In 1977, Porsche’s “improvised” Type 936/77 took on the full-court press of four Renaults at Le Mans. Retirements and technical troubles suggested that winning was out of the question. But neither its drivers nor Porsche number 4 believed that.
Against strong opposition from Alpine-Renault and Alfa Romeo, Porsche took the world sports car championship in 1976 with its 936. This was a car it had “improvised,” said Ernst Fuhrmann, made from parts from one car and another, “just to stop others from having it too easy.”
In 1977, Porsche decided not to compete in the full Group 6 endurance series but instead to concentrate on defending its ’76 victory at Le Mans. There Renault, France’s state-owned car company, staked its claim. Renault had acquired the Alpine sports car builder in Dieppe, where it developed tube-framed, sports racers powered by turbocharged V-6 engines. They were fast cars backed by a powerful company that could attract ace drivers.
With its clear focus on Le Mans, at the expense of the other Group 6 races meant that Porsche’s 936 design could be further optimized for the special conditions of the long and fast road circuit in France’s Sarthe district. A major step was the narrowing of the car’s track by 40 mm (1.6 inches) at both ends by fitting shorter suspension wishbones.
This enabled the flanks to be drawn in, making a contribution to a reduction in the car’s frontal area from 18.8 to 17.8 square feet. Yielding benefits on the long Mulsanne Straight, this justified the new designation of 936/77.
Final refinements to the 936/77’s aerodynamics were made in Volkswagen’s wind tunnel in February 1977. These included confirmation of the drag-reduction value of higher cockpit sides, a tweak that had been evaluated but not used for 1976.
In an echo of experiments with the 1962 Grand Prix Porsche, the engineers tested flat discs covering the wheels but these made no difference to the drag. For what was described as “political reasons” the Goodyear tires used previously were replaced by Dunlops.
In an unusual move Porsche’s stylists were allowed to take a hand in the reshaping of the new bodies, built afresh with the aim of keeping weight under control. Lengthening the tail helped bring the drag coefficient down from 0.398 to 0.370 while maintaining downforce, which at speed was 234 pounds at the front and 670 pounds at the rear.
In total, the revised car’s drag was 9% less than the 1976 version, which contributed to an improvement of 16 mph in its top speed as measured at the Paul Ricard track where Porsche liked to test.
While the 1976 936 fed its 2.1-liter 12-valve engine with a single turbocharger, the 1977 version was pressurized by two smaller KKK units which gave better throttle response thanks to their lower inertia. The turbos were mounted far back in the car’s long tail with a single large Porsche wastegate between them.
The exhaust system proper was simpler with this arrangement, while long pipes forward were needed to deliver pressure air to a single large transverse intercooler placed just aft of the cooling fan. Special attention was given to the intercooler and the high-mounted scoop and duct feeding it because every 10º C of cooler air brought a 3% increase in power.
Engine output at 1.4 bar (atmospheres) boost was 525 bhp. Boost was set at 1.3 bar for the race. On the 1.5 bar boost used during practice, the six developed 540 bhp at 8,000 rpm and peak torque of 362 lb-ft at 6,000 rpm. With this power the 936/77 was timed at a top speed of 217 mph at Le Mans.
Extensive tests of one car at Paul Ricard, in March, included a successful 28-hour durability run, with Jacky Ickx and Henri Pescarolo doing the driving. “Our first runs with the narrow-track car were not very positive,” Wolfgang Berger recalled. “The lap times we had achieved with the previous year’s 936 could not be bettered. I was unable to find an objective reason for that.
“Finding a basis for improvements was rather difficult,” Berger added. “We had no opportunity to make a back-to-back test but I was sure that the biggest influence came from the swap of tire suppliers from Goodyear to Dunlop. Retrospective tests were no longer possible, so we could only hope that Dunlop would use our freshly gained data for their further development of tires for Le Mans. We were convinced that our new supplier would construct a tire with the right Le Mans characteristics: low wear and stability at high speeds.”
Tests were made at Paul Ricard with both the normal tail and a special long tail developed for Le Mans—a Porsche tradition. “Our test of the long tail ended abruptly.” Said Berger. “Jacky Ickx lost the complete rear bodywork at high speed and only his great experience prevented him from a nasty crash.
What happened? Having extended the body, we moved the rear wing rearward accordingly, which increased its leverage. We carried over the fasteners for the longer tail from the normal body but their design was not up the increased forces.
They broke and the rear bodywork flew off the car, crashing on the track and smashing into pieces. Although we had to abort the test, we learned that the longer tail did not harm the driveability—and that we needed stronger fasteners.” In fact, they strengthened the entire tail’s underlying structure.
Two 936/77s were prepared for the Le Mans 24 Hours, one weighing 1,615 pounds and the other 1,628. On average this was 26 pounds heavier than the two 1976 cars had been, not including the radio and the tools and spare parts that the cars always carried to help the driver make repairs out on the circuit.
The white cars now carried their red and blue Martini Racing striping atop the fenders instead of down the center of the body as the year before. Among their rivals they faced three works Alpine-Renaults and one semi-private entry plus two American-entered Mirages powered by Renault engines.
“With 3:33.0 Jacky Ickx achieved third-fastest practice time,” Wolfgang Berger recalled, “only one-tenth slower than the second-placed Alpine-Renault of Jacques Laffite and Patrick Depaillier. Pole position went to the Renault of Jean-Pierre Jabouille and Derek Bell, their fastest time being 3:31.7.
Driven by Jürgen Barth and Hurley Haywood our second car was clocked at 3:40.0, which meant seventh place on the grid. Renault’s superiority was manifested in the first six rows, in which five of their cars appeared, including the Mirage using the same engine. Our appearance with two 936/77s and one 935 for Rolf Stommelen and Manfred Schurti was modest in comparison.”
“As every year,” said Jürgen Barth and Berndt Dobronz in their book about the 936, “celebrations were the order of the day after the final training. Martini & Rossi invited selected drivers from all teams to the Martini Pavilion on the track at 11 p.m., immediately after the last training session.
There was plenty of high-proof drink and enjoyment was not overlooked. As always, ‘by accident’ a pile of raw eggs and other niceties were available that were ideal for throwing. A huge food battle quickly developed. Seasoned racers fooled around like children but none was embarrassed.
Why not? The drivers had completed practice and qualification on one of the most dangerous race tracks in the world—and they were still alive! At that time this was not a matter of course so the drivers enjoyed every minute of the party.”
In 1976, Renault had fielded only a single Alpine-Renault A442 at Le Mans, which obligingly retired. “At Porsche, however, nobody was so naive to believe that this would happen again in 1977,” said works tester and driver Jürgen Barth, “because now there were four A442 Turbos at the start, which opened up completely different tactical possibilities for the Alpine-Renault team. We expected that a French car would rush away from the field at high speed right from the start to lure Porsche into a chase at similar speed.”
Porsche’s strategy was more circumspect. Of its two entries, one with Jacky Ickx and Henri Pescarolo would drive for victory while the other handled by Hurley Haywood and Jürgen Barth was to play a backup role. Sports director Manfred Jantke gave the guidance at the drivers meeting on Friday:
“Don’t let the four Renaults make you nervous. During the first hours, drive at the pace specified by the team management. Even if one of the Renaults should play the ‘rabbit’ as expected, we have to maintain discipline. You must wait until the pit at Mulsanne Corner signals the attack.”
Porsche saw a clear advantage in terms of the relative reliability of the cars. It was confident that not all four Renault Alpines would get through the night without problems. In fact, one of them obliged by stopping on the very first lap with a fire from a turbocharger oil leak.
As forecast by Jantke, Jean-Pierre Jabouille’s Alpine rushed into the lead immediately after the 4:00 p.m. start. Jacky Ickx was third in 936-002, ahead of the other two Renaults of Jacques Laffite and Patrick Tambay and 936-001 with Jürgen Barth behind the wheel. Soon Ickx overtook Tambay and moved into second place. In his next laps the Belgian even managed to gain ground on the leading Renault with times of 3:47.
About an hour into the race, halfway through his first driving stint, Jürgen Barth brought his 936/77 into the pit, declaring that his engine had lost power. He had already warned the team of this at a brief stop half an hour earlier. Lifting the rear deck, the mechanics probed all obvious elements and found none of the usual faults.
It fell to the head of the Bosch Racing Service, former Borgward team mechanic Fritz Jüttner, to diagnose a fault with the injection pump. A later autopsy of the pump disclosed the failure of a circlip only 4 mm in diameter that affected the lever that controlled the unit’s delivery pressure. It was the first time this failure had occurred.
After a stop lasting 28:50 the Number 4 Porsche was on its way again, Barth still at its wheel to complete his two-hour stint. He resumed his race in 41st place, clearly destined to finish far from the prize positions. Meanwhile, Ickx handed over Porsche Number 3 to French ace Pescarolo, who had been recruited from Renault’s 1976 squad. In a stirring drive he chased, caught and passed future Porsche star Derek Bell in the leading Renault. All was now well in the world of Porsche.
Only ten minutes later Pescarolo radioed: “Engine trouble. Coming into the pits.” Trailing a cloud of smoke, he clattered to a halt. Inspecting the engine, mechanics shook their heads. A broken connecting rod had sliced through the block. Subsequent analysis disclosed that the surface of the titanium rod had not been polished enough to remove all the stress-raisers—a process even more critical with titanium than with steel.
At this juncture the race was decided in favor of the Alpine-Renaults, three of which were cruising in the lead. In spite of his tachometer’s failure, forcing him to shift by ear, Barth’s solid laps in the Number 4 Porsche had made up ground. He was lying in 15th place, a daunting nine laps behind the leader. “Three hours after the start it seemed that the result was already decided,” recalled Hans Mezger. “No one believed that Porsche would be able to win this race.”
For Porsche chief Ernst Fuhrmann, the outcome was not foreordained. At 8:20 pm, more than four hours into the race, Barth came back to the pits as planned and climbed out of the 936/77. Jacky Ickx stood ready to take over instead of Haywood. The Porsche team had decided to list the Belgian as the third driver of its Number 4 936/77.
Explicitly instructed by Fuhrmann to “Win or bust!” Jacques-Bernard Ickx, known as Jacky, contested the race of his life. Porsche had nothing to lose, so the plan for 936-001, which had been entirely defensive, gave way to an all-or-nothing strategy.
Porsche allowed Ickx to increase the boost pressure from the cruising 1.3 bar to the qualifying 1.5 bar, which brought an additional 20 horsepower. Between 8:21 p.m. and 11:13 p.m. he drove a double stint, only interrupted by a fuel stop of 50 seconds at 9:46 p.m. Ickx made one quick lap after the other.
Despite still-heavy traffic, he also broke the lap record with a time of 3:36.8. And that despite the flap of the rear wing being set five degrees flatter than that of his original mount, giving oversteer that the Belgian didn’t relish.
When Ickx returned to the pits after almost three hours at the wheel, the 936/77 was up to sixth place. On average he had driven lap times of 3:43 and was thus a good ten seconds faster per lap than the three remaining Alpine-Renault A442 Turbos, which were in cruising mode thanks to their vastly better positions and the remoteness of the Porsche challenge. Even Hans Mezger was calling the Porsche position “almost hopeless.”
Ickx’s great effort was almost stalled by an infraction of the rules. He attacked the curbs with such vigour on his all-out laps that the jolts broke both rear-view mirrors away from their front-fender pylons. A delegation from the organizing club appeared in the Porsche pits, stating that if the rear-view mirrors stipulated by the regulations were not installed, the Porsche would be immediately disqualified.
The mechanics found some small mirrors, which they screwed to the tops of the doors on both sides of the cockpit. This satisfied the rules, though they showed the driver little more than the rear wing.
“Ickx amazed us all,” said Norbert Singer. “He was in the car for more than seven and a half hours during the night. He broke the lap record time after time in the dark. He spent a total of nearly 11 hours in the car, having taken it over four and a half hours after the start. Later he told us that it was the hardest race of his life.” Testimony to this was his loss of 18 pounds of body mass.
By the ninth hour the 936/77 was up to fourth place. At 5 o’clock in the morning, after 13 hours, it was second but still 7½ laps behind the leading Alpine-Renault. Rain had come during the night but Ickx drove on with lap times a little over four minutes using rain tires. Both Ickx and Barth complained about water entering the turbochargers, which caused the engine to drop out briefly. Nor was the cockpit well shielded from the rain, drenching the drivers more and more during a stint.
When the rain finally subsided around 8 a.m., slicks were installed at another stop at 8:36 a.m. On the now increasingly drying course, Jacky’s times settled at 3:50. After a stint of almost four hours he finally climbed out of the 936/77 at 9:09 a.m., exhausted. Ickx had been at its controls right up to the limit, for the Le Mans rules did not allow a driver to exceed four hours at a time.
In the morning, a runner-up finish was the likely outcome, worthy in the circumstances. When Jürgen Barth took over from Ickx he did a fine job of fending off an attack from the rear by one of the yellow Alpines, holding on to second place. But just as dawn was breaking the leading Renault retired with an engine failure and Porsche Number 4 was in front.
It had a margin of only a lap over the sole surviving Alpine-Renault but at noon, with four hours’ racing remaining, this too broke—leaving the 936/77 unchallenged. Ickx had a final stint of an hour and a half followed by a similar one for Barth, after which Haywood took over to drive to the finish.
With 40 minutes of the 24 hours remaining the dismayed Porsche pit staff saw a gout of smoke from the 936/77 at the Ford Chicane just before the pits. Hurley Haywood drove straight into the pit lane. While mechanics worked on the car he and his teammates were reassured that their margin was so great that no rival racer had a chance to cover as much distance as theirs had.
The piston in cylinder number three had seized. Its spark plug was removed and its fuel injection deactivated. They would wait in the pit until the last minute to drive to the finish. But many questions remained, as Norbert Singer related: “How serious was the piston seizure? Would the engine start again, and if it would, how long would it run?
We were preoccupied by all these questions when Jürgen Barth took the wheel for the last two laps.” Barth was chosen because the man who was able to get a car running again in the middle of the African bush was the driver most likely to be able to get the Porsche going again if it stopped along the way.
One more Le Mans ritual had to be satisfied. This required that a car cross the line under its own power and that its final lap be completed in no more than three times the best lap time registered during qualification. Barth and Haywood drove a 3: 40.0 lap in training, so the last lap had to be completed within 10:20.0. Since Hurley Haywood had already crossed the finish line when entering the pits, the 936/77 Number 4 had to go through two full laps, finishing on a flying lap.
With Barth checking the stopwatch taped to his steering wheel, Porsche chassis 936-001 successfully did the necessary and was flagged home the winner at Le Mans. During its 20 stops the car had been at rest in the pits for 1 hour and 31 minutes. Barth had driven for 8 hours and 40 minutes, Haywood for 3 hours and 12 minutes and Ickx for 10 hours and 37 minutes. If ever perseverance and skill were rewarded, this was such an occasion.
Immediately after crossing the finish line Jürgen Barth, still in the car, received a champagne shower from the mechanics. Hurley Haywood and Jacky Ickx scrambled over the pit wall to the victorious Porsche and joined in the champagne inundation. Some of the surrounding gendarmes climbed over the nose, to the cockpit and pulled the soaked Barth out of the car. Everyone wanted to congratulate the three drivers—touching their shoulders, shaking hands, hugs—jubilation!
Photos courtesy: Ludvigsen Partners, Jürgen Barth and Bernd Dobronz
SPECIFICATIONS
| Body | 3-piece fiberglass body |
| Chassis | multi-tubular aluminum spaceframe |
| Suspension (fr/r) | double wishbones, variable rate coil springs, Bilstein telescopic shock absorbers, anti-roll bar |
| Steering | rack-and-pinion |
| Weight | 700 kilo / 1,543 lbs |
| Length / Width / Height | 4,960 mm (195.3 in) / 1,920 mm (75.6 in) / 1,270 mm (50 in) |
| Wheelbase / Track (fr/r) | 2,410 mm (94.9 in) / 1,540 mm (60.6 in) / 1,515 mm (59.6 in) |
| Fuel tank | 160 Liter (42.3 Gallon US / 35.2 Gallon Imperial) |
| Wheels (fr/r) | 10.5 x 15 / 15 x 15 |
| Tyres (fr/r) | 265/565 – 15 / 340/600 – 15 |
| Engine | Type 935/73 B6 |
| Location | Mid, longitudinally mounted |
| Construction | aluminum block and head |
| Displacement | 2,142 cc / 130.7 cu in |
| Bore / Stroke | 87.0 mm (3.4 in) / 60.0 mm (2.4 in) |
| Compression | 7.0:1 |
| Valvetrain | 2 valves / cylinder, SOHC |
| Fuel feed | Bosch Fuel Injection |
| Lubrication | Dry sump |
| Aspiration | KKK Turbo |
| Power | 540 bhp / 403 kW @ 8,000 rpm |
| Torque | 471 Nm / 347 ft lbs @ 6,000 rpm |
| BHP/Liter | 252 bhp / liter |
