Guide: Porsche 917/20
Background
Although there was little doubt that, with the formidable 917, Porsche had the fastest Sports Prototype of its era, a performance gulf existed between the crushingly effective short-tailed 917 K and the slippery 917 L created to win at Le Mans.
On most circuits, the 917 K’s excellent handling characteristics would have seen it vanquish the 917 L with ease. However, the unique nature of the high speed Le Mans circuit meant the Langheck, which was much quicker in a straight line, was able to more than recover any time lost in corners.
This disparity in lap times gave Porsche the idea to try and create a 917 that was as good through the corners as the Kurzheck, but able to match the Langheck for top speed. Management gave the green light to develop such a car a couple of weeks after the 1970 Le Mans race.
The result was the ugly duckling of the 917 family, the 917-20, which quickly became known as ‘The Pig’.
At the time, Porsche were spending vast sums developing the 917. In addition to constant refinements for the Kurzheck, they were working on revised bodywork for the Langheck and experimenting with turbocharging for a Group 7 programme. A massive 16 cylinder engine was also in the pipeline.
Adding the 917/20 into the mix only increased the concern of the company’s bean counters.
Bodywork
Like the subtly reworked 1971 iteration of the 917 L, the 917/20 was a collaboration between Porsche’s Design Department and the SERA R&D organisation in Paris headed by pioneering aerodynamicist, Charles Deutsch.
The French design team created a dumpy looking machine that, although aerodynamically efficient, lacked the elegance of other 917 derivatives.
It had a shortened nose with a flattened leading edge and a discrete wraparound chin spoiler at each corner. There was also a bigger rectangular intake for the radiator and more steeply raked upper nose that concealed the radiator vents. As per the 917 L, headlights were mounted side by side as opposed to in the stacked fashion adopted by the 917 K.
One aspect of the design that SERA were not able to modify was the domed cockpit profile.
As a result of its dramatically widened bodywork, the Pig’s wheels were set deep within the arches to mimimise airflow disruption (track dimensions were the same as every other 917). The 917-20 was in fact so wide that it did not fit in Porsche’s regular transporter.
Unlike the 1971 Langheck, the Pig had a severely shortened tail, no rear wheel spats and the vertical stabilising fins were not bridged with a central spoiler.
Chassis
Under the skin was the 917’s familiar tubular alloy spaceframe which was permanently gas-pressurised to detect cracks.
Double wishbone suspension incorporated titanium coil springs with adjustable Bilstein-de-Carbon shocks and magnesium uprights.
Girling brake calipers and ventilated discs were fitted.
The Firestone-shod centre-lock wheels were mounted on titanium hubs. 15 x 10.5-inch magnesium alloy rims were used at the front with wider 17-inch rims installed at the back.
For the more tightly packaged 917/20, the back end of the car was reconfigured to accommodate the mandatory luggage suitcases, the spare wheel and the oil tank. A rear-mounted transmission cooler was installed as per the Langheck 917s.
Engine / Geabox
Hans Mezger’s air-cooled DOHC 180° Flat 12 used by the 917 brimmed with advanced alloys. It employed dry-sump lubrication, two valves per cylinder and mechanical Bosch fuel-injection with two separate ignition distributors to feed the 24 spark plugs.
Although a new Type 912/11 engine of 4999cc became available shortly after the Pig debuted at the 1971 Le Mans Test, Porsche stuck with the a 4907cc unit for the 24 Hour race in June. 4.9-litre engines hooked up to five-speed gearboxes were also used for the trio of Langhecks that attended in 1971.
However, the special Type 912/00 motor fitted to the Pig was slightly different to the familiar Type 912/10 engine and, thanks to a slightly higher state of tune, pumped out 600bhp at 8300rpm compared to 570bhp at 8100rpm.
Interior
Like every 917, the Pig’s cockpit was notionally suitable for two people on account of the tiny, untrimmed seat mounted on the left-hand side. The driver was forced to sit at an almost 45° angle with his feet hung out over the front axle.
Aside from a little padding on the driver’s seat, there was no upholstery, no sound deadening and no creature comforts.
The main instruments were displayed in a simple binnacle directly behind the leather-rimmed three-spoke steering wheel.
As usual for the 917 range, the Pig was right-hand drive with a right-hand gear lever.
Weight / Performance
Weight was trimmed down to 813kg. Top speed was 225mph and 0-62mph took under four seconds.
1971 Le Mans Test
With no time to spare ahead of the Le Mans Test weekend (April 17th and 18th), the 917/20 (chassis 001) arrived in France having never turned a wheel in anger. It was painted a plain white colour scheme that accentuated its rather unflattering appearance.
In addition to the 917/20, four other 917s were in attendance. Three of these were run under the John Wyer Automotive Engineering banner (JWAE). The other was a privateer 917 K from Zitro Racing.
The JWAE machines comprised a Gulf-liveried 917 K which was used to trial a few bodywork updates. There were also two plain white cars: another 917 K (this one with a trick magnesium chassis) and a 917 L which featured some new titanium suspension parts and the Bilstein-de Carbon shocks.
Jackie Oliver, Derek Bell, Gijs van Lennep and Jo Siffert were on hand to drive the JWAE cars.
Siffert also had a go in the 917/20, together with Porsche factory test driver, Willi Kauhsen. Neither were particularly happy with the untested car; stiffer rear springs, altered brake bias and some spoiler adjustments gradually improved things.
All five cars present used the latest drilled and vented brake discs.
While Jackie Olver went on to smash the existing lap record by an astonishing nine seconds in the latest 917 L, the unproven 917/20 was given a more gentle shakedown. It posted fifth quickest time of the weekend, after which it was given an engine transplant ahead of Sunday afternoon’s 3 Hour race.
1971 Le Mans 3 Hours
The Le Mans organisers had decided to hold a 3 Hour race to try and improve participant and spectator attendance.
Porsche had originally planned to run the 917 L and 917/20, but the Langheck was withdrawn after practice. Instead, Gijs van Lennep (who had been expected to race the Langheck) would join Willy Kauhsen in the Pig.
In the absence of the 917 L, the 917/20 was promoted to pole position ahead of the Georg Loos / Franz Pesch Ferrari 512 M (GELO Racing), the Jose Juncadella / David Hobbs Ferrari 512 M (Escuderia Montjuich) and the Andre Wicky / Max Cohen-Olivar Porsche 908/02 (Wicky Racing Team).
In the race, Kauhsen immediately screamed into the lead ahead of the Loos 512 M.
By the end of the first lap, Kauhsen was well ahead of the dicing Ferraris behind him.
After one hour (16 laps), Kauhsen stopped for fuel and van Lennep took over, still with a healthy lead. The Dutchman continued to pull away from the rest of the field and after 90 minutes of racing the 917/20 had lapped the entire field.
Unfortunately, 15 minutes later, the Pig cut out at Arnage and could not be re-started. Kauhsen and van Lennep were out of the race.
With several of the other more fancied runners also falling by the wayside, victory ultimately went to the Claude Ballot-Lena / Guy Chasseuil Porsche 908/02 entered by Auguste Veuillet / Sonauto.
Build up to the 24 Hours
Afterwards, the 917/20 returned to Stuttgart where Anatole Lapine, head of Porsche’s Design Studio, lobbied to paint the car a special colour scheme. Hans-Dieter Dechent (boss of the Martini Racing Team) had already stated he did not want the ugly car running in Martini colours at la Sarthe.
Lapine’s humorous idea was to paint the 917/20 in the style of a butcher’s diagram that listed the different cuts of pork. His concept was approved and the Pig duly arrived at Le Mans a few weeks later where it became the most photographed car in the race.
1971 Le Mans 24 Hours
After the fiery opening lap accident that marred the 1970 Le Mans 24 Hours and claimed the life of John Woolfe, the 1971 event got underway with a rolling start. In previous years, the drivers had dashed across the track, fastened their seatbelts (or not) and driven off.
The 1971 contest took place over the weekend of June 12th and 13th. Porsche had won the previous year’s event (their maiden victory) and arrived with six works 917s that would run as JWAE / Gulf Oil and Martini International Racing Team entries.
Three Langhecks were in attendance: one 917 K with a magnesium chassis, one 917 K with a standard chassis and the 917/20 resplendent in its new pink colour scheme.
The 917/20 was allocated to Willi Kauhsen and Reinhold Joest. It formed part of the three-car Martini entry.
After the Pig initially failed scrutineering, the ride height was raised a little and it was cleared to race.
Kauhsen qualified the car seventh. Ahead of him were the trio of 917 Langhecks which were followed by the Penske Ferrari 512 M, the mag chassis 917 K and the Escuderia Montjuich Ferrari 512 M.
Kauhsen was still in seventh at the end of the first lap, but had dropped to ninth by the end of the first hour. With three hours gone, the Pig was back in eighth position and at quarter distance had risen to fifth.
However, as midnight approached, the 917/20, which had been lying third, began to show symptoms of throwing off its cooling fan (as Elford’s Langheck had already done). Fortunately, the Martini crew were able to catch it in time and replace the retaining bolts.
By 3am, the Pig had recovered to fifth position, but 19 minutes later its race was over; approaching Arnage, Joest found he had no brakes, went up the escape road, hit the barrier and incurred sufficient damage that the car could not continue.
Nevertheless, Porsche went on to claim their second Le Mans win in succession thanks to the mag chassis Martini 917 K of Gijs van Lennep and Helmut Marko. They finished three laps clear of the JWAE Gulf Kurzheck driven by Richard Attwood and Herbert Muller.
Subsequent History
After its appearance at Le Mans, the 917/20 was sent back to Porsche and repaired. It was subsequently restored by Jerry Sutterfield on Porsche’s behalf between 1983 and 1985 before taking up residence in the factory museum.
Text copyright: Supercar Nostalgia
Photo copyright: Porsche - https://www.porsche.com
