Porsche 934

Porsche
Porsche 934, used by Kremer Racing in the 1976 Le Mans 24-hour race
934
Production period:	1976-1977
Class :	race car
Body versions :	Coupe
Engines:	Petrol engines : 3.0 liters (357–441 kW)
Length:	4291 mm
Width:	1875 mm
Height:	1304 mm
Wheelbase :	2268-2271 mm
Empty weight :	1120-1130 kg
Previous model	Porsche 911 Carrera RSR 3.0

The Porsche 934 , also known as the Porsche Turbo RSR , is a GT racing car that was produced from 1976 to 1977 based on the Porsche 930 . Private racing teams used the vehicle built according to the FIA regulations of group 4 until 1986 in the sports car world championship , the 1st division of the German racing championship (DRM) and the GT series organized by the North American IMSA . From 1976 to 1982 the Porsche 934 drove in the Le Mans 24-hour race .

Initially, the 934 was very successful in the DRM and IMSA GT series and regularly achieved placements in the top three. With the advent of the more powerful Porsche 935 , a Group 5 vehicle, the 934 was no longer an aspirant for overall victories. From then on it was only used by smaller teams and amateur racing athletes.

Development and marketing

In the early 1970s, Porsche planned a particularly lightweight racing car for Group 4 in accordance with FIA regulations, which was to be equipped with the 3-liter six-cylinder boxer engine from the Porsche 911 Carrera RS 3.0 and a turbocharger. The FIA ​​changed the minimum vehicle weight valid for Group 4 at short notice with effect from 1976, so that the car planned by Porsche would have had fewer chances of victory. Porsche then stopped further development and incorporated the previous results into the design of the Porsche 930 .

The following developments of the Group 4 racing car were based on the 930. The plan was to manufacture at least 400 vehicles in order to meet the homologation requirements for Group 4 GT vehicles. At the same time, Porsche also worked on the 935 for Group 5 and on the 936 , which was to be used in Group 6 of the Sports Car World Championship from 1976. These two models were originally intended exclusively for the Porsche works team. The 934, on the other hand, was intended for use by private teams from the start and met the requirements that applied to Group 4 vehicles in the European GT Championship, the World Sports Car Championship and national championships.

The racing car marketed under the name Porsche Turbo RSR was produced in 1976 in a first small series of around 30 vehicles and sold for 108,000 DM per car. The target group were the numerous owners of a Porsche 911 Carrera RSR 3.0 , who were offered the 934, a powerful successor model with a turbo engine. A year later another ten vehicles were produced for US racing teams.

Vehicle characteristics

body

Front view of a Porsche 934 with the characteristic front spoiler

Due to the Group 4 regulations, body changes in the racing car were very limited compared to the 930 series model. One of the most noticeable distinguishing features were the plastic extensions of the front and rear fenders, which were riveted onto the standard fenders and widened the car by 50 mm on both sides. The high front apron reaching to the lower edge of the bumper had air inlets on the outside left and right for the two water-air heat exchangers of the charge air cooling system. The openings on both sides further inwards were used to ventilate the front brakes. The oil cooler was placed in the middle of the front apron. The front hood, under which the trunk is hidden on the 930 series model, had two round openings for the quick tank system on the 934. The fuel tank with a capacity of 120 liters, the prescribed fire extinguishing system and the battery were located under the hood. The oil tank, which is otherwise located in the engine compartment and thus in the rear, was also relocated to the front of the vehicle because of the better weight distribution. Since the use of the light plastic window panes usually used in racing cars was not permitted according to the Group 4 regulations, the Porsche 934 received the glass panes of the production model all around. To increase the rigidity of the body, some reinforcements were built in. The Porsche 934 could be ordered in all standard and special colors with the exception of metallic paintwork.

In order to compete in group 5 of the brand world championship and to be able to use more freedom in vehicle construction, such as a lower minimum weight, many racing teams converted their 934s according to the group 5 specifications. On the body side, the conversion included a double rear wing in the style of the 935. The conversion kit was offered directly by Porsche. The converted vehicles were called Porsche 934/5 .

Interior

The interior of the Porsche 934 was largely empty compared to the production model. A racing bucket seat with a six-point seat belt was installed for the driver. The passenger seat, the rear emergency seats and the floor panels were omitted. An aluminum roll bar was installed to secure the pilot and to increase the rigidity of the body. In addition to the standard instruments for the engine speed, oil temperature and oil pressure, additional displays for the boost pressure of the turbocharger and for monitoring the fuel system were integrated in the dashboard.

landing gear

The chassis of the GT racing cars had to correspond to a large extent to that of the production model. Modifications to the suspension, damping, axles and braking system were permitted. The starting model Porsche 930 already had a very stable wheel suspension and wheel guidance. The standard wheel bearings were used on the front axle. The rear cast aluminum handlebars, which also corresponded to the series, only received more solid Unibal spherical bearings.

Porsche 934 with BBS light alloy wheels and Jägermeister paintwork by the Max Moritz team, as used in the 1976 World Championship

The regulation-related high vehicle weight of 1120 kg required reinforced shock absorbers to ensure safety at high speeds. In addition to the standard torsion bar springs, there were coil springs that were adjustable in height. The new tubular stabilizer built into the rear axle and the stabilizer already used on the front axle in the Porsche 911 Carrera gave the 934 the necessary driving stability when entering bends.

The braking system contained parts of the Porsche 917 . All around the car had internally ventilated and perforated metallic brake discs with four-piston aluminum brake calipers. The brakes were addressed via two brake circuits divided into front and rear axles. For better cooling of the front wheel brakes, an air hose was laid on the left and right from an opening in the front spoiler to the brake, which led the wind to the brake discs. The standard wheel hubs were replaced by those with central locking. This not only enabled faster wheel changes, but also resulted in greater strength. The car was delivered with 275/600 × 16 tires at the front and 325/625 × 16 tires at the rear, which were mounted on three-piece BBS alloy wheels measuring 10 J × 16 at the front and 12.5 J × 16 at the rear.

engine and gears

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

Only a few changes were necessary to the four-speed manual gearbox compared to the series, as Porsche had already designed a gearbox and clutch when designing the 930 that could cope with the higher loads in motorsport. The synchronization corresponded to that of the series transmission. To keep the temperatures of the transmission low, a transmission oil cooler was installed in the rear wing. The translation of each gear could be changed as required. In order to reduce the slip of the rear wheels when accelerating out of bends, a limited slip differential was installed, which developed a maximum locking effect of 80%. The shift travel was shortened compared to the series transmission of the Porsche 930. With the longest gear ratio, the Porsche 934 reached a top speed of 303 km / h.

In 1977 the engine output was increased by increasing the maximum boost pressure. The ten vehicles delivered to the USA developed a maximum of 397 kW (540 hp) at the same engine speed of 7000 rpm. In the expansion stage of 1979, the engine developed its maximum possible output of 441 kW (600 hp) at 7200 rpm with unchanged displacement of 2993 cm³ (multiplied by the turbo factor of 1.4 this resulted in around 4200 cm³). This was achieved through larger intake and exhaust valves, a higher compression of 7.0: 1 instead of 6.5: 1 and by increasing the maximum boost pressure to 1.7 bar. To compensate for the higher thermal load on the engine, an oil tank enlarged by 22 liters and a larger oil cooler were installed. In conjunction with the unchanged four-speed gearbox, the now 1130 kg car reached a top speed of 305 km / h.

Racing history

1976 - Dominance in the DRM and GT European Championship

Porsche 934 with conversion to Group 5 Porsche 934/5

The Porsche 934s used in the Sports Car World Championship and built according to Group 4 regulations won the GT class in all races. Together with the Porsche 935s of the Martini Racing works team and the Kremer team and with the many Porsche 934/5 used by private teams, Porsche won the brand world championship for the fourth time after 1969, 1970 and 1971.

At the 24 Hours of Le Mans , a Porsche 934 entered by the French Porsche dealer Louis Meznarie and driven by Hubert Striebig , Anne-Charlotte Verney and Hughes Kirschoffer achieved 11th place in the overall standings. The 934 teams of Gelo Racing (owner: Georg Loos ) and Kremer Racing came in 16th and 19th.

The 934s used in the 1st division of the German Racing Championship (DRM) were clearly superior to the other vehicles such as the Porsche 911 Carrera RSR 3.0, Ford Capri RS 3100 and Opel Commodore . The Carrera RSR 3.0 with 253 kW (345 PS), which had been used to victory so far, hardly had a chance of victory. In ten DRM races, a 934 won nine times. Only in the Kassel-Calden race was a Carrera RSR 3.0, driven by Jürgen Neuhaus , a winner. Despite the dominance of the Porsche 934 in the 1st division, Hans Heyer , who competed in the 2nd division with a Ford Escort RS , won the championship title.

In the European Championship for GT vehicles, a Porsche 934 achieved overall victory six times in seven races. Reinhold Joest only took first place in a Porsche 908/4 Turbo in the 300 km race at the Nürburgring, in which Group 6 racing cars were also allowed to take part . Toine Hezemans became European champion on a 934 of the Gelo Racing Team. After the 1976 season, the European GT Championship was discontinued.

In the US Trans-Am series , George Follmer secured the title in a Porsche 934. Overall, the 934 contested this Trans-Am season won three out of eight races.

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

After Porsche also sold the 935 to private racing teams, the 934, which was around 150 kg heavier and around 66 kW (90 hp) less powerful, was no longer able to compete on the podium. In the sports car world championship in particular, many financially strong teams used the Porsche 935. The 934 was often used by amateur racers and smaller racing teams, who mostly only drove their cars to places in the fifth to tenth place in the endurance races. Only in the 6-hour race in Mosport in 1977 did Paul Miller and Ludwig Heimrath achieve an overall victory in a world championship run with the Porsche 934.

At the 24-hour race at Le Mans in 1977 , Bob Wollek , JP “Steve” Wielemans and Philippe Gurdjian drove the Kremer Racing Team's Porsche 934 to 7th place in the overall standings, thus improving the previous year's result.

With the approval of Group 5 racing cars for the 1st Division and the sale of the 935 to customer teams, the 934 in the DRM could no longer build on the great successes of the previous year. All victories in the ten races of the 1977 season were achieved with the 935. The best results of a 934 were achieved by Edgar Dören and Volkert Merl with fourth places in a total of three races. German racing champion was Rolf Stommelen with a Porsche 935 from the Gelo Racing Team.

In the Trans-Am series, the 934 was used even more successfully than in 1976. The 934 and 934/5 have won ten times in a total of eleven races. Only in the 6-hour race in Watkins Glen, where the Porsche 935 was also registered, did Jacky Ickx and Jochen Mass with the works 935/77 from Martini Racing win. The Canadian Ludwig Heimrath won the Trans-Am championship with his Porsche 934.

The IMSA founded a racing series especially for GT vehicles in 1977, in which cars of the GTU and GTO classes, and later prototypes of the GTP class, started. The Porsche 934s used in the GTO class were driven to first place in a total of four races in 1977. Despite the good placements of the 934 racing cars, the IMSA GT title went to Al Holbert , who won four races in his Chevrolet Monza .

1978 to 1984 - The displacement by the Porsche 935

The 934s, which started in the sports car world championship between 1978 and 1982, were mostly class winners in the GT class. However, the more powerful Group 5 racing cars such as the Porsche 935, BMW 320i and, from 1980, the Lancia Beta Montecarlo were so numerous in the races that the Porsche 934 drivers in those years only finished seventh to tenth at best in the overall standings achieved. From 1979 onwards, Group 6 sports car prototypes also started in the world championship races , against which the Group 4 racing car also had no chance. The best race result with a 934 during this period was achieved by Edgar Dören and Angelo Pallavicini , who finished fourth in the overall standings in the 1981 6-hour race in Pergusa . The 934 was used by fewer and fewer teams and amateur racing drivers, many of whom switched to a Porsche 935 or the cheaper Porsche 924 Carrera GTR, which was offered from 1981 . In 1982 the 934 was used for the last time in the sports car world championship, since from the 1983 season only racing cars in groups B and C were permitted.

The best place with a 934 at the 24 Hours of Le Mans was achieved in 1979 by the Swiss Herbert Müller , Angelo Pallavicini and Marco Vanoli , who finished fourth overall.

Few drivers used the 934 in the 1978 and 1979 Trans-Am series seasons. The more powerful Porsche 935 or the American models Chevrolet Monza and Chevrolet Corvette were also preferred there. The last top ten placement for a 934 in the Trans-Am series was achieved in 1979 by Roy Woods of the Vasek Polak Racing Team at the Laguna Seca race . There he drove the Group 4 racing car to 8th place overall. From 1980 the 934 and the 935 no longer started in the Trans-Am series.

In the IMSA GT series, the Porsche 934 was also only used by a few racing teams from 1978. The best placings were achieved in 1978 by the brothers Bill and Don Whittington , who entered each race with a 934/5 and a 935, alternating between vehicles. In the 100 mile race at Sears Point , Don Whittington drove the 934/5 to second place. After that, the 934 was only driven sporadically in the IMSA GT series. However, the US racing driver Chester Vincentz and his Electrodyne Racing Team contested complete IMSA GT seasons on a 934 again between 1982 and 1984 and regularly finished the races with placements among the top ten. In 1983, the Personalized Autohaus team led by driver Wayne Baker also used a Porsche 934 in the IMSA GT series. At the 12-hour race at Sebring, Baker, Jim Mullen and Kees Nierop achieved an unexpected success with the car when they finished the race as winners.

1985 and 1986 - The last outings in the IMSA GT series

At the latest with the approval of Group C racing cars such as the Porsche 962 from 1985 in the GTP class of the IMSA GT series, the ten-year-old Porsche 934 - also as a Group 5 version - was technically outdated. However, a few teams continued to start with their Group 4 cars in the GTO class, whose races were held separately from the GTP. The best result with a 934 was achieved in 1986 by Chester Vincentz, who finished second overall in the Road Atlanta race.

After the IMSA GT season in 1986, the Porsche 934 was no longer used in circuit races with championship status. This ended the ten-year history of this successful GT racing car.

The results from 1976 to 1986

In the tables, a maximum of the first ten places for each race are listed in which a Porsche 934 placed.

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

1986

Technical specifications

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

Porsche 934:	934 Turbo (1976)	934 Turbo USA (1977)	934 Turbo (1979)
Engine:	6-cylinder boxer engine (four-stroke), an exhaust gas turbocharger with two intercoolers
Displacement:	2994 cc
Bore × stroke:	95.0 x 70.4
Performance at 1 / min:	357 kW (485 hp) at 7000	397 kW (540 hp) at 7000	441 kW (600 hp) at 7200
Max. Torque at 1 / min:	588 Nm at 5400	607 Nm at 5400
Compression:	6.5: 1		7.0: 1
Valve control:	One overhead camshaft ( OHC ) with chain drive each
Cooling:	Air cooling (fan)
Transmission:	4-speed gearbox, limited slip differential , rear-wheel drive
Brakes:	Disc brakes (internally ventilated)
Front suspension:	Independent suspension on shock absorber struts and wishbones
Rear suspension:	Independent suspension on semi-trailing arms
Front suspension:	Torsion bar springs with additional adjustable coil springs and telescopic shock absorbers
Rear suspension:	Torsion bar springs with additional adjustable coil springs and telescopic shock absorbers
Body:	Self-supporting steel body with plastic parts
Track width front / rear:	1481/1506 mm
Wheelbase :	2268 mm	2271 mm
Tires rim:	VA: 275/600 × 16 on 10J × 16 HA: 325/625 × 16 on 12.5J × 16
Dimensions L × W × H:	4291 × 1875 × 1304 mm
Empty weight :	1120 kg		1130 kg
Top speed:	303 km / h		305 km / h

literature

• Jürgen Barth, Bernd Dobronz: Porsche 934/935. The complete documentation: Development • Use • History . Motorbuch-Verlag, Stuttgart 2012, ISBN 978-3-613-03348-1
• Jürgen Barth, Gustav Büsing: The big book of the Porsche types. Rear engine models . Motorbuch-Verlag, Stuttgart 2010, ISBN 978-3-613-03241-5
• Jörg Austen: Porsche 911 rally and racing cars. The technical documentation . Motorbuch-Verlag, Stuttgart 2005, ISBN 3-613-02492-6
• Peter Schneider: Type compass Porsche. Racing and racing sports cars since 1948 . Motorbuch-Verlag, Stuttgart 2003, ISBN 3-613-02300-8

Web links

Commons : Porsche 934  - collection of pictures, videos and audio files

Porsche database

• Porsche 934 Coupé on Porsche.com ( Memento from November 6, 2009 in the Internet Archive )

Fan sites on the internet

• The Porsche 934 at www.Ultimatecarpage.com (English)
• Photo series of a Porsche 934/5 on www.Canepa.com (English)

Individual evidence

1. ↑ Classicscars - Internet site: DRM race results 1976. At: www.classicscars.com , accessed on October 18, 2012 . 
2. ↑ ^{a b c d e} Dr. Ing.hc F. Porsche AG: 1976 Porsche 934 Coupé. At: www.porsche.com/germany/ , archived from the original on November 6, 2009 ; Retrieved October 18, 2012 . 
3. ↑ Autobild Video: Big Bang in the Seventies. In: www.autobild.de. February 3, 2011, accessed August 12, 2012 . 
4. ^ FIA website: Appendix J to the 1976 International Automobile Sports Act, Art. 251 / Art. 252. (PDF) (No longer available online.) At: www.fia.com , archived from the original on March 14, 2006 ; Retrieved October 18, 2012 . 
5. ^ ^{A b c d e} Jürgen Barth, Gustav Büsing: The great book of the Porsche types. Rear engine models . P. 629.
6. ↑ Jürgen Barth, Gustav Büsing: The great book of the Porsche types. Rear engine models . P. 651.
7. ^ ^{A b c d} Jürgen Barth, Gustav Büsing: The great book of the Porsche types. Rear engine models . P. 628.
8. ^ ^{A b c d e} Jürgen Barth, Gustav Büsing: The great book of the Porsche types. Rear engine models . P. 630.
9. ^ ^{A b c} Jürgen Barth, Gustav Büsing: The great book of the Porsche types. Rear engine models . P. 632.
10. ↑ Jürgen Barth, Gustav Büsing: The great book of the Porsche types. Rear engine models . P. 264.
11. ↑ ^{a b c} Ultimatecarpage.com - Internet site: Porsche 934. At: www.ultimatecarpage.com , accessed on October 21, 2012 . 
12. ↑ Classicscars - Internet site: Race results of the Sports Car World Championship 1976. At: www.classicscars.com , accessed on October 22, 2012 . 
13. ↑ Dr. Ing.hc F. Porsche AG: Brochure for the Porsche 924 World Championship model , 1977.
14. ^ Classicscars - Internet site: Le Mans race results 1976. At: www.classicscars.com , accessed on October 22, 2012 . 
15. ↑ Teamdan - website: race results and overall placements of the DRM 1976. (No longer available online.) On: www.teamdan.com , archived from the original on September 24, 2015 ; Retrieved October 22, 2012 . 
16. ↑ Classicscars - Internet site: Race results of the European GT Championship 1976. At: www.classicscars.com , accessed on October 22, 2012 . 
17. ↑ Touringracing.net - website: GT European Championship overall results 1976. On: touringcarracing.net , accessed on October 22, 2012 . 
18. ↑ Classicscars - Internet site: Race results of the Sports Car World Championship 1977. At: www.classicscars.com , accessed on October 22, 2012 . 
19. ↑ Classicscars - Internet site: Le Mans race results 1977. At: www.classicscars.com , accessed on October 22, 2012 . 
20. ↑ Teamdan - website: race results and overall placements of the DRM 1977. (No longer available online.) On: www.teamdan.com , archived from the original on September 24, 2015 ; Retrieved October 22, 2012 . 
21. ↑ Racing Sports Cars website: 6 Hours of Watkin Glen 1977. From : www.racingsportscars.com , accessed October 22, 2012 . 
22. ↑ Classicscars - Internet site: IMSA 1977 race results. On: www.classicscars.com , accessed on October 22, 2012 . 
23. ↑ Imsahistory - website: Al Holbert. (No longer available online.) At: www.imsahistory.com , formerly in the original ; Retrieved October 22, 2012 .  ( Page no longer available , search in web archives )  
24. ↑ Classicscars - Internet site: Racing results from the 1978 World Sports Car Championship. At: www.classicscars.com , accessed on October 22, 2012 . 
25. ↑ Classicscars - Internet site: Racing results of the sports car world championship 1980. At: www.classicscars.com , accessed on October 22, 2012 . 
26. ↑ Classicscars - Internet site: Race results of the sports car world championship 1981. At: www.classicscars.com , accessed on October 22, 2012 . 
27. ↑ Classicscars - Internet site: Racing results of the Sports Car World Championship 1982. At: www.classicscars.com , accessed on October 22, 2012 . 
28. ↑ Classicscars - Internet site: Le Mans race results 1979. At: www.classicscars.com , accessed on October 22, 2012 . 
29. ^ Racing Sports Cars website: Trans-Am races from Laguna Seca 1979. At: www.racingsportscars.com , accessed on October 22, 2012 . 
30. ↑ Classicscars - Internet site: Race results of the IMSA 1978. At: www.classicscars.com , accessed on October 22, 2012 . 
31. ↑ Classicscars - Internet site: IMSA 1983 racing results. At: www.classicscars.com , accessed on October 22, 2012 . 
32. ^ Classicscars - Internet site: IMSA 1985 race results. At: www.classicscars.com , accessed on October 22, 2012 . 
33. ↑ Classicscars - Internet site: IMSA GT 1986 race results. On: www.classicscars.com , accessed on October 22, 2012 . 

This article was added to the list of articles worth reading on February 10, 2013 in this version .