Porsche 917

Porsche 917
Porsche
aka	917K, 917L, 917LH, 917PA Spyder, 917-10, 917-20, 917-30
Production	1968-1975
Class	Racing
Body Style	Two-door coupe, 'K' for short-tail, 'L' for long-tail (endurance racing) Two-seat open
Length	4120 mm (1969)
Width	2080 mm (1969)
Height	940 mm (1969)
Wheelbase	2300 mm (1969)
Weight	800-1000 kg
Transmission	5-speed manual PDK double-clutch sequential
Engine	Type 912 4.5 litre flat-12 (1969) 4.9 litre flat-12 (1970) 5 litre flat-12 (1971) 5.0 litre flat-12 turbo (1972) 5.4 litre flat-12 turbo (1973)
Power	630 bhp (1969) 1500 bhp (1973)
Similar	Lola T70 Ferrari 512 Ford GT40
Designers	Ferdinand Piech, Helmuth Bott (chassis) Hans Mezger (engine)

The Porsche 917 is a racecar that gave Porsche its first overall wins at the 24 hours of Le Mans in 1970 and 1971. Powered by the Type 912 flat-12 engine of 4.5, 4.9, 5 or 5.4 litres, the long-tailed version was capable of a 0-62mph time of less than 2.5 seconds and a top speed of over 248 mph (394 km/h).

In the 1973 CanAm series, the turbocharged version Porsche 917/30 developed over 1100 bhp, and as much as 1500bhp in qualifying tune.

The 917 is one of the most iconographic sports racing cars of all time largely for its high speeds and high horsepower outputs and was even made into a movie star by Steve McQueen in his film Le Mans.

History

In an effort to reduce the speeds generated at Le Mans and other fast circuits of the day by the 7 litre Ford prototypes, as well as to entice manufacturers who were already building 3 litre Formula One engines into endurance racing, the Commission Sportive Internationale (then the independent competition arm of the FIA) announced the World Championship of Makes would be run for 3 litre open prototypes for four years from 1968 through 1971.

Well-aware that few manufacturers were ready to immediately take up the challenge, the CSI allowed the participation of 5 litre sports car manufactured in quantities of 50 in the Sport category, which was called Group 5, targeting existing cars like the aging Ford GT40 and the newer Lola T70 coupe.

In April 1968, the CSI announced that the minimal production figure to compete in the Sport category of the World Championship of Makes (later the World Sportscar Championship) was reduced from 50 to 25 starting in 1969 through the planned end of the rules in 1971, mainly to allow the homologation of the Ferrari 275 LM and the Lola T70 (which was not manufactured in sufficient quantities, unless the open Can-Am T70s were counted as well) as there were still too few entries in the 3 litres Prototype category.

Starting in July 1968, Porsche made a surprising and very expensive effort to take advantage of this rule. As they were rebuilding race cars with new chassis every race or two anyway, they decided to conceive, design and build 25 versions of a whole new car for the Sport category with one underlying goal: to win its first overall victory in the 24 Hours of Le Mans. In only ten months the Porsche 917 was developed, based upon the Porsche 908, with remarkable technology: Porsche’s first 12-cylinder engine, and many components made of titanium, magnesium and exotic alloys that had been developed for lightweight hillclimb racers. Other ways of weight reduction were rather simple, like a gear lever knob made of Balsa wood.

On March 12, 1969, the first 917 was displayed at the Geneva Motor Show, painted white, with a green nose and black #917. Brief literature on the car detailed a cash price of DM 140,000, approximately £16,000 at period exchange rates - or the value of about 10 Porsche 911s.

When Porsche was first visited by the CSI inspectors only three cars were completed, while 18 were being assembled and seven additional sets of parts were present. Porsche argued that if they assembled the cars they would then have to take them apart again to prepare the cars for racing. The inspectors refused the homologation and asked to see 25 assembled and working cars.

On April 20 Ferdinand Piëch displayed 25 917s parked in front of the Porsche factory to the CSI inspectors. Piëch even offered the opportunity to drive one of the cars, which was declined.

1969

In testing, it soon appeared that the Porsche 917 did not work well on the racing track. Brian Redman recalls that "it was incredibly unstable, using all the road at speed." Many thought that the 4.5 litre engine was too much for the frame. The suspension and the stability of the frame was suspected, but modifications did not improve the problem. As the 917 was 30km/h faster than anything previously built for Le Mans, it was finally found out that the long tail body was generating significant lift on the straights. As with former underpowered Porsches, the 917 aerodynamics had been optimized for low drag in order to do well on the fast straights of Le Mans, Spa, Monza and elsewhere. The significance of downforce for racing was not yet fully realized even though CanAm and F1 cars had literally grown wings at that time.

Before its competition debut on 11 May 1969 in the 1000km Spa, the weather conditions prevented further improvements in tests. Siffert/Redman managed to clock an unofficial laptime of 3:41,9 which would have beaten the pole of 3:42,5 set by a Lola, but they chose to use the 908LH long tail with which they won the race and set fastest lap at 3:37,1. Gerhard Mitter/Udo Schütz started the race from 8th, but the already ailing engine failed after one lap.

Porsche 917 in 1000-km-Race at the Nürburgring 1969

Three weeks later for the 1000km Nürburgring, all works drivers preferred the 908 over the 917 which was, despite some modifications, not suited for this twisty track. As it was necessary to promote the car in order to sell the surplus ones, Porsche asked BMW for the services of their factory drivers Hubert Hahne and Dieter Quester. They practised, but Munich declined the permission for the race, so Englishman David Piper and Australian Frank Gardner were hired on short terms. They drove the 917 to a eighth place finish behind a Ford and an Alfa, while the factory's armada of six entered 908/02 spyders scored a 1-2-3-4-5 win after the only serious competition, a sole Ferrari 312P, had failed.

At the 1969 24 Hours of Le Mans, the 917s were quickest in practice and lead the race for hours, but did not make it through the night. At the end, Hans Herrmann's 908 remained as the only Porsche that could challenge for the win, but Ickx' more powerful Ford won once again, by a mere 120 meters. Sadly, John Woolfe suffered a fatal accident in his privately entered 917 in lap one.

During June 1969, Enzo Ferrari had sold half of his stock to FIAT, and used some of that money to build 25 cars powered by a 5 litre V12 in order to compete with the Porsche 917: the Ferrari 512 would be introduced for the 1970 season.

At that time, the 917 already had several races under its belt, yet no success. The first win came only in the last race of the championship season, at Zeltweg. Jo Siffert/ Kurt Ahrens succeed in the privately entered Porsche 917 of German Freiherr von Wendt. At that time, the factory had started to focus on development, leaving the time-consuming trips to races to customer teams.

1970

Disappointed by the poor results of the 917 in 1969, and facing a new competition, Porsche concluded an agreement with John Wyer and the Gulf Team, which became the official Porsche team, and also the official development partner. During tests at Zeltweg, where the car had won its only race at that time, Wyer's engineer John Horsmann had the idea to increase downforce at the expense of drag. (Reportedly he had noticed that after a test, no insects had hit the existing tail, therefore the air was not reaching it.) A new wedge-shaped tail was molded with aluminum sheets taped together. This new short tail gave the 917 much needed stability. The plastic engine intake cover had already been removed. The new version was called 917K (Kurzheck).

Also, a new low drag version of the 917 was developed for Le Mans with support from the external consultant Robert Choulet. The 917LH (Langheck) featured a spectacular new "Long Tail" body including partially covered rear wheel arches which had very low drag, yet better stability than the 1969 version. A few 4.9 litre engines were available for some cars, but these proved to put too much strain on the gearboxes.

Early in the race, the factory Ferrari entrants eliminated themselves after a collision. The two Porsche factory teams, Gulf-Wyer and Porsche Salzburg, continued to battle each other. At the end it was the red and white #23 917K of Porsche Salzburg, with the standard 4.5 litre engine, safely driven by Stuttgart's own Hans Herrmann and Englishman Richard Attwood through the pouring rain, that finally scored the first overall win at Le Mans, in a wet race that saw only 7 ranked finishers. Martini's blue 917LH with a green/blue "psychedelic Hippie" design came in 2nd.

Towards the end of the 1970 season, Ferrari entered some races with a new version of the 512, the 512M (Modificata). The 512M had a new bodywork built on the same aerodynamic doctrine as the Porsche 917K. At the end of 1970 the 512M was faster than the 917s, at least on some tracks.

During the 1970 season the FIA decided to eliminate the loop-hole Sport category at the end of the 1971 season, when the rules expired, so the big 917s and 512s would have to retire at the end of the year. Surprisingly, Ferrari decided to give up any official effort with the 512 in order to prepare for the 1972 season. A new prototype, the 312 PB, was presented and entered by the factory in several races. But many 512s were still raced by private teams, most of them converted to M specification. The Gr.5 category, would temporarily disappear until 1975, when it was re-amended for production cars.

Being cheaper than the 917K, the 512M appeared a bargain for customers at the end of 1970 - a consolation that was hardly imaginable only two years previously. Porsche, an underdog for 20 years, had turned itself into the new superpower of sports car racing with the 917. In addition, the lightweight and compact Porsche 908/3 were available for the slow and twisty tracks of Nürburgring and Targa Florio.

1971

Porsche 917/20 "Pink Pig", in Stuttgart-Zuffenhausen Museum

A new challenger to the 917 appeared early in the season: Roger Penske had bought a used 512M chassis that was totally dismantled and rebuilt. The car was specially tuned for long races, receiving many unique features among which were a large rear wing and an aviation-inspired quick refueling system. The engine was tuned by CanAm V8 specialist Traco and probably able to deliver more than 600 hp (450 kW). As of today it's impossible to know to what extent Penske's initiative was backed by Ferrari works. This 512M, painted in a blue and yellow livery, was sponsored by Sunoco and the Californian Ferrari dealer Kirk F. White. Driven by Penske's lead driver Mark Donohue, it made the pole position for the 24 Hours of Daytona and finished second despite an accident. For the 12 Hours of Sebring the "Sunoco" made the pole but finished the race at the sixth position after making contact with Pedro Rodriguez's 917. Despite this misfortune the car had proved to be a serious opponent for the 917. Not only was this car the fastest on track in Daytona and Sebring, but it was also the car that had the shortest refueling time.

The presence of the 512M "Sunoco", as well as the Alfa Romeo 33/3 which won Brands Hatch and the Targa Florio, forced Porsche to pursue their efforts in research and development: tails of the 917K and the 908/3 were modified with vertical fins, and the 917 LH aerodynamics received further improvements. New chassis made of magnesium were developed, even though this material could burn vigorously in the instance of a fire.

A heavily modified car, the 917/20, was built as test-bed for future CanAm parts and aerodynamic "low-drag" concepts. The 917/20 which had won the test race at Le Mans was painted in pink for the 24 hours race, with names of cuts of meat written in German across it in a similar fashion to a butcher's carcass diagram, earning it the nickname "Der Truffeljäger von Zuffenhausen" (The Truffelhunter of Zuffenhausen) or just plain "Pink Pig".

Yet at Le Mans, once again it was not the new machinery that won. The white #22 Martini-entered 917K of Helmut Marko and Gijs van Lennep, equipped with a magnesium frame, set an overall distance record that still stands.

1972 & 1973 Can-Am

As the new rules for the 3-litre prototypes were not favorable to their existing low-weight, low-power Porsche 908, Porsche decided against developing a new high power engine that could keep up with the F1 designs of the competition's - at least in naturally-aspirated form. In 1976 they would return to sport-prototype racing with the turbocharged Porsche 936 racecars after the engines were tested in Porsche 911 versions.

After their successes with the 917 mainly in Europe, Porsche instead decided to focus on the North American markets and the Can-Am Challenge. For that series, larger and more powerful engines were needed. A 16-cylinder with about 750hp was tested, but a turbocharged 12-cylinder had initially the same power, with more to come.

The turbocharged 850hp 917/10 entered by Penske Racing won the 1972 series with George Follmer, after a testing accident injured the knee of primary driver Mark Donohue. This broke the five-year stranglehold McLaren had on the series. The further evolution of the 917, the 917/30 with revised aerodynamics, a longer wheelbase and an even stronger 5.4 litre engine with up to 1500 horsepower won the 1973 edition, winning all races but two with a fully-fit Donohue driving. Most of the opposition was made of private 917/10 models, as McLaren had already left the series to concentrate on the Indy 500 and F1.

The 917's domination, the oil crisis and fiery tragedies like Roger Williamson's in Zandvoort pushed the SCCA to introduce a 3 miles per US gallon minimum fuel consumption rule for 1974. Due to this, the Penske 917/30 competed in only one race in 1974, and some customers retro-fitted their 917/10 with naturally aspirated engines.

The 917/30 was the second most powerful and fastest sports car racer ever built and raced. The 5.4 litre 12 cylinder twin-turbocharged engine could produce 1500 bhp with twin turbochargers run up to full boost, a simply astonishing 39 p.s.i, though it usually raced with around 1100bhp to preserve the engine. The 917/30 dominated in the Can-Am series during the 1973 season. The 917/30 could go from 0-60 mph in 2.4 seconds, 0-100 in 3.9 seconds and 0-200 in 10.9 seconds and on to a top speed of 245 mph+. These staggering levels of performance, the attendant fuel thirst of the engines, and ever increasing risk, has led to the 917/30 sometimes being cited as the car that killed Can-Am racing.

The Road Cars

The 917 may not be the first word in practicality, but at least two examples were converted into road cars. The first was converted for Count Gregorio Rossi di Montelera, a close customer of the Porsche company and also major investor and sponsor of the Porsche-Martini racing team which dominated numerous fields of motorsport in the Seventies and Eighties. The brief presented by Rossi was a 917K as close to the racing car as possible, with only minor modifications, such as a silencer and a small amount of road-rash protection for air vents, which made the job ever harder for the Porsche Motorsport Department. The car selected for conversion was chassis 917.030, which was built in January 1971 but only raced once, by Helmuth Marko and Gerard Larrousse, in Martini-Porsche colours. It was the designated development car for anti-lock braking systems, and spent most of its days pounding the Weissach test track, until being mothballed until being called into service as the road car. Rossi ordered that the car be painted silver, as Germany's national racing colour is silver. The only place where the barely-modified 917K reached roadworthiness conditions was Alabama, where it was registered on Alabama plate 61-27737.

The second 917 converted for road use was another 917K, converted for German Joachim Grossbad. The car was painted pure white with black wheels, and featured the same modifications as the Rossi car, but with a more luxurious interior. It was given German registration CW-K 917.

Other uses

In 9th August 1975, Porsche and Penske would give the Can-Am car its final send off in style when they took their 917/30 to Talladega to break the FIA speed record on a closed circuit with Mark Donohue driving, the speed reached was 245 mph. As well as being the last official outing for the 917, it was the last major accomplishment for Donohue before his fatal accident in practice for the Austrian Grand Prix a week later. The record would stand for the next 22 years.

Also, several 917 coupés as well as 917/10 (powered by turbos or NA engines), were run in Europe's Interserie until the mid-1970s.

Many of the 917 leftover parts, especially chassis, suspension and brake components, would be used to build the Porsche 936 in 1976.

In 1981, German team Kremer would give the 917 its final farewell, with a coupé especially built for the Group 6 category and mechanicals sourced from the factory. It was competing at the 1981 24 Hours of Le Mans before retiring with mechanicals troubles.

Besides the Le Mans (film), another well-known appearance of the 917 in movies was in Herbie Goes to Monte Carlo. Driven by Bruno von Stickle (Eric Braeden), and painted in the colors of Germany's national flag, it was perhaps the most formidable entry in this fictitious Trans-France Race. The car shown in the movie was not a real 917, though, but a replica known as the US produced Laser 917. As the Laser is based on many components from a VW Beetle including chassis and engine, Very recently there has been a UK built 917 replica that uses the flat 6 from the 911.

Gallery

Video Games Appearance

• Need for Speed: Porsche Unleashed (Sony Playstation 1, 2/29/00 American release)
• Le Mans 24 (video arcade, 1997)

References

• 1976 -- The Fabulous Porsche 917 (1st edition) by P Hinsdale (ISBN 0-87799-052-2)
• 1986 -- PORSCHE 917 SUPER PROFILE by J Allen (ISBN 0-85429-605-0)
• 1987 -- PORSCHE 917 THE ULTIMATE WEAPON by I Bamsey (ISBN 0-85429-605-0)
• 1987 -- Porsche 917, Kimberleys Sportscar Guide by Michael Cotton (ISBN 0-946132-91-7)
• 1999 -- Porsche 917, the Winning Formula by Peter Morgan (ISBN 1-85960-633-4)
• 2000 -- Porsche 917, Unique Motor Books (ISBN 1-84155-297-6)

External Links

• Porsche Celebrates 40th Anniversary of Porsche 917
• Porsche 917 - Carsguide Car of the Week Carsguide Historical article