Today’s featured car is a little different to others. We mostly feature road cars that have also have been raced and have some race history behind them. Today we are featuring a famous race car that was also made into a road car, well at least two were.

The Porsche 917, probably the most famous race car built by Porsche, is the car 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, or 5 litres, the 917/30 variant was capable of a 0-62 mph (100 km/h) time of 2.3 seconds, 0–124 mph (200 km/h) in 5.3 seconds, and a top speed of over 240 mph (390 km/h).

There are at least nine variants of the 917. The original version had a medium-long tail with flippers, but had considerable handling problems at high speed because of poor bodywork aerodynamics. The Weyer-Gulf team then experimented with a shorter tail, and solved the aerodynamic and handling problems at testing sessions at the Österreichring, at the expense of some top speed. Porsche adopted these changes into the 917K, which dominated in the 1970 and 1971 World Sportscar Championships. In 1971, a variant of the 917K appeared with an altered tail and shark fins, which together reduced drag and maintained down force. These versions produced around 620 bhp. There were also streamlined versions for Le Mans (1970 917L and 1971 917LH) that were 20 mph faster in a straight line. In 1971 Jo Siffert raced an open-top 917PA Spyder (normally aspirated) in the 1971 CanAm series. There is also the “Pink Pig” aerodynamic research version (917/20), and the turbocharged 917/10 and 917/30 CanAm Spyders. Porsche 917s also raced in the European Interseries in various configurations. In the 1973 Can-Am series, the turbocharged version Porsche 917/30 developed 1,100 bhp (820 kW).

The 917 is one of the most iconic sports racing cars of all time, largely for its high speeds and high power outputs, and was made into a movie star by Steve McQueen in his 1971 film Le Mans.

In an effort to reduce the speeds generated at Le Mans and other fast circuits of the day by the unlimited capacity Group 6 prototypes (such as the 7-litre Ford GT40 Mk.IV and 4-litre V12 Ferrari P) the Commission Sportive Internationale (then the independent competition arm of the FIA) announced that the International Championship of Makes would be run for three-litre Group 6 prototypes for four years from 1968 through 1971. This capacity reduction would also serve to entice manufacturers who were already building three-litre Formula One engines into endurance racing.

Well aware that few manufacturers were ready to take up the challenge immediately, the CSI also allowed the participation of five-litre Group 4 Sports Cars, of which a minimum of 50 units (later reduced to 25) had to be manufactured. This targeted existing cars like the ageing Ford GT40 Mk.I and the newer Lola T70 coupe.

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, selling the used cars to customers, they decided to conceive, design and build 25 versions of a whole new car with 4.5-litre for the Sport category with one underlying goal. To win its first overall victory in the 24 Hours of Le Mans on May 14, 1970. In only ten months the Porsche 917 was developed, based on the Porsche 908.

On March 12, 1969, a 917 was displayed at the Geneva Motor Show, painted white with a green nose and a black number 917. Brief literature on the car detailed a cash price of DM 140,000, approximately £16,000 at period exchange rates, or the price of about ten Porsche 911s. This price did not cover the costs of development.

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

The car was designed under the leadership of Piëch and Porsche chief engineer Helmuth Bott. The car was built around a very light spaceframe chassis (42 kg (93 lb)) which was permanently pressurised with gas to detect cracks in the welded structure. Power came from a new 4.5-litre air-cooled engine designed by Hans Mezger. The ‘Type 912’ engine featured a 180° flat-12 cylinder layout, twin overhead camshafts driven from centrally-mounted gears and twin spark plugs fed from two distributors. The large horizontally-mounted cooling fan was also driven from centrally-mounted gears. The longitudinally-mounted gearbox was designed to take a set of four or five gears.

To keep the car compact despite the large engine, the driving position was so far forward that the feet of the driver were beyond the front wheel axle.

The car had remarkable technology: Porsche’s first 12-cylinder engine, and many components made of titanium, magnesium and exotic alloys that had been developed for lightweight “Bergspider” hill climb racers. Other methods of weight reduction were rather simple, such as making the gear shift knob out of Balsa wood, some methods were not simple, such as using the tubular frame itself as oil piping to the front oil cooler.

Although very evident in testing that the car did not work on the track. The instability of the car was tracked down to the long tail body which was reformed and this started to give results. Here are some of them remembered,

1969
Race debut 1000Km Spa. They won with a long tail version of the car and set the fastest lap time.
Three weeks later they managed an 8th at the 1000Km Nürburgring.
1970
1st and 2nd place at le Mans 24 hour (with a 908 in 3rd). Porsche and in fact, they won all other endurance races except Sebring. The 917 on the other hand won 7 out of 8 races it entered in 1970.
On top of all the success, they had so much demand for the cars that they built the full 50 units as they were all sold.
1971
The Porsches dominated 1971. The “Pink Pig”, a heavily modified 917 won the test race at Le Mans. The white Martini 917K set a distance record of 5,335.313 Km(3,315.210 Miles) at an average speed of 220.2 km/h (137.6 mph) which stood until 2010. The same car still holds the fastest lap record at Le Mans today.
1972–1973 Can-Am
The turbocharged 850 hp (630 kW) 917/10 entered by Penske Racing won the 1972 series. The further evolution of the 917, the 917/30 won the 1973 edition winning all races but two when Charlie Kemp won the Mosport race and George Follmer won Road Atlanta and Mark Donohue won the rest.
1975
In August Porsche and Penske took their 917/30 to Talladega to break the FIA speed record on a closed circuit. With Mark Donohue driving, the average speed reached was 221.160 mph (355.923 km/h). This record stood until 1980.

Over the years they entered variety of 917s in different races and although they ran close to front, they failed to finish. Several 917 coupés as well as 917/10s (powered by turbos or NA engines) were run in Europe’s Interserie until the mid-1970s.

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

Despite the car’s impracticality, at least two 917s were road-registered:

Count Rossi of the Martini company, bought chassis 030 from Porsche. He raced it once under the Martini Racing Team Flag at the Zeltweg 1000 km World Championship race in 1971. After the race, it was returned to the factory, where it was modified with basic road equipment (exterior mirrors, turn signals, exhaust system and comfort modifications) and painted silver. None of the European authorities would certify the car for road use and Rossi obtained the Alabama plate 61-27737 to circumvent the problems.

The second, for Joachim Grossmann, was painted white and given the German registration CW-K 917. The Danish car magazine Bilen in a 1977 article details how Grossmann bought the frame and other components of the original Chassis 021 which had crashed badly at Le Mans in 1970 for 20,000 DM, rebuilt it and then modified it (examples: turn signals, hand brake, Safety glass windows and some modifications to the exhaust system) to satisfy German safety inspectors leading to the registration.

Recently, high end replicas that use the flat-6 from the 911 have become available. One is built in Australia by Kraftwerkz, another in the US by Race-Car Replicas. In addition, a grass roots “replica,” the Laser 917,. which is essentially a re bodied VW Beetle, was featured in the film Herbie Goes to Monte Carlo.

The Gulf Oil liveried 917 Kurzhecks are also prominently featured in the Steve McQueen film Le Mans competing against Ferrari’s 512 Coda Lunga.

The 917/30 was the most powerful sports car racer ever built and raced. The 5.374-litre 12 cylinder twin-turbocharged engine could produce 1,580 bhp (1,180 kW) in qualifying tune, with twin turbochargers run up to full boost, 39 psi (2.7 bar), though it usually raced with around 1,100 bhp (820 kW) at 7,800 rpm to preserve the engine. Weighing 1,800 lb (820 kg), giving it a power to weight of 1967.36 bhp/tonne in qualifying tune and 1369.68 bhp/tonne in race tune. The 917/30 dominated the Can-Am series during the 1973 season. The 917/30 could go from 0-62 mph (100 km/h) in 1.9 seconds, 0-100 mph (160 km/h) in 3.9 seconds, 0-200 mph (320 km/h) in 10.9 seconds, and on to a top speed of more than 260 mph (420 km/h). The high-level of performance and attendant fuel consumption 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 917 was also the only championship winning car in Can Am not to be powered by Chevrolet.

Videos on this amazing car here and here.
Porsche Owners Club.

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