Porsche made its first and most significant changes to the 930 for 1978 model year, enlarging the engine bore by 2 mm (0.08 in) to a total displacement of 3,299 cc (3.3 L; 201.3 cu in) and adding an air-to-air intercooler. The suspension benefitted from new anti-roll bars, firmer shocks and larger diameter rear torsion bars. While the increase in displacement increased power output and torque, it also increased the weight of the vehicle, which contributed to a substantial change in the handling and character of the car compared to the Earlier 3.0-Litre Models.
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. 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 the Carrera RS 3.0, thus creating what Porsche internally dubbed as the 930. Total power output from the engine was 260 bhp and 254 ft lbs of torque.
Only 50 units made. The 911 Turbo Limited Edition comes equipped with the 330 bhp power unit normally only available in the 911 Turbo with Sport Equipment. In addition, the fitment of a limited slip differential as standard ensures the the increased engine performance can be used to it’s fullest extent. This Limited Edition also adopts the rear wheel air intakes of the Sport Equipment version. Essentially an SE without a slantnose front.
Just 50 ‘C16’ cars were manufactured for the UK-market, initially equipped with an uprated engine of 330bhp (from 300) mated to a 4-speed transmission. However, at the end of 1988, the uprated 5-Speed G50 gearbox was introduced, dramatically easing the peaks in power delivery by reducing the effects of ‘turbo-lag’. The factory SE also benefited from a dual-exit exhaust system, limited-slip differential, heated front seats and a sunroof.
Slantnosed and based on that of the 935 racecars, with pop-up headlamps. The front spoiler was made deeper in order to accommodate the extra oil cooler, while intakes in the rear wings fed air to the brakes. The larger turbocharger and four-outlet exhaust gave 30bhp of extra power. Porsche began their “special order program” offering a Flachbau option (Slantnose) for the 930 in very limited production. All of this at a cost of nearly 2 times the standard 930S.
The 935/78 was the ultimate expression of the 911 factory race car before Porsche officially withdrew from motor sport. Raced under the Group 5 silhouette series, great liberties were taken with the design and the result was nicknamed ‘Moby Dick’ for its large size and huge overhangs. The 935/78 was built under Porsche's Chief Racing by Norbert Singer for high speeds at Le Mans. Due to the advanced shape of the car 227 mph or 366 km/h was possible.
The 935/77 was a result of relaxed rules and the car got a completely new suspension. The mirrors were incorporated into the front fenders and the rear window had a new angle. The 935/77 was visually very pleasing. While the 935/76 had a single turbocharger, the 2.85-litre engine of the 935/77 had two turbochargers. There was also a "baby" 935/77 built with a smaller 1.4-litre turbocharged engine to compete in the national German DRM series under 2 liter class.
The Group 4 racer based on the 911 Turbo (930) was called 934 and the Group 5 Porsche was called 935. The first version of the 935 looked similar to the 911 Carrera RSR. The first customers for 935 were Martini Racing and Kremer Racing. The Martini car was a full factory development, while Kremer made its own enhancements already before the first race. By 1977, the 935 was sold as a customer car for these series to race against cars like the BMW CSL.
In 1967 Porsche prepared a small number of 934 Porsches with 935 Group 5 parts for the Trans-Am and IMSA GTO series. In the end, the 934/5 dominated the Trans-Am series by taking to top five positions in the championship. Ludwig Heimrath became the 1977 Trans-Am champion in his 934/5 by protesting Peter Gregg's highly modified car. Together they humbled the Corvette C3s and the Group 44 Jaguar XJS.
Using the 930 Turbo as a basis, Porsche built the 934 for Group 4 GT racing. It replaced the outgoing Carrera RSR while winning GT Championships in Europe and performing very well in America for Trans Am. Porsche built the 934 from a standard 930 bodyshell and production rear spoiler, but almost nothing else was left alone. The suspension was converted to solid mounts and nylon bushings with adjustable anti-roll bars.