The 1978 24 Hours of Le Mans was the 46th Grand Prix of Endurance, and took place on 10 and 11 June 1978. In many ways it was a continuation of the race from the year before – the two main protagonists would be the very evenly-matched works teams of Alpine-Renault and Porsche, with four cars each. The race was not valid (did not count points) for any championship.
This time it was the Porsche team that had reliability issues – on only the second lap of the race two of their cars were in the pits. Renault soon established a solid hold of the top three positions. Like the year before, after the Ickx /Pescarolo car had early problems, Ickx was transferred to the second Porsche of Barth/Wollek. Once again he set about driving back through the field during the night, getting up to second by midnight behind the Jabouille/Depailler car. But a loss of fifth gear cost them half an hour to repair it. When the lead Renault Alpine A443 stopped on the circuit with a jammed gearbox, there was a sense of déjà vu for the French team. The sister Renault Alpine A442B of Jean-Pierre Jaussaud and Didier Pironi inherited the lead, with a 7-lap margin over the Porsches. Although the second-placed Porsche pulled back two of those laps, this time Renault would not be denied, and Pironi took the flag for a popular local victory with a record race-distance.
Porsche were second and third, the remaining running Renault fourth with the Porsche 935s of customer teams in the next four places. The race also saw several high-speed crashes on the Mulsanne straight, but only one driver was seriously injured.
Regulations With the predictable demise of the FIA Championship for Group 6 (World Championship for Sports Cars), Le Mans was left as the only significant race that combined Group 6 and Group 5 racecars. No changes were made to the race regulations.
This year, the IMSA GT Championship added the Le Mans GTX class to the incumbent GTO and GTU classes. Wimpffen 2007, p.268 This, in turn, meant the Automobile Club de l'Ouest (ACO) could merge the IMSA and GTX into a single class. The IMSA regulations allowed a lower minimum weight and wider rear wheels than Group 5. IMSA also inaugurated the World Challenge for Endurance Drivers. Not sanctioned by the FIA, it was a series that linked American races at Daytona, Sebring and Talladega with Le Mans and the Nürburgring. Finally, the Daytona-Le Mans Trophy was repeated. Wimpffen 2007, p.264-5
Entries The ACO received only 70 applications, the smallest number in a decade with 60 chosen for qualification with a further 7 kept on reserve. Once again, the only manufacturer works teams were from Porsche and Renault, bolstered by entries from small-scale racing specialists Mirage, Osella and WM.
Class Large-engines >2.0L classes Medium-engines < 2.0L classes Turbo engines Group 6 S Sports 14 / 12 15 / 14 9 / 0 Group 5 SP Special Production 9 / 8 - 8 Group 4 GTS Special GT 10 / 7 - 6 GTP Le MansGT Prototype 6 / 5 - 2 IMSA GTX IMSA/Le MansGT Experimental 13 / 9 - 2 Total Entries 52 / 41 15 / 14 27 Note: The first number is the number of arrivals, the second the number who started.
Group 6 and GTP
Defending winners, the Martini-Porsche works team, brought back the 936 for its only race of the season. The 2140cc engine with twin KKK (Kühnle, Kopp & Kausch) turbos had been enhanced with quads-cams and at 1.4bar of turbo boost now put out 580 bhp. Wound up to 1.7bar, it was a bit slower at top speed 345 kp/h (215 mph) but overall, with new aerodynamics, much faster around a complete lap. The extra engine power meant higher running temperatures and for the first time, Porsche had water-cooling, combined with its regular air-cooling.Armstrong 1978, p.156Spurring 2011, p.280-1Clarke 1997, p.65-6 Autosport Jun8 1978Clarke 1997, p.67 Autocar Jun10 1978 The cars were also fitted with the same gearboxes the Can-Am Porsche 917s had used to handle the great engine power.Armstrong 1978, p.161 Once again, the endurance experts Jacky Ickx and Henri Pescarolo were paired up, and given the new car. Jürgen Barth had a new co-driver in Bob Wollek, driving the car that failed to finish last year fitted with the new engine. For Wollek, it was his first drive with the works team, after fulfilling a prior commitment with Kremer the year before. Americans Hurley Haywood and Peter Gregg were given the winning car from 1976 and '77, still fitted with the twin-cam, single-turbo engine. Jochen Mass and Reinhold Joest were designated as reserve drivers.Spurring 2011, p.280-1
After a disastrous showing the previous year, Renault Alpine did extensive work on the 2.0-litre twin-turbo engines, making over thirty modifications. The chassis also got scrutiny, with side-skirts and a Perspex bubble-canopy trialled. They did unprecedented testing, covering over 10,000 miles (16,000 km) at Circuit Paul Ricard and Istres airfield. Two short-tail chassis from the last season were given the new engine (A442A), while another was given a longer chassis (A442B). Finally, a brand-new chassis (only unveiled a month before) was built (A443) that had a 15cm longer wheelbase and was broader to carry wider wheels.The bigger 2138cc engine with a single turbo put out slightly more power (520 vs 500 bhp) but could reach 360 kp/h (225 mph) on the Hunaudières straight, fully 25 kp/h faster than the Porsche.Spurring 2011, p.276Clarke 1997, p.68 Autosport Jun8 1978 Once again, the cream of French Grand Prix talent was brought in: Jean-Pierre Jabouille/Patrick Depailler shared the new car, Jean-Pierre Jaussaud/Didier Pironi had the A442B. The older cars were driven by rally specialists Jean Ragnotti, Guy Fréquelin with José Dolhem and Jean-Pierre Jarier with Le Mans veteran Derek Bell.Spurring 2011, p.276 Patrick Tambay had been slated to race with Jabouille, but his burned foot had not healed sufficiently.Clarke 1997, p.72-3 Motor Jun17 1978
Mirage engineer John Horsman further developed the M8 to the M9. Keeping the 490 bhp Renault turbo engine, the new chassis was lower and narrower, with a long tail.Spurring 2011, p.287 The revised gearing was able to be tested on the new Interstate 10 section outside of Phoenix before it opened, where team driver Vern Schuppan was able get the car up to 335 kp/h. Two cars were entered: Schuppan had Formula 1 driver Jacques Laffite as co-driver, while Sam Posey and Michel Leclère once again shared the second car.
Alain de Cadenet brought his next iteration based on the Lola T380, designed by Len Bailey (who had previously worked with John Wyer). The LM78 was longer, and faster: with the 460 bhp Cosworth DFV engine, De Cadenet's regular co-driver Chris Craft was able to make 345 kp/h (215 mph) on the back straight. A true privateer effort, as de Cadenet got virtually had no sponsorship.Spurring 2011, p.288 He even sold most of his valuable stamp collection to raise money. Last year's model had been sold to privateer Pete Lovett, while the earlier model returned with Simon Phillips. A new entrant this year was the Ibec, for the Ian Bracey Engineering Company. The Ibec P6 was designed by Harvey Postlethwaite, currently involved with the Hesketh Formula 1 team and the chassis layout was based on the Hesketh 308. But the focus on that meant the Group 6 car fell behind schedule so Bracey took the car to the Lyncar plant to assemble. Drivers Ian Grob and Guy Edwards got their first drive of the car in testing less than a fortnight before the race.Spurring 2011, p.289
After the withdrawal of the sponsorship money of Inaltéra, Le Mans local Jean Rondeau, despite keeping the design plans, had been forced to sell his cars and start building his designs again. He toyed with a 6-wheeler idea inspired by the Tyrrell P34. Assisted with funding from the city and local region his new car, the M378, was narrower, longer and lighter than the previous model. Testing on the Bugatti Circuit improved the aerodynamics.Spurring 2011, p.286 His co-drivers were rally driver Bernard Darniche and Jacky Haran. One of the Inaltéra bought by the Swiss concern was entered in GTP by André Chevalley. Welter Racing had a new design in the GTP class. The P78 had a longer, more aerodynamic shell. It kept the Peugeot 2.7-litre V6 engine with a KKK turbo and, after improvements, now put out 440 bhp. It would be driven by Debias/Sourd/Mathiot. The team also had last year's P77 model with its same turbo engine (Raulet/Mamers and the older P76. Driven by Bob Neyrat's squad of female racers Christine Dacremont/Marianne Hoepfner, it had a bigger 2.85-litre Peugeot non-turbo engine.Spurring 2011, p.291 The other GTP entry was the return of Bernard Decure's modified Alpine A310.Spurring 2011, p.262
Group 6 (2-litre)
This year, the biggest class was the 2-litre category with fifteen entries. The class showed a good variety of chassis combined by different engines. The French engine-builder team, Société ROC, had three of the B36 Chevrons. This was the last model of Chevron produced when company founder Derek Bennett was killed in a hang-gliding accident.Spurring 2011, p.292 The Simca-ROC engine was also seen in two Lola. Two types of Cosworth engine powered the other five Lolas, as well as Charles Graemiger's Cheetah. With the demise of the World Group 6 Championship, the European Sportscar Championship was revived and Osella supplied a number of customer cars. Ted Toleman brought one of the Osella-BMWs to Le Mans, co-entered by BMW's British division, with a strong driver lineup of Tom Walkinshaw, Dieter Quester and his Formula 2 team driver Rad Dougall.Spurring 2011, p.296 Once again the small Sauber team was back with the C5, powered by a BMW engine. This year Swiss Formula 2 driver Marc Surer joined the regular drivers Eugen Strähl and Harry Blumer.Spurring 2011, p.293
Group 5 and IMSA GTX With the Porsche works team not contesting the World Championship, it devolved to a duel between the two German customer teams of Georg Loos (buying the services of the underemployed works pit-crews) and Kremer Racing with their 935s. BMW, with their new M1 model delayed, had to make do with the 2-litre 320i in the junior Division 1 class, that could not compete with the bigger cars. Porsche produced fifteen 935 cars for their customer teams. The 1978 version had twin-turbos and a two-level rear wing to improve downforce. Armstrong 1978, p.164
Meanwhile, the Martini-Porsche works team had developed their Third Generation of the Porsche 935. Nicknamed "Moby Dick", the mighty 935-78 had the most powerful Porsche engine since the 917 Can-Am turbos of the early '70s. The 3.2-litre flat six twin-cam could put out a massive 750 bhp with its twin KKK turbos. Engineer Norbert Singer had ingeniously lowered the car, by lifting the chassis floor, fitting the gearbox and final-drive upside-down and putting the radiators in front of the massive 19" rear wheels. The engine-size bumped it up to the 5-litre class, it had to have a minimum weight of 1025kg (compared to ~800kg for Group 6) and the smaller 120-litre petrol tank for Group 5 cars would demand more fuel-stops in the race (45-minute stints vs 80-minutes for Group 6). Ickx and Mass had won on its only race to date, at Silverstone the month before. As in previous Le Mans, the Group 5 car was handed to Rolf Stommelen and Manfred Schurti.Spurring 2011, p.282
There were seven other 935s entered by the customer teams. The Kremer brothers had three cars, despite losing their two main drivers (Wollek and Pescarolo) to the works team. Instead they had three relatively inexperienced sets: Gurdjian/Dieter Schornstein/Louis Krages, Raymond/Franey/Wielemans and Americans Busby/Cord/Knoop.