Porsche 964 RS Vs Porsche C4 Lightweight – Who’s Will Win The Lightweight Crown?

A s introductions to a new track go, this undoubtedly registers at the ‘surreal’ end of the spectrum. I’m no stranger to learning unfamiliar circuits, but I don’t normally initiate myself to new surroundings quite like this. At the wheel of a 964 Carrera RS, I’m familiarising myself with Botniaring’s nine distinct turns, all the while battling 1.62 miles of damp Finnish Tarmac soaked an hour or so earlier by an unseasonably heavy rainstorm. As if that wasn’t challenging enough, I’m attempting to keep up the pace with one of Weissach’s racing legends, Jürgen Barth.

Yes, that Jürgen Barth, the man who has stood on all three steps of the La Sarthe podium, topped of by a victory in the 1977 24 Hours of Le Mans. Did I mention that Jürgen is driving a nearpriceless 964 Carrera 4 Lightweight, a car that he devised while heading up Porsche’s customer motorsport division? No? Well he is, and the advantage of four-wheel drive traction (and his obvious surplus of talent) is making my job entertainingly difficult. I said it was surreal.

Thankfully, the 964 Carrera RS – as I found out on the Peak District’s roads in issue 128 – is the friendliest Rennsport partner a 911 enthusiast could ask for, one of the key factors behind its current resurgence in the eyes of Porsche collectors. Unlike later GT3-prefi xed RSs, the 3.6-litre 964 is no high horsepower animal, meaning that I’m left to revel in the delicious chassis devised by Roland Kussmaul and co at the turn of the 1990s. More on that later though. The Porsche 964 RS – the fi rst Rennsport to get a large production run since the iconic Carrera 2.7 RS – was, like many of Weissach’s greatest road car creations, born out of the necessity to go racing. In 1988, after a six-year stint at BMW, Ulrich Bez returned to Weissach as technical director after Helmuth Bott’s decision to retire.

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Porsche 964 RS

At the time, Porsche’s Cup series in Germany and France were using the front-engined 944 Turbo but, with the 964 generation of 911 due to debut at the end of 1989, Bez believed that the one-make championships were the best shop window for the new neunelfer. Based on the newly launched Carrera 2, research director Helmut Flegel devised the specification of the 964 Cup car before the build process was entrusted to Kussmaul, who oversaw the seam welding of the body shells and the fitment of the Matter roll cages. Contrary to popular belief, the Cup cars’ engines weren’t blueprinted. Instead, Kussmaul simply tested a selection of M64/03 engines on a dynamometer, before choosing those with the best power outputs. With Barth in charge of the commercial side, the 964 Cup cars proved popular, debuting in 1990 with Olaf Manthey winning the inaugural Carrera Cup Germany to feature 911s. However, in order to be homologated for international competition, the FIA required a number of road cars to be built as proof of the Cup car’s production credentials. Step forward – in numerous ‘flavours’ – the 964 Carrera RS.

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Featuring the same seam-welded shell and 3.6-litre air-cooled flat six (boosted to 260bhp by a tweaked ECU as the Cup car), even the touring version of Rennsport inherited the Cup car’s motorsport DNA. Compared to the standard Carrera 2, which hit the scales at a portly 1,350 kilograms, Kussmaul’s team managed to diet the Rennsport version down to a sprightlier 1,220 kilograms in Lightweight trim. An aluminium bonnet, three millimetre side and rear glass, and plastic 92-litre fuel tank all helped to reduce the RS’s dry weight, as did the pretty teardrop wing mirrors borrowed from the Turbo. Perhaps the most famous mass reduction measures though were the iconic ‘Cup 1’ alloy wheels, forged from magnesium. An instant icon, they were later ofered as an option on base Carreras (albeit in a heavier aluminium alloy guise). While a focus on weight reduction has always been a central tenet behind the Rennsport philosophy, Weissach’s engineers did not forget to upgrade a number of the 964 RS’s mechanical components either. The majority of examples were fitted with a single-mass flywheel, aiding the M64/03’s throttle response, while the standard Carrera 2’s Getrag-built ‘G50’ was bestowed with diferent ratios and stronger synchromeshes.

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