Porsche 911 Carrera RSR Turbo 2.1 (AUTOart 1:18)

In 1974 Porsche started experimenting with turbocharging the RSR. This sole 2.1 liter prototype about produce 500 bhp and is easily identified by its extended rear wing.

Carrera RS (1973 and 1974)

A 1973 Porsche 911 Carrera RS

These models, valued by collectors, are considered by many to be the greatest classic 911s all-time. RS stands for Rennsport in German, meaning "racing sport". 

The Carrera name was reintroduced from the 356 Carrera which had itself been named after Porsche's victories in the Carrera Panamericana races in Mexico in the 1950s. The RS was built so that Porsche could enter racing formulae that demanded that a certain minimum number of production cars were made. Compared with a standard 911S, the Carrera 2.7 RS had a larger engine (2687 cc) developing 210 PS (150 kW; 210 hp) with MFI, revised and stiffened suspension, a "ducktail" rear spoiler, larger brakes, wider rear wheels and rear wings. 

In RS Touring form it weighed 1075 kg (2370 lb), in Sport Lightweight form it was about 100 kg (220 lb) lighter, the saving coming from the thin-gauge steel used for parts of the bodyshell and also the use of thinner glass. In total, 1580 were made, comfortably exceeding the 500 that had to be made to qualify for the vital FIA Group 4 class. 49 Carrera RS cars were built with 2808 cc engines producing 300 PS (221 kW).

In 1974, Porsche created the Carrera RS 3.0 with K-Jetronic Bosch fuel injection producing 230 PS (169 kW).It was almost twice as expensive as the 2.7 RS but offered a fair amount of racing capability for that price. The chassis was largely similar to that of the 1973 Carrera RSR and the brake system was from the Porsche 917. The use of thin metal plate panels and a spartan interior enabled the shipping weight to be reduced to around 900 kg (1984 lb).

Porsche RSR with Gijs van Lennep at the Nürburgring 1974

1976 Porsche 911 2.7

The Carrera RSR 3.0 and Carrera RSR Turbo (its 2.1 L engine due to a 1.4x equivalency formula) were made in tiny numbers for racing. The turbo car came second at the 24 Hours of Le Mans in 1974, a significant event in that its engine would form the basis of many future Porsche attempts in sportscar racing, and can be regarded as the start of its commitment to turbocharging.

Text Source: Wikipedia

Photo Graphic: Jason