Porsche 911S/RSR Carrera
Almost since the 1964 advent of the Type 901 (swiftly changed to the immortal Type 911 at Peugeot’s insistence), Porsche have been building small batches of competition versions for their race-oriented customers. Starting with the 911R of 1967, a definite effort was made to not only lighten the car as much as possible, but to increase the power. The "R" put out some 210 bhp from what was essentially a 906 power unit although still of just 2-liter capacity. The "R" was followed by batches of 2.3 and 2.5 liter competition 911s with the 2.4 S/T sandwiched in between. All achieved considerable success in their class, 2.5S’s fitting perfectly into the newly introduced GTU class of the new IMSA-organized races for GT cars.
By 1972, Porsche saw, with the World-wide recession as fuel prices rose dramatically, that a market existed for a faster road-going 911 than the then-current 2.4 liter "S". Where motor sport was concerned, Porsche’s engineers also saw that a more powerful 911 would fit nicely into the forthcoming Group 4 class that was destined to supplant the Sports-Racing cars in International competition.
To this end, Porsche enlarged the 2.4 liter flat-six engine (although still retaining its magnesium crankcase) to 2.7 liters and thus the immortal RS 2.7 Carrera was born. There were some small changes made to the suspension department also plus wider wheels and tires but Porsche were astonished when the first 500 cars were ordered straight from the motor show stand. 500 was all that Porsche had to build to homologate the RS as a base for the much more powerful RSR Carrera (Renn Sport Rennen-Motor Sport Racer) which they had planned. However, the factory eventually built a total of 1,580 RS 2.7s in both lightweight and Touring form. Ironically, the so-called "lightweight" which collectors desire today is little more than a Touring model with the trim removed!
So, for 1973, the Porsche factory built the new RSR. This featured cylinder barrels and high-compression pistons of 2,808 cc, twin-plug ignition, bigger fuel injection pump, wider wheels and tires and flared out wheel arches to cover them. A 10,000 rpm tachometer, stripped interior and a rollbar completed the picture. Power was now rated at 300 bhp at 8,000 rpm.
The RSR had a dream competition. Two were entered in the 1973 Daytona 24-Hours, one by Roger Penske for Mark Donohue and George Follmer and one for the Brumos Racing team from Jacksonville to be driven by Peter Gregg and Hurley Haywood. Although the Penske car had pulled out a lead after 18 hours of racing, a piston failed and they were out. The much fancied sports-prototypes of Alfa Romeo and Matra had all dropped out. When the flag fell after 24 hours of hard racing, Peter Gregg and Hurley Haywood were the winners. One month later, another ‘customer’ RSR won the Sebring 12-Hour race and yet another factory-entered RSR won the last-ever Targa Florio besides good placings and class wins in the major international events. The RSR was an ideal weapon for IMSA competitors: strong, light and easily maintained. It was an ideal ‘customer’ car and dominated that series. Although cars with bigger engines such as the Chevrolet Corvette and Camaro were faster (although not by much!), they required more stops for fuel in the endurance races which IMSA specialized in. RSRs won the IMSA Championship for three years straight, 1973–1975, always driven by the Brumos pairing of Peter Gregg and Hurley Haywood.
For 1974, Porsche uprated the RSR, introducing a stronger aluminum crankcase, bigger barrels and pistons of 3-litres, and slide-valve fuel injection. Wheels and tire width now went to 10.5-inch front and 14-inch rear with correspondingly enlarged fiberglass fenders to accommodate them. The huge brakes from the Porsche 917 were now fitted and the RSR was even faster around the track. In Europe, several cars were used by the factory to develop all kinds of aerodynamic "tweaks", putting them into Group 5 where they had no real chance of outright success but still allowing Porsche’s engineers to prepare for the forthcoming turbocharged variants, the 934 and 935. Where customer racing in Europe was concerned, it was the same story as in the USA. RSRs won the prestigious European GT Championship as well as a host of national championships including the German National Championship, which eventually overwhelmed the European equivalent and later on became almost as big as the World Championship.
The RSR soldiered on for many years past 1976 when the newer turbocharged 934s and 935s were introduced. Such were the numbers competing in IMSA that the entrants lobbied to keep out the turbocharged cars which John Bishop managed until almost through the 1976 season. As late as 1977, an RSR won the Daytona 24-Hours, going out in triumph almost where it came in, in international events. The RSR Carrera became a favorite again when it became the ideal car with which to compete in the new GTO class of IMSA from 1978 until 1981 when the rules were changed to allow in turbocharged 934s.
There have been few more successful race cars than the Porsche RSR Carrera. Essentially a developed street car, it embodied all the successful attributes of a good race car; sufficient power, good handling, brakes, reliability and strength. What’s more, it was there in sufficient numbers when the customers needed them.
