Tuesday, July 3, 2001

936 Race Car

Excellence, Flat 6, 911 & Porsche World

The 936, one of Porsche's most successful racing cars, was developed because Porsche felt that they were forced to build a car that they had not intended to build. In 1976 there was a new form of rules that governed Sports and GT racing. Initially there were only supposed to be classes for production based cars in Groups 1 through 5. The World Manufactures Championship would be determined by the "Silhouette" formula for Group 5 cars and Group 5 is where Porsche intended to race with their 911-based 935. Porsche had done all of their development work in 1974 with the with the Carrera RSR turbo in preparation of running Group 5 cars in the new World Manufacturers Championship. These new rules were supposed to take effect in 1975, but they were delayed a year until 1976. In 1975, almost as an after thought, the FIA decided to add an additional World Sports Car Championship class to the series as the Group 6 type sports cars, so instead of one World Championship there now there would be two World Championships. 



The Automobile Club de L'Ouest, who puts on the Le Mans 24 hour race each year also preferred the open prototype cars from the earlier prototype racing formula and opened their Le Mans race to both group 5 and group 6 cars. Porsche feared that FIA would also run races that would allow both Group 5 Silhouette cars and Group 6 sports prototypes to race against each other in the same race. They knew that if this happened that the sports prototypes would dominate the overall standings and obscure whatever success the silhouette cars had. Porsche was not willing to compete in the Group 5 World Manufactures Championship, a championship that they felt confident about winning only to be beaten for the overall victory in the races by the Group 6 sports prototypes, so to be sure that this would not happen Porsche decided to build their own Group 6 sport prototype the 936. Fortunately FIA never race d the two championship classes together so the only place that Porsche's group 5 935 had to compete against the faster group 6 sports cars was at Le Mans. 


Under the new FIA rules the classes which pertained to Porsche were Groups 3, 4, 5 and 6. Group 3 was for GT cars with a minimum production of 1000 cars per year. Group 4 was for GT cars with a minimum of 400 cars in two years, and group 5 was a very liberal "silhouette formula based on cars which were homologated in Groups 1 through 4. These Group 5 cars competed for the World Championship of Makes. The Group 6 class and the Sports Car World Championship was created ostensibly to give cars from the previous 3.0-liter sports prototype class a place to compete. 

When the FIA created this new championship for the Group 6 cars it appeared that the Alpine-Renault and Alfa-Romeo teams would be the only competitors in this class and that the Alpine-Renault would probably run at Le Mans uncontested, Porsche rose to the occasion, producing yet another new car, the 936 to compete in this Group 6 class. The 936 would prove to be a very successful effort, winning the Group 6 World Sports Car Championship, Le Mans and giving Porsche a double World Championship for 1976. The 936 prototype was a blend of the 908/3 and the 917 sports cars which used the engine from the 1974 Carrera RSR Turbo. The engine from the Carrera RSR Turbo was used because, like the 3.0-liter prototype class where the 1974 Carrera RSR Turbo had raced, the Group 6 cars had an engine size limitation of three liters, and for the turbocharged engines, there was also a 1.4 multiplier which limited the engine size to 2142 cc in displacement. 

The decision to build a group 6 car was a last minute decision made by Ernst Fuhrmann, Porsche's managing director in September 1975. It has been said that only a dozen people, the people actually building the cars, knew of the 936 project. One reason why Ernst Fuhrmann had decide to go ahead with the 936 is that because it used so many components from other sports racing cars that Porsche had already built it could be developed quickly and it would be relatively in expensive to develop and produce. The 936 engine was borrowed from the 1974 Carrera RSR Turbo, most of the running gear parts could be borrowed from the 917/10 or 917/30. The transmission was a Type 920 five-speed from the 1970/71 917 endurance racers. All that remained to be done was to design and build an aluminum tube frame chassis, suspension components and to design and build a body of fiberglass which would conform with the new Group 6 regulations. The go ahead for the project was given late in September of 1975 and the first car was built and testing at the Paul Richard circuit in February 1976. The test car was painted black in the hopes that nobody would notice it and taken along to test a test session for the group 5 935 at the Paul Richard in France. 936 001 was used in the wind tunnel at Volkswagen to develop the body shape to influence the lift and drag characteristics. 936 001 was also used for most of the development work for the 936s, a second car 936 002 ran most of the races in the Sports car World Championship series except the first race of the year Nürburgring and Dijon where 936 001 was used. From the second race, at Monza, the cars were painted white with red and blue Martini racing trim instead of flat black with the red and blue trim. Only one 936 was raced in all of the Sports Car Championship races in 1976 and the only place where Porsche raced both cars was the non championship Le Mans 24 hour race. At the seasons first race at Nürburgring the 936 001 suffered a jamming throttle cable which would be its only serious malfunction of the season. Fortunately Reinhold Joest won the race with a turbocharged 908/03 saving the day for Porsche as Stommelen placed fifth in the new 936. In the remaining six races in the Sports car championship the 936 reliability was exceptional and the 936s proved to be unbeatable and won all of the remaining races. 

In 1976 both 936.001 and 936.002 ran the Le Mans 24 hour race. The 936 002 was revised for Le Mans with a high rear deck and a large air scoop above the rear deck. The pear-shaped opening in the air scoop provided cooling air for the engine and the intercoolers. Jacky Ickx and Gijs van Lennep qualified on the pole and led from start to finish in 936.002. The car had a mostly trouble free race with the exception of a cracked exhaust pipe which made the turbocharger inoperative and required a half an hour pit stop to replace it near the end of the race. Even with this half hour stop this car was never in danger of loosing its lead position. However, their extended stop to replace the exhaust delayed them long enough that they did not beat the race record set by Matra in 1973. 

Jurgen Barth and Reinhold Joest were running second with the 936.001 car until it stopped out on the track after 15 hours with both a sheared drive shaft and a seized rocker arm which also damaged a piston. 

After winning all of the races in the 1976 Sports Car Championship and the championship itself in 1976 Porsche did not compete with the 936 racers for the championship again and they were only used for selected races, primarily Le Mans each year. For 1977 both 936 001 and 936 002 received twin turbochargers and revised more aerodynamic bodywork. The twin turbos greatly improved the throttle response and raised the power from 520 to 540 horsepower. The modifications to the body included decreasing the front and rear track width so they could make the body work narrower to reduce the frontal area. They used a short nose piece and a long tail extension for reduce drag on the long straights at Le Mans. Both cars now had the high rear deck and air scoop and they looked the same again. 

The 1977 Le Mans 24 hour race was a real test for the Porsche team. 936 001 entered for Jürgen Barth and Hurley Haywood had problems with the injection pu mp little more than an hour into the race when the mechanical injection pump had a failure that necessitated a 28 minute stop to replace it and dropped 936 001 to 41 place. There was an even worse fate in store for 936 002 which was driven by Jacky Ickx and Henry Pescarolo for it had a connecting rod failure after only 2 hours and 50 minutes of racing and was out of the race. Porsche moved Ickx into 936 001 with Barth and Haywood and the three of them brought the car back into first place after eighteen hours of driving. But at 3:14 with just 36 minutes left to race 936 001 had a head gasket fail and Hurley, Haywood came in with the car only running on 5 cylinders. Fortunately all of the real challengers were out of the race by then or so far back that they could not catch 936 001 even if it sat in the pits for the rest of the race. So that was what it did with the exception of the last two laps so that it would qualify as a finisher .The team disabled the fuel and ignition to the one bad cylinder and at the end of the race Jürgen Barth took 936 001 out for two slow laps and Porsche's fourth victory at Le Mans. 

For the 1978 season the 936 had a newly developed version of the 901/911 engine which was similar to the Moby Dick 935 engine with four valves and water-cooled cylinder heads for increased power and reliability. Each bank of heads had its own water pump and the coolant was circulated from the bottom of the heads to the top, from the exhaust to the intake side, ensuring more even cooling. Each individual cylinder head was electron beam welded to its individual cylinder. This was done to eliminate the cylinder head gasket failures which had become the weakness of these engines when running in long races. These engines were significant in that they were the basis for all further development of 911 racing engines right up through and including the third pace at the 1992 Daytona 24 hour race. 

In addition to the two old cars Porsche built one additional all new 936 for 1978, 936 003, They also modified 936 001 to the same configuration as new 936 003. The body work on both 936 001 and 936 003 was modified to include two large NACA inlets to duct cooing air to the radiators required by the water cooled heads. The vertical fins were replaced by what they called a rear Dornier airfoil with vertical extensions on either side. The air box was made a little smaller and the ducting was changed because the cooling requirements for the engine were different with the water cooled heads. The front nose section was again also made longer in an effort to improve the aerodynamics. 

All three cars were entered in the 1978 Le Mans 936 003 for Jacky Ickx Jochen Mass and Henry Pescarolo, 936 001 updated to 1978 specifications was entered for Jurgen Barth, and Bob Wollek, and 936 002 which was still to 1977 specifications was entered for Hurley Haywood, Peter Gregg and Reinhold Joest. The strategy was to run the cars with a tall final drive gear and a conservative turbo boost, but unfortunately they underestimated the capabiliti es of the Alpine-Renaults. It was obvious right away in the race that the four Alpine-Renaults were faster as the lead Renault had built up a lead of eleven seconds over Ickx on the first lap of the race. And then it got worse for Ickx stopped on the second lap with a throttle pedal that was slow to return and then after 77 laps, the fifth gear pinion broke. Ickx was moved into 936 001 with Wollek and Barth. At the pace that the three drivers drove this car it might have won the race, but it too had a fifth gear pinion failure that took 37 minutes to repair. This car surely would have been the winner had in not been for the transmission failure and after the problem was repaired soldered on to finish second some 80 km behind the winners Jean Pierre Jaussand and Didier Piroini in their Renault-Alpine. 

Henry Pescarolo and Jochen Mass drove 936 003 up to tenth place before its retirement in the 19th hour of the race because of a collision with Mass driving. Haywood, Greg and Joest drove 936 002 to a third place overall even though they were delayed by some minor trouble including a turbocharger failure. The mechanics replaced the turbo in a exceptionally short 13 minutes. 

The two 1978 specification 936s were entered in the 1979 Le Mans race when Essex oil company owner David Thieme offered to sponsor the team for that one race only. The cars were Painted the Essex colors white, blue and red. 936 001 was entered for Bob Wollek and Hurley Haywood and 936 003 was entered for Jacky Ickx and Brian Redman. Unfortunately both cars failed to finish. 936 001 driven by Bob Wollek and Hurley Haywood retired in the nineteenth hour after being in fifth place the proceeding hour. 936 003 driven by Jacky Ickx and Brian Redman in the 1979 Le Mans race. It was disqualified in the seventeenth hour after being in sixteenth place in the preceding hour. It was disqualified because Ickx received outside assistance in the form of a crew member who dropped a pump belt where Ickx could find it out at the edge of the track side where he was trying to repair the car. 1979 was the year that private teams won Le Mans with 935s. Kremer Brother's German team were first with Klaus Ludwig and Bill and Don Whittington as drivers and Dick Barbour's California team was second with himself, Paul Newman and Rolf Stommelen driving. 

The fourth 936 was built for Joest Racing for the 1980 Le Mans race where it was driven to a second place finish by Reinhold Joest and Jacky Ickx. The Joest 936 was a copy of the 1977 version of the 936; but it was not originally called a 936, but instead it was called a 908/80. The car was entered by Joest and sponsored by Martini Racing for Joest and Jacky Ickx to run in the 1980 Le Mans race. There reason given for the car being called a 908/80 was that the car was built as a replacement for the 908/3 and the new c ar for Joest was originally built as an updated 908/3 using a 936 chassis, chassis parts, transmission, engine, fuel and oil tanks, pedals etc. Therefore a new 936 was built and the only difference was that for tactical reasons it was called a 908/80 because Porsche did not want to be in the business of selling 936s to customers and did not want to be pressured by their other racing customers. Later they allowed Joest to call their car 936 004 and provided the Joest and Kremer teams with all of the drawings and data necessary to duplicate the 936s and the Kremers built 936 005 and the Joest team built their 936 C coupe. to run in group C races. 

For the 1980 Le Mans race the Joest team underestimated their competition the Rondeau's. Nobody expected much reliability from the Ford-Cosworth Formula 1 engines powering the Rondeaus. As a result Joest and Ickx ran a pace that was not fast enough. Many feel that the team lost the race in the early stages by running too conservative of a pace when they should have been running a faster pace to build up a safety margin. When team lost fifth gear in the nineteenth hour they had not built up a large enough lead to allow them to regain the lead and the Rondeau of Jean Rondeau and Jean-Pierre Jaussand beat them to the finish by only four minutes. 

For 1980 Porsche AG was planning to go Indy racing with the US. Interscope racing team. The engine for this car was a 2650-cc development of the four valve water-cooled-head engines used in the 936 and Moby Dick in 1978. Porsche, as it turned out, attempted to enter championship cars racing at the wrong time in history, right in the middle of the USAC and CART feud, and the rules for Indy racing changed right out from under them. Porsche had been told that with their six-cylinder engines that they would be allowed to run with a turbo boost of 54 inches of mercury. At the last minute the turbo boost requirements were changed to 48 inches, the same as for the V8 engined cars. Porsche felt that with this last minute change, they did not have time to comply and they probably could not be competitive with the eight cylinder, turbocharged engines and withdrew. Porsche was beaten before they started, not on the track but at the conference room table. 

Porsche didn't let the engine they had designed for the Indy car go to waste though. For 1981, on Peter Schutz, Porsche's managing director's, orders, they dragged the 936s out of the museum once more and updated them to comply with the liberalized Group 6 rules by installing the Indy version of the engine in them. The Indy engine was converted to gasoline and used twin turbochargers for a power output of 620 horsepower. This combination won Le Mans for Porsche for the sixth time in 1981. 

The 1981 running of Le Mans would be the last Le Mans race that the 936 would be eligible for, because from 1982 the race would be for Group C cars. Both 936 001 and 936 003 were again updated for the 1981 running of Le Mans using the more powerful "Indy" engines. Because the five-speed transmission had proven to be problematic they utilized the stronger four-speed version that had originally been developed for the turbocharged 917 Can-Am cars. The two 936s roadsters qualified on the front row, first and second. The 936s were painted in the colors of their new sponsors "Jules". 936 001 was driven by Jochen Mass, Vern Schuppan and Hurley Haywood and 936 003 was driven by Jacky Ickx and Derek Bell. The Mass, Schuppan, Haywood car had a number of problems including a bad spark plug, a faulty injection pump and a clutch failure that required an hour and ten minutes to replace, but they did finally complete the race, but back in twelfth place. This car, 936 001, is now part of Dave Morse’s collection. 

The Ickx-Bell car achieved its target and dominated the race from the start and finished fourteen laps ahead of their closest rival, a Rondeau. This victory gave Porsche six wins at the Prestigious Le Mans 24 hour race and three of those races were won by the 936s. 

The 908/80 (936 004) was also entered in the 1981 Le Mans race with Technocar sponsorship by Reinhold Joest racing for Reinhold Joest and Dale Whittington. It was withdrawn in the fifth hour after being twenty fifth in the proceeding hour because of an accident at the Tertre Rouge S-bend with Dale Whittington driving. 

Inn 1982 the 908/80 was rechristined 936 004. Porsche allowed the 908/80 to be renumbered as 936 004 to be consistent with the other 936s numbering. This car won the 1980 Kylami race and the 1982 German Championship with Bob Wollek driving. 936 004 also helped Bob Wollek to win the 1982 Porsche Cup. This car, 936 004, is now part of the David Morse collection in Campbell California. 

Also during the winter of 1981/1982 Porsche Kremer Racing built 936 005 using the 1981 factory style bodywork. Porsche provided the Kremer's with the 936 drawings and parts necessary to build their 936 005. Rolf Stommelen raced 936 005 in the German Championship in 1982 where they did well and won Wunstorf outright June 6, 1982. Stefan Bellof drove 936 005 for his first turbo drive in the 1982 Hockenheim race. The Kremers still have this car in their collection race ready and beautiful. 

The Kremer brothers also built a couple of Group C cars that they called the CK5 that were largely based upon the 936 components that they raced in the Gro up C races and the German championship. 

Joest also used the drawings and parts from Porsche to build their 936 C which they built in their own workshop. The 936 C ran its first race at Monza in 1982 with Bob Wollek and the Martin brothers with Belga cigarettes as sponsors. 

The Joest 936 C raced at the 1982 Le Mans 24 hour with Belga sponsorship and Bob Wollek and the Martin brothers and made it until the 24th hour when they retired after being fourth the previous hour. The Joest Racing team also entered the 936 C in the 1983 Le Mans for the Martin Brothers and Duez, but an insolvable fuel injection problem forced an early retirement only two hour into the race. The Joest 936 C was raced extensively until 1986 when its current owner, Ernst Schuster, retired The Joest 936 C to his collection. 

936 002 is still in its 1977 Martini Racing configuration and 936 003 in its 1981 Jules configuration and both are part of the Porsche Museum collection and are usually either on display in the factory's museum or on display in some other collection. 936 003 is currently on display at the Porsche racing car collection in the French Musée National De l' Automobile.

2 comments:

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