Porsche 964 RS
964 Carrera RS. In hommage to the 1973 911 Carrera RS, Porsche used the same formula to produce a lightweight version of the Carrera 2 from the race-ready Cup car known simply as the Carrera RS. The Porsche Carrera RS, or 964 RS as it is more widely known started shipping in November 1991 as a 1992 model year car.
A primary objective for Porsche engineers was making the 964 RS as light as possible and in the end they were able to take out almost 300 pounds of weight. The bonnet was made out of aluminium, the side and rear windows were made from a lighter, thinner-gauge glass. Sound-insulating interior mats were removed, the front fog lamps were replaced with transparent covers and even the rust preventative undercoat was omitted. Porsche also removed the power steering, power windows, rear seats, electronically adjustable front seats and front armrests. The 964 RS was also fitted with lightweight magnesium Cup wheels. At 2706 pounds the 964 RS was 286 pounds lighter than the standard model.
The RS used an upgraded version (M64/03) of the M64 engine used in the 964 Carrera 2 and 4 (M64/01). Power was boosted by 10 horsepower from the new 3.6 liter boxer engine thanks to some magic by Porsche engineers. The pistons and cylinders were carefully selected and matched and the engine used rubber mounts in place of hydraulic mounts. It also had a lightweight single-mass flywheel that weighed 12 pounds. A lighter and simpler wiring harness was fitted and the ECU was reconfigured for higher octane fuel. Power went from 250 hp to 260 hp and torque increased from 229 ft/lbs to 240 ft/lbs.
The chassis was stiffened thanks to additional bracing and welding in key areas. The suspension on the Porsche Carrera RS was lowered by 40mm and made considerably stiffer with race-tuned shock absorbers. The front brakes comprised cross-drilled discs with four-piston fixed callipers as used on the 911 Turbo. The rear brakes were taken from the Carrera Cup race car. Performance wise, the 964 RS had the same power and top speed as the coupe on which it was based. It out-accelerated its donor car by a lot thanks to its lighter weight. 0 - 60 mph was over in just 5.1 seconds (0.5 second faster than the standard C2). On the track it was awesome and easily bested the C2. If you want to understand cars like the recent 911 R, a car like the 964 RS is a good place to start. The 964 Carrera RS was offered in three road legal versions. The first was a base option that offered no luxury at all, the second, a touring model, came with limited extras and the third was the N-GT (near-production GT).
964 RS America. The original 1973 Carrera RS was available in Europe but not in the USA. Porsche decided to build the 1993 Carrera RS both to European spec and a limited number in compliance with US regulations. These US spec cars were assigned the name “RS America”. The intent was to create a basic lightweight, no frills 911 with minimal luxury options.
The standard US Carrera 2 brakes, engine and gearbox were used. The RS weighed 2,945 pounds so it was almost 80 pounds lighter than a standard Carrera 2. Fitting the RS America with the M030 sport suspension package, which included the use of much of the running gear from the 911 C2 Turbo, led to higher performance limits. The Turbo's progressively wound coil springs, larger diameter front stabilizer bar, and upgraded shock absorbers were standard equipment for the RS America, as were 17” diameter C2 Turbo wheels. The RSA rims were 7” wide on the front and 8” wide on the rear (as opposed to the 7” wide front and 9” wide rear wheels of the C2 Turbo). It also got a very cool "whale tail" spoiler. In all, 701 cars were built as model year 1993 - 1994.
964 Carrera RS 3.8. Porsche wanted to race an RSR variant in the GT-category and the result was the car you see here, the Porsche 911 Carrera RS 3.8 (964). The RS 3.8 served as the homologation base for the 3.8 RSR for international competition. Basically the road going version of the Porsche 911 Carrera RSR 3.8 race cars it is still one of the most special Porsche cars ever made. Many of its features were borrowed from the 964 Carrera Cup cars. There were two versions; the Sport (or Lightweight) weighed about 10 percent less than the Touring version. Only 55 cars were ever made and they were all special ordered from the factory.
The RS 3.8 body is based on the 911 Turbo with the flared wheel arches. The RS 3.8 also had a more advanced aerodynamic profile thank the Turbo thanks to a deeper front spoiler and a large fixed bi-plane rear wing that was adjusted (and had a cool embossed "3.8" logo on its sides). It also got stronger chassis thanks to additional welding and strengthening throughout the shell. The RS 3.8 also got larger brakes and wheels.
Power for the RS 3.8 came from a 3.8 liter version of the M64 motor and was good for 300 bhp. The engine was bored out by 2 mm for a total of 3,746 cc and had a raft of other upgrades. The compression ratio was upped, it had a new intake system with individual throttle butterflies, bigger inlet and exhaust valves and even had its engine-management system software revised. It was known as the M64/04 type engine. An absolute legend.
964 C4 Lightweight. The rarest 964 RS variant was the awesome 964 C4 Lightweight. Known as the 964 Leichtbau it made use of surplus parts from 953 Paris-Dakar project and only 22 were ever made. The idea was to combine the 964 RS body with the more sophisticated all-wheel-drive system from the 959 while lowering weight.
The 964 C4 Lightweight was powered by the same 3.6 liter flat six as the normal 964 RS, but was fettled to produce 300 hp (the 964 RS made do with 260 hp). Porsche engineers freed the extra horsepower by removing the catalytic converters and mufflers. A special clutch and flywheels were mated to the car’s five-speed manual transmission. The coolest feature of the powertrain was the use of a Rally-style gearbox (thanks 953 Paris-Dakar project) that allowed the driver to adjust the torque split of the centre and rear differentials via two rotary controls on the centre console.
The RS Lightweight earned its name thanks it's scant 1098 kg weight. The car was based on the M003-optioned RS shell albeit now with four-wheel drive. The combined use of an aluminum front lid, aluminum doors, Plexiglas side windows and a fiberglass rear engine lid as well as the removal of many niceties definitely contributed. Porsche did more than simply replace body panels with aluminum and fiberglass and delete sound insulation and carpeting however. The car was race-ready with a seam-welded tub and fixed windows with sliding panels. One visual clue to the identity was in the re-adoption of the external oil filler, just in front of the right rear wing.
From a performance perspective the 964 C4 Lightweight was unique. Thanks to its 2,400 pound weight and very short gearing it was only able to hit a 125 mph top speed, but acceleration was absurdly fast. Official Porsche numbers quite 0 - 60 mph in 4.5 seconds but most testing showed the car was actually able to do 0 - 60 mph in only 3.9 second times.
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