Porsche’s 930 Turbo Carrera, unveiled in 1975, was the company’s fastest-ever production car to date, and the company quickly took it racing in Group 4, replacing the naturally aspirated RSR 3.0. One 934 was built for testing, after which 30 units were completed for sale to privateers.

Group 4 regulations mandated a near-standard body configuration and a minimum weight of 1120 kilograms. Removal of the stock seats, air conditioning, insulation, and other unnecessary items and installation of a full aluminum roll cage, additional gauges, and racing equipment left the 934 weighing a hair less than a well-equipped 930. Thus, the 930’s standard electric windows were retained, along with its standard rear-deck spoiler. Porsche was even able to add some weight where needed. The chassis was reinforced, including a stiff cross-brace tied into the front suspension mounts. Bilstein coil-overs were added, and wider 16-inch centre-lock BBS three-piece alloy wheels with racing tyres (235 x 10.5 front, 255 x 12 in back) required fibreglass fender extensions. Stronger hubs and brakes were borrowed from the 917. A 120-litre fuel cell and an oil tank filled the trunk area.

934s were fitted with a three-litre, flat-fan, single-turbo engine and strengthened four-speed transaxle. Unlike its predecessor, the naturally aspirated RSR 3.0, the 934 could be handful to drive. Some owners never mastered the single-turbo’s delayed power delivery; others caught on quickly and mastered the car’s habits.

According to Porsche expert Jürgen Barth, chassis 0172 was purchased new by tyre importer Richard Leder of Hamburg. Leder ran just six events with this 934, securing a victory at Kassel Calden on 9 May 1976, his fourth time out. Unfortunately, the car crashed a few weeks later on the first lap of the Nürburgring ADAC 1000 km. Then, in June, Leder tragically died in a road accident and the car passed to Volker Merl, who campaigned the car in the German National Championship, along with a number of smaller national races.

Over the end of 1976 and beginning of 1977, Merl upgraded the Porsche to 934/5 specification and was able to win at Avus in May of 1977. Merl eventually sold his 934 to a Swiss Porsche dealer, Peter Zbinden. Often paired with fellow Swiss Edi Kofel, Zbinden entered more than 30 events in 1978, 1979, and 1980, claiming no fewer than 16 class and overall wins. Zbinden converted the car to full 935 specification in 1980 before selling it to Pierre Schaerer of Bern, who ran the car primarily in Swiss championship races and hillclimbs. In 1982 the car was sold to Peter Baumann of Zurich, who used the car in club events in company with then-Porsche Sports Director Max Welti. Baumann subsequently restored the car to its original specification, appearance and livery using the original Group 4 parts previously removed and kept with the car.

Prill Porsche Classics of Halstead, Essex, were engaged by the current owner to carry out an inspection and run the car at their premises earlier this year, as is documented by accompanying paperwork. On compilation of the report, marque expert Andy Prill comments on the car’s originality, and of its formation within a collection for many years. It is said that older parts were preserved amid the period conversion of Group 4 to Group 5 specification, while Group 4 parts that were original to the 934 were retained for when the car returned to that setting. Prill stated: “The car is as good as it gets and virtually totally original. Probably the only surviving example of this quality.” Further research found that the conversion back to Group 4 specification was carried out by another marque specialist, Michael Roock of Roock Sportsystem, Germany. He stated that he maintained the 934 for a number of years and that his company undertook the conversion back to original specification using all the retained and original parts.

This 934 boasts an impressive pedigree: of 69 races entered, it recorded 18 overall victories or class wins and 29 podiums. After recommissioning, this car would be eligible for such prestigious vintage events as the Le Mans Classic, Rolex Monterey Motorsports Reunion, and others.