Porsche 934

Porsche 934, used by Kremer Racing at 24 - hour race at Le Mans 1976

The Porsche 934, also called the Porsche Turbo RSR is a GT race car, which was produced from 1976 to 1977 based on the Porsche 930. Private racing teams put the after the FIA regulations of Group 4 built vehicle to 1986 in the World Sportscar Championship, the first division of the German Racing Championship ( DRM) and organized by the North American IMSA GT series a. From 1976 to 1982, the Porsche 934 drove in the 24- hour race at Le Mans.

Initially, the 934 was very successful in the DRM and IMSA GT series and scored regularly place in the top three. With advent of more powerful Porsche 935, a Group 5 car, the 934 was not a candidate for total victories more. He was henceforth used only by smaller teams and amateur racing athletes.

  • 3.1 1976 - dominance in the DRM and GT Championships
  • 3.2 1977 - success in the IMSA GT and Trans-Am series
  • 3.3 1978-1984 - The displacement by the Porsche 935
  • 3.4 1985 and 1986 - The last appearances in the IMSA GT Series
  • 3.5 The results 1976-1986
  • 6.1 Porsche database
  • 6.2 fansites on the Internet

Development and marketing

Porsche planned beginning of the 1970s for the group 4 according to FIA regulations a particularly easy built race car should be equipped with the 3- liter six- cylinder boxer engine of the Porsche 911 Carrera RS 3.0 and a turbocharger. The FIA ​​changed at short notice with effect from 1976, valid for Group 4 minimum weight, so that the planned Porsche cars would have had less chance to win. Porsche stopped then the further development and had incorporated the results so far in the design of the Porsche 930.

The following developments in the Group 4 race car based on the 930 plan was the production of at least 400 vehicles to meet the Homologationsauflagen for GT cars of Group 4. Parallel Porsche also worked on 935 for the group 5 and the 936, which should be used in Group 6 of the World Sportscar Championship in 1976. These two models were originally intended for the Porsche factory team. The 934, however, was designed from the outset for use by private teams and fulfilled the conditions that have applied for Group 4 vehicles in the GT Championship, the World Sportscar Championship and national championships.

The marketed under the name Porsche Turbo RSR Racing Car 1976 prepared in a first small batch of about 30 vehicles and sold for 108,000 DM per car. The target group was the numerous owners of a Porsche 911 Carrera RSR 3.0, which with the a powerful successor model was offered with a turbo engine 934. A year later a further ten vehicles for U.S. racing teams were produced.

Vehicle characteristics


Through the Group 4 regulations bodywork changes were very limited at the race car over the 930- series model. One of the remarkable distinctive features were the plastic extensions of the front and rear wheel arches, which are riveted to the fenders and the car serial widened on both sides to 50 mm. The high, reaching up to the lower edge of the bumper apron pointed left and right on the outside of air intakes for the two water -air heat exchanger of the charge-air cooling system. On both sides further openings were arranged inside the ventilation of the front wheel brakes. In the middle of the front apron of the oil cooler was placed. The front hood, behind which there is the trunk of the production model 930, the 934 had two round openings for the rapid refueling system. Under the hood, the fuel tank were with 120 liter capacity, the prescribed fire extinguishing system and the battery. The oil tank in the rear otherwise thus located in the engine compartment and has also been relocated to the front of the vehicle for better weight distribution. Since the use of the usual racing car in light plastic window washers as Group 4 regulations was not allowed, was awarded the Porsche 934 around the glass panes of the production model. To increase the rigidity of the body, some reinforcements have been fitted. The Porsche 934 could be ordered in all standard and special colors except metallic finishes.

In order to compete in Group 5 of the World Championship of Makes and exploit greater freedom in the vehicle body, such as a lower minimum weight, can built many race teams around their 934 after the group -5 specifications. Body side belonged to the remodeling a double rear wing on the type of 935 The conversion kit was offered directly from Porsche. The converted vehicles were referred to as Porsche 934/5.

Interior decoration

The interior of the Porsche 934 was compared to the standard model largely empty. For the driver, a racing bucket seat was fitted with six- point seat belt. The front passenger seat, rear jump seats, and the underbody panels accounted for. To secure the pilots and to increase body rigidity, a roll bar of aluminum was installed. In the dashboard next to the series instruments for engine speed, oil temperature and oil pressure additional displays for the boost pressure of the turbocharger as well as to monitor the fuel system were integrated.

Landing gear

The chassis of the GT race car had to a large extent correspond to the production model. Allows were modifications to suspension, damping, axles and brake system. The output model Porsche 930 already had a very stable suspension and wheel location. So on the front axle, the standard wheel bearings were used. The rear cast aluminum handlebars, which also corresponded to the series, only got stronger Unibal spherical plain bearings.

The regulations related high vehicle weight of 1120 kg required reinforced shock absorbers, to ensure the safety at high speeds. Among the standard torsion bars came coil springs were adjustable in height. The built-in on the rear axle novel tubular stabilizer and the stabilizer used on the front axle already in the Porsche 911 Carrera gave the 934 the necessary driving stability when entering curves.

The brake system contained parts of the Porsche 917 round were ventilated and drilled steel brake discs fitted with four-piston aluminum calipers. The brakes were addressed via two split in front and rear axle brake circuits. For better cooling of the front brakes were left and right depending on an air hose from a hole in the belly pan relocated to the brake, the brake discs forwarded it to the wind. The serial hubs have been replaced by those with central locking. This allowed not only a faster wheel change, but also ensured greater strength. The car was in front with 275/600 × 16 - delivered and rear with 325/625 × 16 tires. These were three -piece BBS light-alloy wheels in size 10J x 16 front and 12.5 J x 16 rear mounted.

Engine and transmission

Basis for the engine of the Porsche 934 was the 3-liter six-cylinder boxer engine from the 930 series vehicle with the sales name 911 Turbo 3.0. This engine was developed with the experience of racing prototype 911 Carrera RSR Turbo 2.1 on. Compared to the production engine the intake and exhaust ports have been enlarged and fitted camshaft as in racing prototype. For the first time, Porsche in a race car, a fuel injection system, a Bosch K -Jetronic, for mixture preparation a. The engine had a single ignition as in the series. To make better use of the limited space in the engine compartment, the fan for cooling the engine was installed horizontally. The turbocharger of the Porsche 917 acquired with bypass valve for controlling the maximum boost pressure was sitting similar to the production car below the rear bumper. The charge air to the turbocharger was cooled with two air-water heat exchangers. These were located to the left and right of the horizontal fan and connected by a water-filled pipe system with two water-air heat exchangers in the front apron. The one with a ratio of 6.5: 1 compressed engine developed at a speed of 7000 rpm initially a maximum of 357 kW ( 485 hp). In order for the racing engine had almost twice the engine power as the starting point of the 930, with its 191 kW (260 hp).

At the four-speed manual transmission only a few changes were necessary compared with the series since Porsche had designed already in the construction of a 930 transmission and a clutch, which coped with the higher demands of motorsport. The synchronization of the series corresponded to the transmission. To keep the temperature of the transmission low, a transmission oil cooler is installed in the rear wing. The translation of each passage could be changed as required. In order to reduce the slip of the rear wheels when accelerating out of curves, a limited slip differential was installed at the factory, which developed a maximum blocking effect of 80 %. The switching paths were shortened compared with the standard gear of the Porsche 930. With the longest gear ratio of the Porsche 934 reached a top speed of 303 km / h

In 1977, the engine power was increased by increasing the maximum boost pressure. The ten delivered to the U.S. vehicles contributed at the same speed of 7000 rpm 397 kW ( 540 hp). In the expansion stage of the 1979 engine developed with an unchanged displacement of 2993 cc ( minus the turbo factor of 1.4 yielded the 4,200 cc ) its maximum power of 441 kW ( 600 hp) at 7200 rpm. This was achieved through larger intake and exhaust valves, a higher compression ratio of 7.0: 1 instead of 6.5: 1 and by raising the maximum boost pressure to 1.7 bar. To compensate for the higher thermal loading of the engine, an oil tank increased to 22 liters and a larger oil cooler were installed. In conjunction with the four-speed manual gearbox, the unchanged now 1130 kg heavy car reached a top speed of 305 km / h

Racing history

1976 - dominance in the DRM and GT Championships

The used in the World Sportscar Championship and constructed according to the Group 4 regulations Porsche 934 won all the races in the GT class. Together with the Porsche 935 Martini Racing of the factory teams and the Kremer team and with the many used by private teams Porsche 934/5 Porsche won for the fourth time the manufacturers' world championship in 1969, 1970 and 1971.

At the 24 - hour race in Le Mans an official appointed by the French Porsche dealer Louis Meznarie and driven by Hubert Striebig, Anne -Charlotte Verney and Hughes cherry Offer Porsche 934 reached the 11th place in the overall standings. The 934 Team Gelo Racing ( Owner: Georg Loos ) and Kremer Racing came up with the places 16 and 19

The in the first division of the German Racing Championship ( DRM) used 934 were significantly superior to the other vehicles like the Porsche 911 Carrera RSR 3.0, Ford Capri RS 3100 and Opel Commodore. The previously accustomed to winning Carrera RSR 3.0 with 253 kW ( 345 hp ) hardly had a chance to win. In ten DRM - runs of victory went nine times to a 934 only at the race in Kassel- Calden was a Carrera RSR 3.0, driven by Jürgen Neuhaus, a victory. Despite the dominance of the Porsche 934 in the first division gained Hans Heyer, who raced in the second division with a Ford Escort RS, the championship title.

In the European Championship for GT cars six times a Porsche 934 reached the overall victory in seven races. Only the 300 - km race at the Nürburgring, which was also Group 6 race cars were allowed to participate, Reinhold Joest drove to first place with a Porsche 908/ 4 Turbo. European champion Toine Hezemans on a 934 of the Gelo Racing Team. After the 1976 season, the GT Championship has been set.

In the U.S. Trans-Am series, George Follmer secured on a Porsche 934 the title. Total won is occurring in this Trans-Am season 934 three out of eight runs.

1977 - success in the IMSA GT and Trans-Am series

After the Porsche 935 also sold to private racing teams of around 150 kg heavier and about 66 kW (90 hp) was less powerful 934 basically no longer competitive to drive on podium placements. Especially in the World Sportscar Championship, many financially strong teams constituted the Porsche 935. The 934 was often used by amateur racers and smaller racing teams, which usually took the car in endurance racing only on courses in the field of rank five to ten. Only the 6-hour race at Mosport in 1977 won by Paul Miller and Ludwig Heimrath with the Porsche 934 an overall victory in a World Championship race.

At the 24 - hour race at Le Mans in 1977 piloted Bob Wollek, JP "Steve" Wielemans and Philippe Gurdjian the Porsche 934 of the Kremer Racing Team on the 7th place in the overall standings, thus improving the previous result.

With the approval of Group 5 racing car for the first division and the sale of 935 to customer teams could no longer build 934 in the DRM of the great successes of the previous year. All victories in the ten races of the 1977 season have been run with the 935. The best results achieved a 934 Edgar Dören and Volkert Merl with fourth burst in three races. German racing champion Rolf Stommelen with a Porsche 935 of the Gelo Racing Team.

In the Trans-Am series of 934 was used even more successful than 1976. In a total of eleven races in the 934 and 934/5 were victorious ten times. Only the 6-hour race at Watkins Glen, in which even the Porsche 935 was approved, the victory went to Jacky Ickx and Jochen Mass with the Werks-935/77 of Martini Racing. The Trans-Am Championship title won by the Canadians Ludwig Heimrath his Porsche 934

The IMSA had specially set up in 1977 a race series for GT cars, the cars of the GTU and GTO class, later also launched prototypes of the GTP class. The Porsche used in the GTO class 934 in 1977 piloted in four races on the first rank. Despite the good finishes the 934 race car was the IMSA GT title at Al Holbert, who won four races with his Chevrolet Monza.

1978-1984 - The displacement of the Porsche 935

The started in the World Sportscar Championship 1978-1982 934 were mostly class winner of the GT class. However, the powerful Group 5 racing cars like the Porsche 935, BMW 320i 1980 Lancia Beta Monte Carlo were so numerous in the race that Porsche -934 - driver in those years in the overall standings at best, places seven to ten reached. From 1979 started in parallel also sports car prototypes of group 6 in the world championship races, against which the Group 4 racing car was also a chance. The best race result with a 934 during the same period Edgar Dören and Angelo Pallavicini with the 6 - hour race in 1981 Pergusa occupied the fourth place in the overall standings. So the 934 was used by fewer and fewer teams and amateur racers, many of whom umstiegen instead on a Porsche 935 or from 1981 offered cheaper Porsche 924 Carrera GTR. Of 934 1982 was last used in the World Sportscar Championship, as from the 1983 season only racing cars of the groups B and C were admitted.

The best finish with a 934 in the 24- hour race at Le Mans in 1979 reached the Swiss Herbert Müller, Angelo Pallavicini and Marco Vanoli who drove up to fourth place overall.

In the seasons of the Trans-Am series in 1978 and 1979 only a few drivers constituted the 934. There, the more powerful Porsche have now also 935 or the American models Chevrolet Monza and Chevrolet Corvette preferred. The last top ten placement for a 934 in the Trans-Am series reached 1979 Roy Woods from Vasek Polak Racing Team race at Laguna Seca. He went there with the Group 4 race car on the 8th place overall. From 1980, the 934 and the 935 from starting up in the Trans-Am series.

In the IMSA GT series, the Porsche 934 was also used in 1978 by only a few racing teams. The best rankings achieved in 1978 the brothers Bill and Don Whittington, who entered every race each with a 934/5 and 935, taking turns on the vehicles. In the 100-mile race at Sears Point piloted Don Whittington to 934/5 on the second rank. After that, the 934 was driven only sporadically in the IMSA GT Series. However, the U.S. racer Chester Vincentz denied his Electrodyne Racing team between 1982 and 1984 again complete IMSA GT season on a 934 and finished the race with regularly finishes among the top ten from. 1983 also put the team Personalized Autohaus around the driver Wayne Baker a Porsche 934 in the IMSA GT series a. The 12- hour race at Sebring Baker, Jim Mullen and Kees Nierop reached by car an unexpected success when they finished the race as the winner.

1985 and 1986 - The last appearances in the IMSA GT Series

At the latest with the approval of Group C racing cars like the Porsche 962 from 1985 in the IMSA GT Series GTP class was about ten years old Porsche 934 - also known as Group 5 version - technically obsolete. However, few teams started continue with their Group 4 cars in the GTO class whose races were held separately from the GTP. The best result with a 934 reached in 1986 Vincentz Chester, who finished second place overall in the race from Road Atlanta.

After the IMSA GT 1986 season of the Porsche 934 was no longer used in circuit racing with Championship Regulations. Thus ended the ten-year history of the use of this successful GT racing car.

The results 1976-1986

In the tables, each race a maximum in the top ten lists on which a Porsche 934 placed.


The Porsche 934 was produced from 1976 to 1977 in the following versions and modified in 1979: