964 RSR
With just 55 examples built, the 964 RSR was designed as a track-ready kit and would go on to reflect Porsche's dominance in production-based GT racing. Based on the 3.8 RS, the RSR's Type M64/04 engine featured lighter pistons, dual ignition, new intake manifolds with six individual butterflies, dry-sump lubrication and Bosch Electronic fuel injection produced 375hp and 284ft-lbs of torque (perhaps more depending on class restrictions). All that power is transmitted through an uprated 5-speed manual transaxle with 40% limited slip. Fully-adjustable competition Bilstein shocks and struts with adjustable anti-roll bars lowered the car by one and a half inches along with ABS brakes from the Turbo S, and 18-inch 3-piece Speedline wheels that are a half-inch wider than the RS meant the car had the hardware to put that power to the ground in a striking manner. Car and Driver tested one of the first RSR 3.8s to hit American shores and found it could hit 0-60mph in 3.7 seconds, complete the quarter-mile in 12.1 seconds at 116mph and max out at 181mph. At the end of the day, they found it was quicker than the F-40.
Crafted on the standard 964 assembly line the RSR's body shell would have its seems welded before being trucked to Wilfried Matter where it would see further treatment to increase their strength and prep them for the race track. There they would be fitted with a full roll cage with side intrusion protection (increasing its torsional rigidity) before returning the shells to Zuffenhausen for completion. The cockpit was entirely stripped of any amenities and featured a single Recaro racing seat, Shroth 6-point harness, and a fire suppression system. To reduce weight, all the windows were replaced with thinner glass, lightweight composite materials made up the front, and rear fascias and the door and front trunk lid were made of aluminum. The engine cover remained steel to better support the massive dual plane, fully-adjustable rear wing. In the frunk, Porsche source a British Premier Fuel Cell with a provision that allowed for through-the-hood refueling. In the event, the car is far from the pits, and in need of fuel, the driver can hit a red button in front of the gear selector that would operate a small fuel reserve system to help prevent the car from going dry.
Porsche designed these cars to allow its customers to dominate their competition straight from the factory. The RSR could even be ordered with a built-in pneumatic jack system and center-lock wheels to expedite pit stops. A completed car would come in at just 2,673lbs, well below the class average meaning teams could add ballasts were desired to meet the weight requirements and alter the cars weight distribution as needed.
The RSR was a winner right out of the gate, taking wins at the 1994 Spa 1,000km, a class win at Le Mans and at its first appearance in North America it swept the first four places in IMSA's GTU category. Production ran between April 1993 and December 1994 with 49 made plus one-preproduction test car and one factory racecar, plus a delayed run of four ars that have been omitted on many records, for a total of 55 units. Enough to satisfy FIA homologation requirements.
