Porsche 959

The Porsche 959 is a sports car manufactured by German automobile manufacturer Porsche from 1986 to 1993, first as a Group B rally car and later as a road legal production car designed to satisfy FIA homologation regulations requiring at least 200 units be produced.

The twin-turbocharged 959 was the world's fastest street-legal production car when introduced, achieving a top speed of , with some variants even capable of achieving . During its production run, the 959 was considered as the most technologically advanced road-going sports car ever built, and forerunner of all forthcoming sports cars. It was one of the first high-performance sports cars with all-wheel drive, providing the basis for Porsche's first all-wheel drive 911 Carrera 4 model. Its performance convinced Porsche executives to make all-wheel drive standard on all turbocharged versions of the 911 starting with the 993. The twin-turbo system utilised on the 959 also made its way to future turbocharged Porsche sports cars. In 2004, Sports Car International named the 959 number one on its list of Top Sports Cars of the 1980s.

Development history and overview

Development of the 959 (originally called the Gruppe B) started in 1981, shortly after the company's then-new Managing Director, Peter Schutz, took his office. Porsche's chief engineer at the time, Helmuth Bott, approached Schutz with some ideas about the Porsche 911, or more aptly, a new one. Bott knew that the company needed a sports car that they could continue to rely on for years to come and that could be developed as time went on. Curious as to how much they could do with the rear-engined 911, Bott convinced Schutz that development tests should take place, and even proposed researching a new all wheel drive system. Schutz agreed, and gave the project the green light. Bott also knew through experience that a racing program usually helped to accelerate the development of new models. Seeing Group B rally racing as the perfect arena to test the new development mule and its all wheel drive system, Bott again went to Schutz and got the approval to develop a car, based on his development mule, for competition in Group B.

The powerplant is a sequential twin-turbocharged DOHC flat-six engine equipped with 4 valves per cylinder, fuel fed by Bosch Motronic 2.1 fuel injection with air-cooled cylinders and water-cooled heads, with a bore x stroke of  for a total displacement of . It was coupled to a unique manual transmission offering five forward speeds plus a "gelände" (terrain) off-road gear, as well as reverse. The engine was largely based on the 4-camshaft 24-valve powerplant used in the Porsche 956 and 962 race cars. These components allowed Porsche to extract  at 6,500 rpm and  of torque at 5,000 rpm from the compact and efficient power unit. The use of sequential twin turbochargers rather than the more usual identical turbochargers for each of the two cylinder banks allowed for smooth delivery of power across the engine speed band, in contrast to the abrupt on-off power characteristic that distinguished Porsche's other turbocharged engines of the period. The engine was used virtually unchanged in the 959 road car as well.

To create a rugged, lightweight shell, Porsche adopted an aluminium and Aramid (Kevlar) composite for the body panels and chassis construction along with a Nomex floor, instead of the steel floor normally used on their production cars.

Porsche also developed the car's aerodynamics, which were designed to increase stability, as was the automatic ride-height adjustment that became available on the road car (961 race cars had a fixed suspension system). Its drag coefficient was as low as 0.31 and aerodynamic lift was eliminated completely.
 
The 959 also featured Porsche-Steuer Kupplung (PSK) all-wheel-drive system. Capable of dynamically changing the torque distribution between the rear and front wheels in both normal and slip conditions, the PSK system gave the 959 the adaptability it needed both as a race car and as a "super" street car. Under hard acceleration, PSK could send as much as 80% of the available power to the rear wheels, helping make the most of the rear-traction bias that occurs at such times. It could also vary the power bias depending on road surface and grip changes, helping maintain traction at all times. The dashboard featured gauges displaying the amount of rear differential slip as well as transmitted power to the front axle. The magnesium alloy wheels were unique, being hollow inside to form a sealed chamber contiguous with the tyre and equipped with a built-in tyre pressure monitoring system.

The 959 was actually produced at Karosserie Baur, not at the Porsche factory in Zuffenhausen, on an assembly line with Porsche inspectors overseeing the finished bodies. Most of Porsche's special order interior leather work was also done by the workers at Baur.

The 1983 Frankfurt Motor Show was chosen for the unveiling of the Porsche Group B prototype. Even in the closing hours of October 9, finishing touches were being applied to the car to go on display the next morning. After the first two prototypes, the bodywork was modified to include air vents in the front and rear wheel housings, as well as intake holes behind the doors. The first prototype receiving those modifications was code named "F3", and was destroyed in the first crash test.

The road version of the 959 debuted at the 1985 Frankfurt Motor Show as a 1986 model, but numerous issues delayed production by more than a year. The car was manufactured in two levels of trim, "Sport" and "Komfort", corresponding to the trim with more creature comforts and a more track focused trim. First customer deliveries of the 959 street variant began in 1987, and the car debuted at a cost of DM431,550 (US$225,000) each, still less than half what it cost Porsche to build each car. Production ended in 1988 with 292 cars completed. In total, 337 cars were built, including 37 prototypes and pre-production models. At least one 959 and one 961 remain in the Porsche historic hall in Stuttgart, Germany.

In 1992/1993, Porsche built eight more cars assembled from spare parts from the inventory at the manufacturing site in Zuffenhausen. All eight were "Komfort" versions: four in red and four in silver. These cars were much more expensive (DM 747,500) than the earlier ones. The later cars also featured a newly developed speed-sensitive damper system. The cars were sold to selected collectors after being driven by works personnel for some time and are today by far the most sought-after 959 models.

Performance

Test results for the 959 "Sport" (450 PS):

 0–: 3.6 seconds
 0–: 8.2 seconds
 0–: 3.7 seconds
 0–: 5.1 seconds
 0–: 6.3 seconds
 0–: 7.9 seconds
 0–: 9.6 seconds
 0–: 11.4 seconds
 0–400 m ( mile): 11.8 seconds at 
 Standing kilometre: 21.6 seconds at 
 Top Speed: 

Test results for the 959 "Komfort" version (450 PS):
 0–: 1.5 seconds
 0–: 2.2 seconds
 0–: 2.9 seconds
 0–: 3.6 seconds
 0–: 4.8 seconds
 0–: 5.8 seconds
 0–: 7.1 seconds
 0–: 8.8 seconds
 0–: 10.4 seconds
 0–: 12.4 seconds
 0–: 15.9 seconds
 0–: 19.2 seconds
 0–: 22.5 seconds
 -: 11.9 seconds, using 6th gear (~1,786 rpm)
 -: 8.8 seconds, using 6th gear
 Standing  mile (402 m): 12.0 seconds at 
 Braking : 166 ft (50 m)
 Top speed: 

If desired, even more power was available to customer cars by Porsche. According to Paul Frère there was an optional  factory upgrade, with an increased top speed of  along with the 0–100 km/h (62 mph) acceleration time reduced to 3.4 seconds.

Porsche 959S 

The Porsche 959 S was a 959 "Sport" with larger turbochargers that increased power output to  thus resulting in a top speed of  as tested by Auto, Motor und Sport at the Nardò Ring in 1988. Twenty-nine cars were built.

Racing

Group B / Paris–Dakar Rally

The 959 was originally meant for Group B racing but development time took longer than expected. The first development race cars, essentially modified 911 Carrera models with all-wheel-drive system known internally as the 953, were entered in the 1984 Paris-Dakar Rally, finishing 1st (René Metge), 6th (Jacky Ickx) and 25th. These cars tested the all-wheel-drive system to be used in the 959. Unlike the World Rally Championship the Dakar didn't require a minimum number of cars built for homologation. In 1985, three cars were entered in the Dakar rally with the proposed 959 body and the rest of the systems but they still used the engine of the 953 rally cars. These cars didn't finish (only one due to mechnical failure however). Afterwards Porsche fitted the cars with twin-turbochargers. Two cars started at the Rallye des Pharaons in October 1985. One of them caught fire, while Saeed Al-Hajri and John Spiller achieved a commanding victory with their 959. At the 1986 Paris-Dakar Rally the 959 finished 1st (René Metge), 2nd (Jacky Ickx) and 6th.

By the time the 959 was ready for production and homologation in 1987, the Group B programme was cancelled altogether a year prior thus ending Porsche's participation in Group B.

LeMans and IMSA

The 959 was modified for LeMans class racing (now called the 961) and participated in the 1986 and 1987 seasons. It also participated once in IMSA class racing.

In 1986, the racing variant of the 959, the Porsche 961, made its debut at the 24 Hours of Le Mans. Driven by René Metge partnering Claude Ballot-Léna, it finished first in its class and 7th overall. It returned in 1987 but while in 11th place Canadian/Dutch driver Kees Nierop mis-shifted from 6th into 2nd gear and crashed into the guard-rail. Upon re-joining the track, the car was observed on TV monitors in the Porsche pits to be on fire and the driver was told to stop and get out of the car. Sadly Nierop pulled over between marshal stations and this extra time taken to get to the car by the marshals allowed the fire to consume most of the rear end and destroy the car. It was later repaired and put on display at the Porsche Museum.

Canepa Design modifications
In 2003, Canepa Design initiated a 959 upgrade program. By making modifications to the 959's turbochargers, exhaust system and computer-control systems, Canepa enabled the 959 to pass emissions requirements (thereby making it street-legal in the United States). The new configuration allowed parallel turbo charging and simplified diagnostics. Canepa also modified the 959's lightweight magnesium wheels in order to fit it with tyres without the unique Dunlop Denloc bead. Modern Michelin high-performance tyres capable of handling the increased performance could then be mounted. The original RE71 tires were available in the U.S. and have always been more than capable of handling the power output of the 959.

In April 2018, Canepa announced the Generation III package for the 959. The package includes the replacement of the standard sequential twin-turbo system with a pair of Borg Warner parallel twin-turbochargers, new wiring harness and a new engine control unit along with a new exhaust system and a new clutch to handle the extra power produced by the car. The package enables the engine to produce  and  of torque. The package also includes the replacement of the standard suspension system with an evolution of the 959 S' suspension system fitted with modern dampers and titanium springs for improved handling and ride-height along with new tyres. The headlamps are replaced with new Xenon headlamps, providing better illumination than the original units.

In addition to the package, Canepa also introduced a production of the 959 SC (Sport Canepa) limited to 50 cars. The 959 SC comes standard with the Generation III Canepa upgrade along with a body overhaul and a new paint-to-sample paint job according to the customer's desire that takes 500 hours to complete. The car also features a reworked leather interior which is complemented with a steering wheel having hand-stitched leather and a more modern sound system with the interior alone taking 300 hours to complete. The process starts with a standard 959 and its teardown to the chassis with every rusty part replaced and every component coated with zinc. The package costs in excess of US$2 million including the cost of the car itself.

Legality in the United States 
The 959 was not street legal in the United States prior to 1999 when the "Show or Display" law was passed, although an unknown number were imported via the "grey market" during the late 1980s as show pieces. Porsche didn't provide the United States Department of Transportation with four cars required for crash testing, so the car was never certified by the National Highway Traffic Safety Administration for street use in the U.S. In 2001, with the passage of "Show and Display", the crash test requirements were removed and import of the 959 was allowed, assuming the car could meet the emissions standards applicable in 1987. The 959 could be fitted with a catalytic converter and a re-programmed computer which allowed it to meet those emissions requirements. As the 959 was a  pre-1996 car, it was not required to pass any emissions testing; due to the fact that all cars are now over 25 years old and are therefore completely legal for US import, they are no longer required to comply with show and display laws.

Microsoft founder Bill Gates bought a 959 before the model had Department of Transportation and Environmental Protection Agency approval. The car was stored for 13 years by the Customs Service at the Port of San Francisco, until the Show or Display rule came into force.

Notes

References
 Bowler, M. & Wood, J. (1997). The Fastest Cars from Around the World. Parragon. .
 Frère, P. (1999). Porsche 911 Story (sixth edition). Patrick Stevens Limited. .
 Kim, Daniel (2015). "Porsche 959: The Greatest Porsche of All-Time?" Exotic Car List.
 
 Wood, J. (1997). Porsche: The Legend. Parragon. .

External links

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Category:All-wheel-drive vehicles
Category:Cars powered by boxer engines
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Category:Group B cars
Category:Rally cars
Category:Rear-engined vehicles
Category:Sports cars
Category:Cars introduced in 1986