Porsche 917

Porsche
Helmut Kelleners in 1970 at the ADAC 1000 km race on the Nürburgring
917
Production period:	1968-1973
Class :	race car
Body versions :	Coupé , Spyder
Engines:	Petrol engines : 4.5–5.4 liters (383–810 kW)
Length:	3960-4780 mm
Width:	1880-2216 mm
Height:	920-1155 mm
Wheelbase :	2300-2500 mm
Empty weight :	730-909 kg
successor	Porsche 956

The Porsche 917 is a racing car from the German car manufacturer Porsche . It was presented at the Geneva Motor Show in 1969 .

The 917 was powered by an air-cooled twelve-cylinder mid- engine. The first engines had an output of 383 kW (520 hp) at 8000 rpm in 1969 with a displacement of 4.5 liters. In 1973 the engines were fitted with turbochargers and had an output of 810 kW (1100 hp) at 7800 rpm. The racing car was produced in the different body styles of the short-tail coupé, long-tail coupé and Spyder.

It was one of the most successful racing sports cars of the 1970s, and its importance for Porsche lies in the fact that it had achieved several overall victories in sports car races for the first time in what was then the largest displacement class. With the 917, Porsche achieved overall victory in the Le Mans 24-hour race for the first time in 1970 .

prehistory

The Porsche 917 took advantage of a loophole in the regulations, which should temporarily allow the use of already existing high-displacement sports cars, mostly from British small-series manufacturers, such as the Lola T70 with an American V8 engine. As in Formula 1 , only three-liter sports prototypes were to be used in the sports car world championship , but these were expensive and rare. In 1968, the international motorsport authority FIA raised the engine capacity limit from three to five liters and reduced the minimum number of units required for homologation for these large-volume sports cars from 50 to 25.

Porsche KG, which in 1962 had discontinued its Formula 1 involvement, which had just had its first successes, for cost reasons, took advantage of this opportunity to build a large-capacity racing car with reasonable effort and began developing the Porsche 917. The incentive was that Porsche had not yet won an overall sports car championship in its racing car history. Compared to the competition, the racing cars used up until then mostly had smaller and less powerful engines that were not powerful enough to achieve an overall victory.

development

Comparison of the original long and short tail on the Porsche 917

In 1968, the development of a coupé began on the basis of the Porsche 908 with a three-liter eight-cylinder engine and 258 kW (350 hp) . The designer of the Porsche 917 was Hans Mezger .

In March 1969, Porsche presented the 917 to the surprise of the experts at the Geneva Motor Show - and at the end of April 1969 the 25 copies required by the regulations were in the factory yard in Zuffenhausen , which allegedly required wooden brake blocks and similar improvisations. Because of the original paintwork, the car was nicknamed "White Giant".

With the 917, Porsche took a major economic risk, as the development of a series racing car was very expensive and sales success to private customers and racing teams was not guaranteed. The development was significantly supported by the then head of the Porsche development department, Ferdinand Piëch . Piëch later called the vehicle "the riskiest car of his life".

Ferrari was surprised by Porsche because the company specialized more in the production of prototypes and did not expect another manufacturer to undertake costly racing car development. In previous racing seasons it had become apparent that racing cars with large-capacity engines always dominated the championships. To achieve overall victory in the sports car world championship against the Porsche 917 with a three-liter prototype was very difficult for Ferrari. Ferrari was therefore forced to develop a comparable racing car, the Ferrari 512S , in a short time , and built it in the prescribed number. This was not used until 1970, when the Porsche 917 had already been tested in racing for a year.

Models

Porsche 917

Year of manufacture 1969

The Porsche 917 in its second race. David Piper and Frank Gardner drove the car in the 1000 km race at the Nürburgring in 1969.

body

By participating in small racing classes, Porsche had gained a great deal of experience in the lightweight construction of racing cars in the years up to 1969, which was implemented in the 917. The body was made of fiberglass-reinforced synthetic resin and was firmly attached to the frame. The engine was covered by a transparent hood made of polymethyl methacrylate (PMMA) with integrated air slots, as in the Porsche 908 Coupé. Since the synthetic resin skin was only about 1.2 millimeters thick, the doors and the bonnet were reinforced with aluminum tubes. The front window was made of laminated glass , the door windows were made of PMMA ("Plexiglas").

In order to be able to use the racing car successfully on different racetracks, two aerodynamically different body variants of the 917 were developed. The short tail version was designed for winding roads where high contact pressure was required for fast cornering. The long-tail version was better for racetracks with long straights where high top speeds had to be achieved. Each 917 could be brought into the other shape ( short or long tail ) relatively easily by attaching or removing the long tail fairing .

Movable flaps were originally mounted at the rear of the 917, which should bring more contact pressure to the relieved rear wheel when cornering. They were controlled via a linkage connected to the wheel suspension.

The elongated rear end, which was supposed to enable a high top speed, especially in Le Mans , initially proved to be very problematic in terms of grip. During test and training drives, the long-tail 917 reached speeds of almost 400 km / h on the Hunaudiéres Straight, which is now interrupted by two chicanes. The vehicles lay so restless on the track that they were almost impossible to drive and the Porsche works drivers preferred the Porsche 908 to the new 917 in races.

After movable wings were banned by the FIA ​​in mid-1969 because of serious accidents in Formula 1, the upper rear area was changed for the last races of the season. The bonnet rose to the top and now had a tear-off edge over the entire width. This version anticipated the shape of the 1970 variant.

engine and gears

The Porsche 917 was powered by a newly developed twelve-cylinder engine with a displacement of 4.5 liters , which, as a V-engine with a cylinder bank angle of 180 °, had six crank pins on the crankshaft . In the boxer engines otherwise used by Porsche , all connecting rods have their own crank pins, each offset by 180 ° on the crankshaft; so twelve would have been necessary, which would have increased the length and weight considerably. A special feature was the central output via a gear wheel located in the middle in the most favorable vibration range of the crankshaft, which transmitted the power to the drive shaft. This central gear wheel also drove the four camshafts via five gear wheels per cylinder row. The crankcase, which was split vertically in the middle, was cast from a magnesium alloy ( electron ); the cylinders with chrome-plated running surfaces and the pistons were made of an aluminum alloy , the connecting rods of titanium . The combustion chambers each had two spark plugs with double platinum electrodes. The 12-volt system was fed by a three-phase alternator .

The engine initially developed 383 kW (520 hp) at 8000 rpm and could deliver a maximum torque of 460 Nm at 6800 rpm.

The air cooling that was typical for Porsche at the time remained , with the 917 and the eight-cylinder racing engine type 771 with a horizontally positioned fan wheel that was driven by an intermediate shaft mounted in the crankcase via a pair of bevel gears. At 8400 rpm, this fan delivered 2400 liters of air per second and required 17 hp or around 3 percent of the engine output. "You can't lose air on the way," Ferdinand Piëch explained the decision. Since the two sports car models 911 and 912 built by Porsche at the time also had air-cooled engines, a racing car with an air-cooled engine should demonstrate the performance potential of this technology and be used for marketing purposes. The grandson of the company founder and later VW boss worked as a designer at Porsche KG in Stuttgart-Zuffenhausen and was the driving force behind the investment.

The engine had dual ignition with dual ignition distributors located in the front left and rear right in the crankcase. A twelve-piston injection system with nylon injection lines was newly developed for the 917. A pressure pump and six suction pumps for the dry sump lubrication supplied the oil circuit, which was thermostatically controlled and ran over the oil cooler when the oil temperature exceeded 90 ° C.

This 4.5-liter engine was further developed and in the next version delivered an output of 411 kW (560 hp) at 8300 rpm with the same displacement. The torque was also increased and had a maximum of 490 Nm at 6800 rpm.

The gearbox and the motor formed a unit that was suspended from the frame by elastic bearings. Depending on the race track, it was used with four or five gears; the forward gears were synchronized. The locking value of the differential could be varied, but was mostly 75%. The drive shafts had two universal joints and length compensation.

Year of manufacture 1970

Fan wheel of a Porsche 917

Porsche was not satisfied with the driving behavior of the 917 in the 1969 racing season. Despite some changes, the car was very restless on the road at high speeds of over 300 km / h and was difficult to control for the pilots. Based on this experience, the rear of the 917 was redesigned for the 1970 racing season, especially in collaboration with John Wyer’s Gulf team .

As a result, two new rear variants were created: a revised long tail and a now wedge-shaped short tail, which led to better handling of the car. These short-tail racing cars were also called the 917 K. The transparent Plexidur cover was dispensed with in both new body versions, so that the intake funnel and the horizontally positioned fan wheel were now exposed. The body was also around 96 mm wider, so that wider tire formats could be fitted.

Each of the 25 original chassis (excluding those that were destroyed and / or cannibalized) have been converted into the 917 K. The fairing behind the rear wheels was removed and a new hood was installed. This now had two bumps that rose backwards and each had a large tear-off edge. Sometimes a wing element was attached between the humps and only small spoiler edges were used.

In contrast, new chassis were built for the two 917 LHs. Their body had been completely redesigned compared to 1969 and now proved to be much more stable. The 917 LH could no longer be converted to short-tail versions. They were only used in Le Mans.

The engine has undergone further changes. Mainly the displacement was increased from 4.5 to 5.0 liters so that it developed 442 kW (600 hp) at 8400 rpm. To reduce the risk of gear shifting in the race, a four-speed gearbox was used instead of a five-speed gearbox.

Year of manufacture 1971

The 917 long-tail coupé was at the end of the Mulsanne straight in 1971 with a top speed of 386 km / h.

The aerodynamics have been further improved - especially at the front. These measures were necessary because Ferrari's cars were now facing greater competition. Two so-called “shark fins” at the rear of the 917 K used in Le Mans improved directional stability on the fast sections of the route. This aerodynamic improvement had already been successfully tested in the race in Monza. Porsche also revised the body of the 917 LH again in cooperation with the French company SERA and a third 917 LH was built.

Work was also continued on weight reduction. As a result, Porsche used a magnesium tubular frame instead of the aluminum tubular space frame in some racing cars, such as the winning car in the Le Mans 24-hour race. This new tubular space frame saved a few more kilograms of weight compared to the aluminum version (approx. A third compared to aluminum), but would have been much more dangerous even in a fire accident due to the easier flammability of magnesium.

The 917 engine now developed 442 kW (600 hp) from a displacement of 4.9 liters in all racing cars used. There was a further expansion stage with " Nikasil " cylinder running surfaces (a coating with nickel - silicon carbide developed by Mahle ) and the maximum permitted displacement of 4.99 liters. This engine developed 463 kW (630 hp) at 8300 rpm and thus represented the final stage of the conventional 917 naturally aspirated engines.

As early as 1970, Porsche was also active in the European Interseries with its 917 , where open Group 7 cars were used. First, a 917 short-tail coupe was used successfully. In the following year, 1971, Porsche developed an open Spyder version based on the Porsche 917 PA, the Porsche 917 Spyder , which was specially designed for the Interseries. In Group 7 there were no minimum weight specifications, so that the newly developed car only weighed 730 kg. The engine used was the 442 kW (600 hp) 4.9 liter unit.

With this car, driver Leo Kinnunen succeeded in winning the Interseries in 1971 and claiming another title for Porsche. From 1972 the Porsche 917 Spyder was replaced by the Porsche 917/10 in the Interseries.

Porsche 917/20

Porsche 917/20 "Pig" from 1971

In 1971, a modified version was used in Le Mans alongside the tried and tested Porsche 917. This car was a combination of a short and long tail version with revised aerodynamics and a particularly wide body that Porsche had developed in collaboration with the French company SERA. The engine of the 917/20 remained unchanged and, as in the other Porsche 917 racing cars, developed 442 kW (600 hp) at 8400 rpm.

This car was very conspicuous because of its pink paintwork and the recorded portions of meat that Porsche designer Anatole Lapine came up with and was therefore nicknamed “Die Sau”, “Big Berta” or “Truffle hunter” (see photo on the right). In the race, the car that had won the preparatory race fell out of fifth position due to an accident.

The car remained a one-off.

Porsche 917/10

A Porsche 917 PA that was used at CanAm

At the end of the 1971 season, the special regulation for five-liter sports cars expired. From 1972, five-liter sports cars such as the Porsche 917, Ferrari 512 , Lola T70 or Ford GT40 were no longer approved for the FIA ​​branded sports car world championship. As a result, Porsche decided to contest further races with the 917 in the so-called CanAm championship in the USA .

Jo Siffert took part in this series as early as 1969 with an open version of the 917, the Porsche 917 PA . The addition PA stands for Porsche-Audi and refers to the joint importer of the two brands in North America, under whose name the Spyder was registered. At that time, however, the 4.5-liter twelve-cylinder engine proved to be inferior to the larger-capacity racing cars with V8 engines from Chevrolet, which later had a displacement of up to 9 liters and 589 kW (800 hp).

In 1971 and 1972, the 917 PA with a 5-liter twelve-cylinder engine continued to be used in the CanAm.

Year of manufacture 1971

Porsche 917/16 Spyder with 16-cylinder engine, the development of which was discontinued in favor of the 917/10

In contrast to the 917, which had coupé bodies in the European sports car world championship , the cars for the CanAm championship were designed with a Spyder body.

The large rear wing and the specially shaped, shovel-like front section were trimmed for maximum downforce. This increased the air resistance , so that “only” a top speed of 343 km / h was measured.

At the beginning of the CanAm racing season, the Porsche 917/10 was still used with a 5-liter twelve-cylinder engine without a turbocharger. In all races the car was driven by Jo Siffert, whose best result was a second place in two races. The 917/10 was already superior to the 917 PA, but compared to the more powerful McLaren and Lola racing cars, there was still a lack of engine power in order to achieve victories.

In his search for more engine power, Ferdinand Piëch preferred a 16-cylinder engine, as had already been designed by his grandfather Ferdinand Porsche for the Auto-Union - Silver Arrows . Three engines were built, but they did not prove to be stable for racing. The 16-cylinder engine had a displacement of 6643 cc, 551 kW (750 hp) at 8000 rpm and a maximum torque of 735 Nm at 6500 rpm. The 16-cylinder engine was installed and tested in the so-called Porsche 917/16 Spyder . Since the engine charging with compressor had already proven itself earlier and, together with the proven and compact twelve-cylinder engine block, delivered even more power, the further development of the 16-cylinder engine was discontinued.

Porsche 917/10 with 12-cylinder engine and bi-turbocharging

That is why the previous naturally aspirated engine (engine type 912 with 4.5 liter displacement) was equipped with two turbochargers (bi-turbo) by Porsche factory engineers in 1971 . The compression ratio was reduced from 10.5: 1 to 6.5: 1. Two Eberspächer turbochargers with paddle wheels reaching 90,000 rpm ensured a significant increase in performance.

As is customary with all Porsche racing and production vehicles, the engine was still air-cooled. The cooling air throughput had to be increased accordingly. The outlet valves, whose operating temperature was between 1000 ° C and 1100 ° C, were made of titanium.

Roger Penske's American team , along with driver and engineer Mark Donohue, played a key role in the tests.

With a boost pressure of 1.3 bar, the engine output of the 4.5 liter engine could be increased from 383 kW (520 PS) to 626 kW (850 PS) at a speed of 8000 / min, which is roughly on par with the competition their large American naturally aspirated V8 engines.

However, problems arose with the more difficult deployment and responsiveness of the turbo power. For this reason, control valves were installed with which the boost pressure in the engine could be limited, which made the sudden increase in power manageable. This solution was later applied to the 917/30 Spyder. You could change the maximum boost pressure from the cockpit using a special electronic control at the push of a button. An addition of 0.1 bar meant an increase in output of 37 kW (50 PS).

This so-called Porsche 917/10 TC (TC stands for turbo-charged, English T urbo C harged ) was only used in races at the CanAm in 1972.

Year of construction 1972

In 1972 the displacement was increased to five liters, which means that the engine now developed 736 kW (1000 hp). The two versions of the Porsche 917/10 TC, which were equipped with a large rear wing to increase downforce, prevailed against the previously dominant competition from McLaren and Porsche won the CanAm title.

The 917/10 TC was replaced in 1973 by the Porsche 917/30 Spyder.

Porsche 917/30

Porsche 917-30 CanAm Spyder, cockpit

The Porsche 917/30 was the last and most powerful variant of the Porsche 917 racing car, which was developed for the CanAm championship in North America. The 917/10 was developed as early as 1971, with Porsche using turbo engine technology in a racing car for the first time. The experience gained with the 917/10 flowed significantly into the development of the 917/30.

Year of construction 1973

Porsche 917/30 Spyder in the Porsche Museum Stuttgart

The vehicle was further improved with the participation of Mark Donohue and engineer Helmut Flegl. The focus was particularly on the engine, which was enlarged to 5.4 liters and delivered 810 kW (1100 hp) at 7800 rpm. The maximum torque was 1098 Nm at 6400 rpm. On the test bench, the engine even developed 1156 kW (1570 hp) with a boost pressure of 2.24 bar. This engine in the 917/30 Spyder is still considered to be the most powerful machine ever used in a circuit race.

Thanks to this performance, the car, weighing just 845 kilograms, could be accelerated from zero to 100 km / h in 2.4 seconds (in 1st gear) and from zero to 200 km / h in 5.6 seconds. The speed of 300 km / h was reached in just 11.3 seconds. The car had a 4-speed gearbox and the final drive had no differential, but a rigid through drive.

Various tests led to the conclusion that this car can reach a top speed of over 400 km / h. Thanks to the wheelbase lengthened from 2300 mm to 2500 mm, the racing car had a more stable roadholding than its predecessor models. The stated maximum speed ranges from 382 km / h to 413.6 km / h. The fuel consumption was between 76 and 97 liters per 100 kilometers, which is why two tanks (to the right and left of the driver's seat) with a total capacity of 400 liters were used.

The 1100 hp Porsche 917/30 Spyder at a demonstration at the Nürburgring (1981)

Year of construction 1974

The tank capacity was up to now 400 liters due to the enormous gasoline consumption. Due to a change in the regulations, consumption was limited from 1974, among other things for safety reasons, due to the oil crisis and probably also for reasons of competition. With these new restrictions, the 917/30 could no longer utilize their full capabilities and were therefore only used once in a race.

The CanAm series was discontinued in mid-1974 as sponsors withdrew due to economic problems. This meant the final end of the 917/30 for racing use.

Year of construction 1975

With an aerodynamically improved version, record drives were carried out on the Talladega Superspeedway in Alabama. The Porsche 917/30, with Mark Donohue at the wheel, set a new lap record with an average speed of 375.918 km / h. The top speed achieved was 413.6 km / h. The record still holds, as the NASCAR touring cars with V8 naturally aspirated engines could achieve an average speed of 344 km / h. The ChampCars achieved speeds of up to 388 km / h in training in Fontana (California) , but never drove in Talladega.

Racing history

1969 - The beginning

In 1969, the Porsche 917 was initially not yet aerodynamically tuned, so that it was very difficult to control. This is why the works drivers refused to drive the 917 in its second outing in the sports car world championship, the 1000-kilometer race on the uneven Nordschleife of the Nürburgring . Since Porsche absolutely wanted to sell the models that had already been produced to private drivers and had to show some success, the Briton David Piper and the Australian Frank Gardner were hired to drive the 917 to eighth place. With a fastest lap of 8: 37.8 minutes, the car was 37.6 seconds slower in practice than the Porsche 908 of Joseph Siffert and Brian Redman, which started from first place . Piper complained that the rear of the 917 lost contact pressure with increasing speed and that it needed almost the entire width of the street in fast corners. Another source reported a tendency for the car to "become 'lighter' at the front in certain driving conditions". Three weeks before the Nürburgring race, the 917 had failed after the first lap with valve damage during the 1000 km of Spa . The car was driven by Gerhard Mitter and Udo Schütz , who, however, only sat at the wheel during practice, as it was not used in the race due to its early retirement.

At the 24 Hours of Le Mans in 1969 the 917 entered the race as favorites, but John Woolfe and his customer 917 had a fatal accident on the first lap . The other 917s led the race for a long time, but ultimately couldn't fight for overall victory due to various technical problems. This won the equipped also with 5-liter engine Ford GT40 of Jacky Ickx and Jackie Oliver with a narrow lead of 50 meters in front of the three-liter 908 of Hans Herrmann and Gérard Larrousse .

Still in the same year celebrated Jo Siffert and Kurt Ahrens at the 1000 km race at Zeltweg its first overall victory in the 917 short-tail coupe version.

The Porsche 917 PA with a Spyder body was developed for use in the CanAm. Jo Siffert drove this racing car in five CanAm races. However, the engine power was not enough for a victory over the McLaren and Lola with Chevrolet V8 engines.

1970 - First overall Le Mans victory for Porsche

Porsche 917 (chassis no. 917-001) in the Porsche Museum Stuttgart-Zuffenhausen. The car was subsequently given the look of the Le Mans winning vehicle from 1970. The original winning car (chassis no. 917-023) is in a private collection.

On June 14, 1970 , Porsche achieved the brand's greatest success to date in the Le Mans 24-hour race . The red and white 917 K of Hans Herrmann and Richard Attwood with the starting number 23, registered by Porsche Salzburg, crossed the finish line as the winner with 343 laps. This was the first overall Le Mans victory for Porsche. The 917 long-tail vehicle from Martini-Racing, painted in a kind of blue-green psychedelic design, which is commonly referred to as "hippie" and driven by Gérard Larrousse and Willi Kauhsen , finished second overall with 338 laps.

In addition to the Le Mans 24-hour race, the Porsche 917 was also very successful in the other races for the World Sports Car Championship. So were the 24-hour race at Daytona , the 1000 km race from Brands Hatch, the 1000 km race from Monza , the 1000 km race from Spa-Francorchamps , the 6-hour race from Watkins Glen and the overall victory in the 1000 km race at the Österreichring.
Only in the 12-hour race in Sebring in March did a 917 K, driven by Pedro Rodríguez and Leo Kinnunen, only achieve fourth place. At the Targa Florio and the 1000 km race at the Nürburgring , no 917 was used in the race. Thanks to this series of successes, Porsche was able to win the World Sports Car Championship again.

In the CanAm, the 917 KH were used in only one race, that in Watkins Glen, and they also competed there in the World Sports Car Championship. The racing cars with the 4.9-liter and 5-liter 12-cylinder engines were very successful and occupied positions two to four, six and seven behind a McLaren M8D .

In 1970, the Interserie was launched in Europe as a counterpart to the North American CanAm. Porsche fielded the 917 KH there together with some racing teams in Group 7 and was able to win the first title with driver Jürgen Neuhaus.

1971 - The second overall victory in the World Sports Car Championship

Winner car of the 24 Hours of Le Mans 1971

At Le Mans , Porsche repeated its success in the 24-hour race from the previous year, but for the third time it was not enough for the long-tail versions with speeds of up to 396 km / h in practice. This went to the white Martini Porsche 917 K owned by Helmut Marko and Gijs van Lennep with the number 22. With an average speed of 222 km / h, the winning team also set a new course record.

With the exception of the 1000 km race at Brands Hatch, the 1000 km race at the Nürburgring and the 6-hour race at Watkins Glen, Porsche was able to win every other sports car world championship. As in the previous year, instead of a Porsche 917, the Porsche 908/03 was used in the Targa Florio. Porsche thus won the constructors' title of the world championship for the second time after 1970.

Porsche developed the Porsche 917/10 after the first experiences gained in the CanAm in 1969 and 1970. This car, equipped with a 5-liter, 12-cylinder naturally aspirated engine, driven by Jo Siffert, could not prevail against the racing cars with Chevrolet engines. The 917 PA, which was first tested in 1969, was continued to be used by a private team with a new 5-liter engine.

In order to remain competitive in the Interseries, Porsche developed an open version of the 917 for a customer. This Porsche 917 Spyder was approx. 100 kg lighter than the coupé version of the 917 and successfully prevailed over the competition with Leo Kinnunen .

1972 - First success at CanAm

Porsche 917/10 TC that won the CanAm championship

Since the Porsche 917 was no longer allowed to take part in the sports car world championship from 1972 due to the end of the special regulation for five-liter sports cars, Porsche looked for another field of activity. In the popular Canadian-American CanAm racing series, Porsche found a new field of application for the 917. Since the Porsche 917 PA and Porsche 917/10, which were originally equipped with naturally aspirated engines, were inferior to the competition there, the more powerful 917/10 TC was developed with the 1972 George Follmer became CanAm Champion with Penske Racing .

In the 1972 interseries season, the Finnish AAW Racing Team now used the 917/10 with a 5.4-liter, twelve-cylinder naturally aspirated engine instead of the 917 Spyder. Later in the season this was in turn replaced by the more powerful Porsche 917/10 TC. With the help of these superior racing cars, Leo Kinnunen was able to win the Interseries for the second time in a row.

1973 - The 917 asserts itself again in the CanAm

Porsche 917/30, winner of the 1973 CanAm championship

In 1973 Porsche and Penske Racing won the CanAm championship again and more clearly than in the previous year, this time with the driver Mark Donohue in a Porsche 917/30. In addition to the 917/30, the Porsche 917/10 TC were also very successful, with pilots finishing second to fourth in the drivers' championship.

In the 1973 Interserie, the Porsche 917/10 and 917/10 TC dominated the races at will. In every race, a Porsche was the first car to cross the finish line. The season was ultimately won by Leo Kinnunen with Team MSC Stuttgart / Racing Team AAW, who prevailed over the other drivers with four wins.

The two drivers Willi Kauhsen and Georg Loos , who each also drove a 917/10 TC, were also very successful.

1974 - The end of the CanAm

A Porsche 917/10 TC as used in the Interseries

With the end of the CanAm due to the economic and oil crisis, the successful era of the 917 also ended. The 917/30 was therefore only used once in the fourth race of the CanAm season, next to a 917/10 that was in customer hands. The CanAm was prematurely discontinued in August after the 5th race and only revived three years later in 1977. Due to new regulations, the 917 could no longer be used competitively in the CanAm.

As in the 1973 CanAm, the Porsche 917/30 with the turbocharged twelve-cylinder engine was used in the 1974 Interseries. However, the interseries version had a smaller five-liter engine instead of a 5.4-liter unit. This car was used by the Martini Racing Team with driver Herbert Müller , who was also able to confidently win the drivers' title.

1975 - The last appearances in the Interseries

The Porsche 917 was only used in the Interseries in 1975. The 917/30 had its last successful race at the Wiesbaden Prize at the Hockenheimring , where Herbert Müller won the race. The Porsche 917/10 with a 5.6-liter, twelve-cylinder naturally aspirated engine and the 917/10 TC with a turbocharged 4.5-liter, twelve-cylinder engine were used throughout the season. Here triumphed Tim taverns in Zandvoort , at the Nurburgring and the price of Baden-Wuerttemberg and Hesse at Hockenheim.

1981 - Revival in the sports car world championship

The last known sports use of a Porsche 917 outside of historical racing took place in 1981. The Cologne racing team Kremer had collected enough vehicle components over the years to build a complete Porsche 917 from them. It was a short-tail coupé that had vertical stabilizing fins in the rear area with a one-piece wing in between - similar to the design that was last used on the CanAm Spyders. The car was equipped with a 4.5 liter naturally aspirated engine and had the official designation Kremer-Porsche 917 K81. The vehicle was used in two races: At the 24 Hours of Le Mans 1981, the drivers Bob Wollek , Guy Chasseuil and Xavier Lapeyre retired in the 18th hour after an engine suspension broke. During the 1000 kilometers of Brands Hatch 1981, Bob Wollek also had to park the Kremer Porsche 917 K81 early. The reason was a defect in the wheel suspension.

The results from 1969 to 1975

1969

1970

1971

1972

1973

1974

1975

The Porsche 917 in the film

Porsche 917 with Gulf Racing livery

US director Lee H. Katzin set a monument in 1971 with the film Le Mans and Steve McQueen in the leading role of the great sports cars Porsche 917 and Ferrari 512. The film was produced and financed by McQueen. The secret star of the film and the shooting, however, was an open-top Porsche 908/2 from Herbert Linge and Jonathan Williams , which competed in the 24-hour race in 1970 - albeit out of competition - and despite the clunky film cameras and frequent stops when the ninth car crossed the finish line. The 917 also appears in a supporting role in the feature film The Great Beetle in the Monte Carlo Rally from the Herbie series. In the film he is driven by Bruno von Stickle - played by Eric Braeden - and is the toughest competitor of "Herbie" in the eponymous Monte Carlo Rally until the end , but finally has to admit defeat. The film is not historically accurate - the Porsche 917 was never officially used in the Monte Carlo Rally.

Porsche 917 street legal

Porsche 917K (year of construction 1970) approved for public road traffic with license plate of the US state California .

Some examples of the Porsche 917 were also approved for use on public roads.

The car with chassis number 917-030, built in 1971, was rebuilt in 1974 at the Porsche factory for Count Gregorio Rossi di Montelera, one of the owners of the spirits manufacturer Martini & Rossi . Porsche tried unsuccessfully to get this 917 street legal within Europe. Ultimately, Rossi received approval and the corresponding license plates from the US state of Alabama.

The innkeeper at the time, Joachim Großmann, bought another car to convert it for road approval. It was the 1969 built 917 KH with the chassis number 917-021, which the drivers Gijs van Lennep and Hans Laine drove in the 1970 sports car world championship in the races in Monza and Spa in eleventh and fifth place. The racing car of the AAW Racing Team of Gijs van Lennep and David Piper , equipped with a 4.5-liter 12-cylinder engine, was used in the Le Mans 24-hour races . The car retired on the ninth lap after an accident with David Piper at the wheel and was not used in races after that. Some parts were used for the 917 Spyder that Leo Kinnunen drove in the Interseries . The remainder went to Karlsruhe, where Großmann bought the car in 1976 for 20,000 DM and then rebuilt it. Before the district office of Calw granted Großmann a road approval for the former racing car on June 3, 1977 (official registration number CW-K 917), various retrofits were necessary, for example the installation of a hazard warning system, a handbrake and a window heater. A modified exhaust system also had to be installed in order to dampen the engine noise in accordance with legal requirements. The vehicle was later converted back into a racing car and is now owned by Juan Barazi .

Technical specifications

The Porsche 917 was produced and used from 1968 to 1973 in the following versions:

Porsche 917:	917 LH 1 (1969)	917 KH 2 (1969)	917 LH (1970)	917 KH (1970)	917 LH (1971)	917 KH (1971)	917 Spyder (1971)	917/20	917/10 TC 3 (1971)	917/10 TC (1972)	917/30
Engine:	Twelve cylinders - V-engine (180 ° bank angle ), four-stroke								ditto with turbocharger
Displacement:	4494 cc		4999 cc		4999 cc		4999 cc		4494 cc	4999 cc	5374 cc
Bore × stroke:	85 × 66 mm		86.8 x 70.4 mm						85 × 66 mm	86.8 x 70.4 mm	90 x 70.4 mm
Performance at 1 / min:	383 kW (520 hp) 8000		442 kW (600 hp) 8400		463 kW (630 hp) 8300		442 kW (600 hp) 8400		626 kW (850 PS) 8000	736 kW (1000 hp) 7800	810 kW (1100 hp) 7800
Max. Torque at 1 / min:	460 Nm 6800		549 Nm 6500		588 Nm 6500		549 Nm 6500		834 Nm 6600	981 Nm 6400	1098 Nm 6400
Compression:	10.5: 1		10.3: 1						6.5: 1
Valve control:	two overhead camshafts per cylinder bank, driven by spur gears
Cooling:	Air cooling (fan)
Transmission:	4- or 5-speed gearbox, limited slip differential, rear-wheel drive								4-speed gearbox, limited-slip differential, 917/30: rigid through drive, rear-wheel drive, with 917/30 additionally: three-plate clutch
Brakes:	internally ventilated disc brakes, with the 917/30 additionally: 4-piston brake caliper
Wheel suspension v + h:	Double wishbones with torsional anti-roll bar
Suspension v + h:	Titanium coil springs with gas pressure shock absorbers
Body:	Glass fiber reinforced synthetic resin body, firmly connected to the frame, doors and bonnet reinforced with aluminum tubes		Aluminum space frame with plastic body						Aluminum tubular space frame with plastic body on 917/30: Magnesium ( electron ) tubular space frame with plastic body
Track width front / rear:	1488/1457 mm		1564/1584 mm	1564/1533 mm	1564/1584 mm	1564/1533 mm	1564/1584 mm	1526/1584 mm	1620/1638 mm		1670/1564 mm
Wheelbase :	2300 mm								2316 mm		2500 mm
Tires rim:	VA: 4.75 / 11.30-15 on 9J × 15 HA: 6.00 / 13.50-15 on 12J × 15		VA: 4.75 / 11.30J × 12 HA: 6.00 / 13.50J × 17	VA: 10.5J x 15; 12J x 15 HA: 15J x 15; 17J × 15	VA: 4.75 / 11.30J × 12 HA: 6.00 / 13.50J × 17	VA: 4.75 / 11.30J × 12 HA: 6.00 / 13.50J × 17	VA: 10.5J x 15; 12J x 15 HA: 15J x 15; 17J × 15	VA: 10.5J × 15 HA: 17J × 15	VA: 12J x 15 HA: 17J x 15; 19J × 15		Front : 12Jx15 rear: 19Jx15
Length:  Width:  Height:	4780 × 1880 × 920 mm	4290 × 1880 × 920 mm	4780 × 1975 × 920 mm	4140 × 1975 × 920 mm	4780 × 1975 × 920 mm	4140 × 1975 × 920 mm	4100 ×? ×? mm	3960 × 2216 × 926 mm	4385 × 2100 × 1180 mm		4562 × 2085 × 1155 mm
Empty weight :	830 kg	800 kg	800 kg		830 kg		730 kg	909 kg	750 kg		800 kg
Top speed:	approx. 340 km / h	approx. 320 km / h	386 km / h	approx. 340 km / h	395 km / h	approx. 360 km / h	approx. 330 km / h	approx. 360 km / h	343 km / h	approx. 360 km / h	385 km / h / 409 km / h (low downforce)
Acceleration 0 - 100 km / h:											2.1 s 4
Acceleration 0 - 200 km / h:											5.3 s
Acceleration 0 - 300 km / h:											11.3 s

¹ LH stands for long tail
² KH stands for short tail
³ TC stands for turbocharging. T urbo C harged
⁴ According to the Guinness Book of Records, the best value that a racing car has ever achieved.

Technical data of the prototype 917/16 Spyder

The Porsche 917/16 was tested with different engines. The data listed here comes from the version that had proven to be reliable during test drives. The prototype can be viewed today in the Porsche Museum in Stuttgart.

View of the 6.6-liter 16-cylinder engine of the 917/16 Spyder prototype

Porsche 917:	917/16 Spyder
Engine:	16-cylinder V-engine (180 °), four-stroke
Displacement:	6643 cc
Bore × stroke:	86 x 70.4 mm
Performance at 1 / min:	551 kW (750 PS) 8000
Max. Torque at 1 / min:	735 Nm 6500
Compression:
Valve control:	two overhead camshafts per cylinder bank with steering wheel drive
Cooling:	Air cooling (fan)
Transmission:	5-speed gearbox, limited slip differential, rear-wheel drive
Brakes:	internally ventilated disc brakes
Front suspension:	Double wishbones with torsional anti-roll bar
Rear suspension:	Double wishbones with torsional anti-roll bar
Front suspension:	Titanium coil spring with gas pressure shock absorber per wheel
Rear suspension:	Titanium coil spring with gas pressure shock absorber per wheel
Body:	Aluminum space frame with plastic body
Track width front / rear:	1526/1533 mm
Wheelbase :	2570 mm
Tires rim:	VA: 10.5J x 15; 12J x 15 HA: 15J x 15; 17J × 15
Dimensions L × W × H:	3905 ×? ×? mm
Empty weight :	775 kg
Top speed:	approx. 360 km / h

Trivia

In January 2010, Porsche presented the 918 RSR, a concept vehicle for a hybrid racing car. In memory of the winning car of the 24 Hours of Le Mans in 1971, the starting number 22 was affixed to the front hood and doors. The color scheme of the prototype with an orange central stripe from bow to stern is based on the Porsche 917, which John Wyer’s team used in the brand world championship in 1970 and 1971 with main sponsor Gulf.

literature

• Peter Schneider: Type compass Porsche: Racing and racing sports cars since 1948. Motorbuch-Verlag, Stuttgart 2003, ISBN 3-613-02300-8 .
• Thomas Födisch, Jost Neßhöver, Rainer Roßbach, Harold Schwarz: Porsche 917: The heroes, the victories, the myth. Verlag Reinhard Klein, Cologne 2006, ISBN 3-927458-26-0 .
• Walter Näher: Porsche 917. Archive and work directory 1968-1975. Delius Klasing-Verlag, Bielefeld 2009, ISBN 978-3-7688-2651-8 .
• Reynold Hézard: Porsche 917: A Success Story. Heel-Verlag, Königswinter 2009, ISBN 978-3-86852-085-9 .
• Glen Smale: Porsche 917. Motorbuch-Verlag, Stuttgart 2010, ISBN 978-3-613-03230-9 .
• Lothar Boschen, Jürgen Barth: The big book of Porsche types: All vehicles from 1948 to today. 2nd edition, Motorbuch-Verlag, Stuttgart 1994, ISBN 3-613-01284-7 .
• Stuart Gallaher: The fascination of Porsche. Parragon Books Ltd., Bath, ISBN 1-4054-8355-5 .

Web links

Commons : Porsche 917  - collection of pictures, videos and audio files

Porsche database

• Porsche 917 / 4.5 Kurzheck Coupé on Porsche.com ( Memento from June 5, 2009 in the Internet Archive )
• Porsche 917 / 4.5 Langheck Coupé on Porsche.com ( Memento from June 4, 2009 in the Internet Archive )
• Porsche 917 / 4.9 Langheck Coupé on Porsche.com ( Memento from May 10, 2009 in the Internet Archive )
• Porsche-Austria 917 / 4.5 Kurzheck Coupé on Porsche.com ( Memento from May 10, 2009 in the Internet Archive )
• Porsche-Gulf 917 / 4.9 Kurzheck Coupé on Porsche.com ( Memento from May 10, 2009 in the Internet Archive )
• Porsche 917/20 Coupé "Pig" on Porsche.com ( Memento from May 10, 2009 in the Internet Archive )
• Porsche 917 / 4.9 Spyder "Interserie" on Porsche.com ( Memento from May 10, 2009 in the Internet Archive )
• Porsche 917 / 5.0 Kurzheck Coupé "Magnesium" on Porsche.com ( Memento from May 10, 2009 in the Internet Archive )
• Porsche 917/16 Spyder on Porsche.com ( Memento from May 10, 2009 in the Internet Archive )
• Porsche 917/10 CanAm Spyder on Porsche.com ( Memento from May 10, 2009 in the Internet Archive )
• Porsche 917/30 CanAm Spyder on Porsche.com ( Memento from May 10, 2009 in the Internet Archive )

Fan pages and body registers on the Internet

• Last use of the 917/30 (English)
• Fan page for the Porsche 917 (English)
• Chassis numbers ( Memento from October 27, 2012 in the Internet Archive )
• Current chassis registry

Individual evidence

1. ↑ ^{a b} Dr. Ing.hc F. Porsche AG: 1969 Porsche 917 / 4.5 long-tail coupé, racing history / racing car ( Memento from June 4, 2009 in the Internet Archive ) at: www.porsche.com/germany/ . October 3, 2011
2. ↑ ^{a b c} one day's contemporary stories on Spiegel online:One day the Holy Grail with 1400 HP On: www.spiegel.de . April 2009
3. ↑ 40 years of the Porsche 917: White Giant and Can-Am Killer On: www.motorline.cc . September 14, 2010
4. ↑ ^{a b} Interview with Ferdinand Piëch ( memento from February 11, 2013 in the web archive archive.today ), Braunschweiger Zeitung, Salzgitter Zeitung, Wolfsburger Nachrichten, April 16, 2007.
5. ↑ Dr. Ing.hc F. Porsche AG: Press release: 40 years ago, Porsche won Le Mans for the first time ( memento from February 1, 2013 in the web archive archive.today ) on: porsche.com . June 11, 2010.
6. ↑ Sports car legend Porsche 917 in the driving report: Time travel in a 520 hp oldtimer On: www.auto-motor-und-sport.de . February 10, 2010, accessed April 19, 2012
7. ↑ Piëch's Cars - Visions of an Engineer: Piëch's Cars - Porsche 917, Audi Quattro, Bugatti Veyron, VW 1-liter car ( Memento from February 2, 2014 in the Internet Archive ) at: www.autozeitung.de . Retrieved April 20, 2012
8. ^ WDR5 ZeitZeichen, April 17, 1937: The birthday of the engineer and entrepreneur Ferdinand Piëch , broadcast on April 17, 2012.
9. ↑ ^{a b c d e f g h} Boschen / Barth: The great book of Porsche types. All vehicles from 1948 to today. Pp. 405-412.
10. ↑ ^{a b c} Stuart Gallaher: Fascination Porsche. P. 159.
11. ↑ ^{a b} Dr. Ing.hc F. Porsche AG: 1970 Porsche-Austria 917 / 4.5 Kurzheck Coupé, racing history / racing car ( Memento from May 10, 2009 in the Internet Archive ) at: www.porsche.com/germany/ . October 3, 2011
12. ↑ Dr. Ing.hc F. Porsche AG: 1970 Porsche-Gulf 917 / 4.9 Kurzheck Coupé, racing history / racing car ( Memento from May 10, 2009 in the Internet Archive ) at: www.porsche.com/germany/ . October 3, 2011
13. ↑ Dr. Ing.hc F. Porsche AG: 1970 Porsche 917 / 4.9 Langheck Coupé, racing history / racing cars ( Memento from May 10, 2009 in the Internet Archive ) at: www.porsche.com/germany/ . October 3, 2011.
14. ↑ ^{a b} Dr. Ing.hc F. Porsche AG: 1971 Porsche 917 / 5.0 Kurzheck Coupé "Magnesium", racing history / racing car ( Memento from May 10, 2009 in the Internet Archive ) at: www.porsche.com/germany/ . October 3, 2011.
15. ↑ ^{a b} Dr. Hc F. Porsche AG: 1971 Porsche 917 / 4.9 Spyder "Interserie", racing history / racing cars ( Memento from May 10, 2009 in the Internet Archive ) at: www.porsche.com/germany/ . October 3, 2011.
16. ↑ Dr. Ing. Hc F. Porsche AG: 1971 Porsche 917/20 Coupé "Sau", racing history / racing car ( Memento from May 10, 2009 in the Internet Archive ) at: www.porsche.com/germany/ . October 3, 2011
17. ↑ Dr. Ing.hc F. Porsche AG: 1970 Porsche 917/16 Spyder, racing history / racing cars ( Memento from May 10, 2009 in the Internet Archive ) at: www.porsche.com/germany/ . October 3, 2011
18. ↑ Evolution sports car. Turbocharging. ( Memento from November 19, 2014 in the archive.today web archive ) Porsche.com, October 24, 2014.
19. ↑ ^{a b} Dr. Ing.hc F. Porsche AG: 1972 Porsche 917/10 Spyder, racing history / racing cars ( Memento from May 10, 2009 in the Internet Archive ) at: www.porsche.com/germany/ . October 3, 2011
20. ↑ ^{a b} Dr. Ing.hc F. Porsche AG: 1973 Porsche 917/30 Spyder, racing history / racing cars ( Memento from May 10, 2009 in the Internet Archive ) at: www.porsche.com/germany/ . October 3, 2011
21. ↑ Auto Bild magazine, issue No. 21 from May 23, 2008
22. ↑ Classicscars - Internet site: Race results of the sports car world championship 1969. At: www.classicscars.com , accessed on December 2, 2011 . 
23. ↑ Behrndt / Födisch / Behrndt: ADAC 1000 km race . Heel Verlag, Königswinter 2008, ISBN 978-3-89880-903-0 , p. 68.
24. ↑ Auto, Motor und Sport Magazin, Issue No. 13 from 1969, p. 84.
25. ^ Auto, Motor und Sport Magazin, Issue No. 11 from 1969, p. 126.
26. ↑ Classicscars - Internet site: Race results of the sports car world championship 1969. At: www.classicscars.com , accessed on December 3, 2011 . 
27. ↑ Dr. Ing.hc F. Porsche AG: 1969 Porsche 917 / 4.5 Kurzheck Coupé, racing history / racing car ( Memento from June 5, 2009 in the Internet Archive ) at: www.porsche.com/germany/ . October 3, 2011
28. ↑ Oldtimer Markt , issue No. 6 from 2003, p. 8 ff.
29. ↑ Documentation on the history of the chassis number 917-023. On: 962.com , archived from the original on August 21, 2013 ; Retrieved January 6, 2012 . 
30. ↑ Documentation on the history of the chassis number 917-001. On: 962.com , archived from the original on July 7, 2012 ; Retrieved January 6, 2012 . 
31. ↑ Glen Smale: Porsche 917. pp. 485-487.
32. ^ Porsche drivers , issue no.1 from 2008
33. ↑ Reynold HEZARD: Porsche 917: a success story. Pp. 220-222.
34. ↑ ^{a b} Auto, Motor und Sport Magazin, issue No. 14 from 1977
35. ↑ RacingSportsCars - Website: Chassis 917-021 On: www.racingsportscars.com . October 11, 2011
36. ↑ itd - website: 917-Strasse. In: www.itd.net. Retrieved May 20, 2020 . 
37. ↑ Der Spiegel: Porsche 918 RSR: Racing laboratory with a racing rotor. www.spiegel.de , January 11, 2011, accessed on November 25, 2011 : “As a small reminiscence […] the start number 22 sticks to the doors and the front hood. It is supposed to commemorate the legendary victory of Helmut Marko and Gijs van Lennep von Remember in Le Mans in 1971, [...] " 

This version was added to the list of articles worth reading on April 28, 2012 .