This is the fourth in our series of brief articles highlighting the Porsche marque, and continues the story of the Model 911.
Born from Porsche's endless obsession with racing and performance, the Porsche 911 Carrera RS 2.7 was developed to compete in the Group 4 GT class of the newly established European GT Championship in 1973.
During the 1970 racing season, the World Sportscar Championship, which had been dominated by Porsche's 4.5L Model 917 for several years, announced that Group 5 Sports Cars would be limited to 3.0L engines beginning in 1973. Porsche could continue to race in the series; however, it would require developing, designing and building an all-new replacement for the Model 917 from the ground-up. Instead, attention was turned to the new European GT Championship series and it's Group 4 GT Class for which Porsche's Model 911 was already eligible.
The 2.4L Model 911S had already proven it's racing pedigree with success in events such as the Rally Monte Carlo and the Tour de France. It was the obvious choice for further development for the European Championship series. Porsche lined up the Ferrari 365 GTB Daytona 'Competizione' in it's crosshairs and set out to design a lighter, more powerful version of the Model 911S that was capable of out-performing the Daytona on the track. Considering the Ferrari's displacement was nearly twice that of the largest Model 911 engine at the time it was obvious that Porsche was going to have to dig deep.
Initially, the design team focused on shaving weight and increasing the power output. By increasing the bore of the 2.4L flat-6 to 90mm, Porsche was able to pound another 20 bhp out of the now 2.7L engine. This brought the grand total to 210 raging horses, displacing a whopping 2687 cc's. Weight was reduced by utilizing thinner gauge steel and/or fiberglass on as many body applications as possible, along with using thinner, lighter glass for windows and windshields. The new Carrera RS 2.7 was capable of a top speed of 158 mph and could accelerate from a standstill to 62 mph in just a touch over 5 seconds. With these impressive stats there were no worries about reaching the homologation requirements of 500 units - in fact, the 500 units were sold out immediately. An additional 1080 were subsequently built, bringing the total to 1580 cars produced between April of 1972 and July of 1973.
Aside from the mechanical upgrades of the Model 911 Carrera RS 2.7, the cars were fitted with a revised and stiffened suspension, and larger brakes. Wider rear fenders were needed to accommodate the wider rear tires that helped to put all that power to the road. The now iconic "ducktail" rear spoiler also made its appearance. Nine protoypes were built prior to production, a few of which have been fully restored and are still roadworthy (and extremely valuable) today. They can be fairly easily identified by their lack of the "ducktail" - a hallmark that was reserved for the production units.
The rules of the GT Championship allowed for select modifications to be made to the cars that raced. These modifications did not have to be incorporated into the production models. Based on these rules, Porsche developed a beefier racing counterpart to the Carrera RS 2.7 - the Model 911 Carrera RSR 2.8. The Carrera RSR 2.8 hammered out almost 100 bhp more than it's domesticated bretheren thanks to a 2mm larger bore and a compression ratio of 10.5 : 1. The increase in power justified even wider rear wheels with wider fenders to accommodate them. The stock brakes were replaced with vented and cross-drilled discs to reign it all in when necessary. The RSR 2.8 lived up to it's high expectations winning an impressive six out of nine rounds of the 1973 European GT Championship.
During the 1973 season a prototype version of the RSR 2.8, featuring even further modifications, was campaigned to the public. The additional modifications made it ineligible to compete according to the Group 4 class rules of the European GT Championship. To rectify the situation, Porsche fitted the upgrades to a new series of road cars, the Model 911 Carrera RS 3.0, met homologation requirements, developed the RSR 3.0 racing counterpart and went on to compete in the European GT Championship in 1974 - continuing the legacy of dominance established by the RSR 2.8 and paving the way for the turbocharged beasts that were lurking just around the corner.
911 RS and RSR examples from this period border on the ultimate in desirability as far as classic 911 models are concerned, with stratospherically high values well into six figures. Classic insurance with a proper Agreed Value - and an understanding of the extraordinary measures that will be needed to repair one of these rolling works of art - is essential.