in 1978, bring its career total to four outings. After Le Mans, Jacky Ickx and Manfred Schurti gave Moby Dick its penultimate run in the Vallelunga 6 Hours, on 3 September 1978. Ickx set both the fastest qualifying time and the fastest race lap, but despite holding a comfortable lead, the works Martini-sponsored 935/78 snapped a fuel injection belt in the last 15 minutes of the race. Ickx was forced to coast into the pits and sit out the final eight laps in his garage. The car was classified as NRF.
For its final outing, Moby Dick was entered in the ADAC Norisring Trophy ‘200 Meilen von Nürnberg’ on 17 September. In front of a crowd of 90,000 spectators, and in the hands of Jacky Ickx, the works Porsche failed to finish after it had completed just 14 laps. The problem this time was brakes, which up until that point had not been one of the car’s failings.
Without doubt, when talk in motorsport circles turns to Moby Dick, the stories and memories stirred by this legendary racer ensures discussion well into the small hours. Most Porschephiles will have no trouble identifying Moby Dick when it appears on demonstration runs. While the car in period achieved less than might have been expected, Moby Dick represents a time when relative freedom and liberal interpretation of the rules allowed such cars to be built. Singer’s interpretation of the rules was bordering on the outrageous, almost rebellious, but the silhouette era saw some of the most colourful and competitive racing in recent history. We are all the richer for such wild thinking, the likes of which we are unlikely to see again.
1979 Moby Dick development
With the Porsche 935/78 Moby Dick racer being active in 1978, this was just a few years short of the introduction of the Group C class in 1982. Already at this time, ground effects was being talked about and within four years, the Porsche 956 was launched which featured a full ground effects package. Norbert Singer elaborates, “Ground effects was a fantastic idea, but I never really looked underneath the car because it had to be flat. So, I came up with an idea and I said for the next Moby Dick, in 1979 or 1980, how could we introduce ground effects on that car? But remember, ground effects meant you needed a big diffuser.”
A bigger rear diffuser was not possible because the engine was in the way, but where there a will there is a way. Singer again, “I had a small budget to make a wind tunnel model and to try to experiment with ground effects using that Moby Dick based car. The engine was a problem because it is heavy and it was mounted as low as possible, which is exactly where you want to put the diffuser. So, I had the idea to start the diffuser behind the seat of the driver and exit underneath the rear window.”
The diffuser would have exited just below the rear window, basically making the whole rear interior of the car into a diffuser. “The whole rear section, which is the luggage area or the rear seats, was completely removed and it just contained the diffuser. The wind tunnel model showed that it was promising, but that was the end of it, and the project was stopped,” Singer concluded with a satisfying laugh. When Norbert Singer makes such a claim, then you have no option but to believe him.
Considering what a ground effects 911 would look like, and what could have been achieved by a Moby Dick developed along these lines in 1979 or 1980, is a tantalising thought.
|Engine type||935/71: 6-cylinder, horizontally opposed|
|Bore x stroke||95.7 x 74.4mm|
|Fuel delivery||mechanical Bosch/Kugelfischer fuel injection|
|Power output||750bhp @ 8200rpm (max: 850bhp @ 8200rpm)|
|Maximum torque||785 Nm @ 6600rpm|
|Transmission||4-speed manual (Type 930/60)|
|Suspension||front – wishbones with McPherson struts; rear – aluminium semi-trailing arms; progressive rate coil springs; Bilstein gas-filled telescopic dampers|
|Wheels||front – 16” dia. x 11” width light alloy with centre-lock nut; rear – 19” dia. x 15” width light alloy with centre-lock nut|
|Tyres||front – Dunlop racing 275/600 x 16; rear – Dunlop racing 350/700 x 19|
|Body||unitary steel construction stiffened with aluminium tubing; front and rear hoods, doors and fenders in plastic|
|Top speed||more than 220mph (350km/h)|
Written by: Glen Smale
Images by: Virtual Motorpix/Glen Smale & Porsche Werkfoto