Porsche began experimenting with turbocharging technology on their race cars during the late 1960s, and in 1972 began development on a turbocharged version of the 911. Porsche originally needed to produce the car in order to comply with homologation regulations and had intended on marketing it as a street legal race vehicle like the 1973 Carrera 2.7 RS. The FIA's Appendix "J” rules upon which the 911 Turbo Carrera RSR 2.1 was entered into competition in 1974 changed in 1975 and 1976. The FIA announced that cars for Group 4 and Group 5 had to be production cars and be available for sale to individual purchasers through manufacturer dealer networks. For the 1976 season, new FIA regulations required manufacturers to produce 400 cars within a twenty-four-month period to gain approval for Group 4. Group 5 would require the car to be derived from a homologated model in Group 3 or 4. Porsche's Group 4 entry was the
934, homologated on 6 December 1975. For Group 5, Porsche would develop one of the most successful racing cars of the time, the
935. The 911 Turbo was put into production in 1975. While the original purpose of the 911 Turbo was to gain homologation for the 1976 racing season, it quickly became popular among car enthusiasts. Four hundred cars were produced by the end of 1975. Since Porsche wanted to compete in the 1976 season, they gained FIA
homologation for the Porsche Turbo for Group 4 in Nr. 645 on 6 December 1975 and the 1,000th 911 Turbo was completed on 5 May 1976.
Ferry Porsche gave the first Turbo model to his sister
Louise Piëch for her 70th birthday. Although this 911 Turbo No. 1 already has the large rear spoiler of the later production model, it still has the narrower bodywork of the Carrera, whose lettering at the rear has not been removed. In addition, the 911 Turbo No. 1 has only a turbocharged 2.7-litre boxer engine with 177 kW (240 hp) instead of the 3.0-litre boxer engine installed later.
Ernst Fuhrmann adapted the turbo-technology originally developed for the
917/30 CAN-AM car and applied it to the 3.0 litre flat-six used in Carrera RS 3.0, thus creating what Porsche internally dubbed as the 930. The car utilises a single
KK&K turbocharger. Total power output from the engine was at 5,500 rpm and of torque at 4,000 rpm, much more than the standard Carrera it was based on. The engine has a compression ratio of 6.5:1. In order to ensure that the platform could make the most of the higher power output, a revised suspension, larger brakes and a stronger
gearbox became part of the package, although some consumers were unhappy with Porsche's use of a four-speed transmission whilst a five-speed
manual transmission was available in the "lower trim" Carrera. A "whale tail"
rear spoiler was installed to help vent more air to the engine and to create more downforce at the rear of the vehicle, and wider rear wheels with upgraded tires combined with flared wheel arches were implemented in order to increase the car's width and grip, making it more stable. Porsche badged the vehicle simply as "Turbo" (although early U.S. units were badged as "Turbo Carrera") and introduced the vehicle at the
Paris Auto Show in October 1974 before putting it on sale in the spring of 1975; export to the United States began in 1976. The 930 proved very fast but also very demanding to drive, and due to its short wheelbase and
rear engine layout, was prone to
oversteer and turbo-lag. It acquired the nickname "the Widowmaker" after several crashes and deaths attributed to its handling characteristics, which were unfamiliar to many drivers. Under certain conditions, applying too much throttle would cause the heavy rear end of the car to swing outward like a pendulum, causing the car to spin out. To this day, Porsche corporate employees who drive 911 Turbo models for testing or for business reasons are mandated to undergo "Turbo Training", despite the fact that newer 911 Turbo models are generally safer and easier to drive. Porsche made its first and most significant changes to the 930 for 1978 model year, enlarging the engine bore by to a total displacement of and adding an air-to-air
intercooler. By cooling the pressurised air charge, the intercooler helped increase power output to at 5,500 rpm and of torque at 4,000 rpm (
DIN); the rear 'whale tail' spoiler was re-profiled and raised slightly to make room for the intercooler and the spoiler was now infamously called the 'tea tray' spoiler by the enthusiasts. The suspension benefitted from new anti-roll bars, firmer shock absorbers and larger diameter rear torsion bars. Porsche also upgraded the brakes to units similar to those used on the 917 race car. While the increase in displacement and addition of an intercooler increased power output and torque, these changes also increased the weight of the vehicle, especially the engine, which contributed to a substantial change in the handling and character of the car compared to the earlier 3.0-litre models. Changing emissions regulations in Japan and the United States forced Porsche to withdraw the 930 from those markets in 1980. It however remained available in Canada. Envisioning the luxurious
928 gran turismo eventually replacing the 911 as the top of the Porsche model lineup, Fuhrmann cut back further development on the model, and it was not until his resignation that the company finally committed the financing to update the car's emissions systems, and recertify the 930 for sale in all markets. The 930 remained available in Europe, and for 1983 a at 5750 rpm and of torque at 4000 rpm In 1982,
TAG Heuer co-owner
Mansour Ojjeh commissioned Porsche to develop a road-legal version of the 935 race car. The final product was developed using a body shell of the 930 and fitting fabricated 935 body panels to it. The one-off also had the suspension and brakes shared with the 935 race car. Other special features of the car included special paintwork called Brilliant Red by the manufacturer, BBS wheels and the use of the 3.3-litre turbocharged flat-6 engine of the 934 race car. The car proved very popular among enthusiasts and prospective buyers began to demand a similar car as a factory offering. Porsche offered a "
Flachbau" ("flatnose" or "slantnose") 930 under the "Sonderwunschprogramm" (special order program) from 1986 model year, an otherwise normal 930 with a 935-style slantnose instead of the normal 911 front end with the replacement of the famous "bug eye" headlamps with pop-up units. Each
Flachbau unit was handcrafted by remodeling the front fenders (option code M505 for the US and M506 elsewhere). A limited number of units were produced due to the fact that the package commanded a high premium price, an initial premium of up to 60 per cent (highly individualised cars requiring even more) over the standard price. 948 units were built in total with 160 of them being imported to the US. The Flachbau units delivered in Europe usually featured the WLS performance kit. The flat nose greatly contributed to the aerodynamics of the car and enabled it to accelerate from 0–97 km/h in 4.85 seconds and attain a top speed of (figures with the performance kit). == Independently tested performance data ==