Porsche by Dennis Adler

Author:Dennis Adler
Language: eng
Format: epub
Publisher: Skyhorse Publishing
Published: 2014-01-01T05:00:00+00:00

Bobby Unser leads Peter Revson in the 1974 IROC race at Riverside, California.

RSR engines had aluminum pistons, cylinders, and cylinder heads; higher lift camshafts; slide throttles; and a breakerless capacity discharge twin-ignition system. The RSR-tuned engines had a bore × stroke of 95 millimeters (3.75 inches) × 70.4 millimeters (2.8 inches) and displacement of 2,992 cubic centimeters, so their compression ratio was raised to 10.3:1. Output was nominally 320 horsepower at 8,000 revolutions per minute, but ranged 10 horsepower above and below that estimate, depending on the individual engines.

The Competition Department supplied all the essentials in the stripped-down racing cockpit of the Carrera. The interior was furnished with a special Recaro racing seat with a high squab and headrest, full harness restraint, built-in roll bar, and a fire extinguishing system. The driver faced a stock 911-style instrument panel equipped with a 10,000-revolutions-per-minute tachometer and a 300 kilometers-per-hour speedometer. The cars were fitted with center lock hubs carrying racing pattern wheels of 10.5-inch and 14-inch front and rear widths covered by almost comic-book-proportion fenders made of fiberglass.

The overwide fenders gave the RSR 3.0 an incredibly aggressive stance. At the rear, the flares were blended into the body but punctured at both their leading and trailing surfaces by air vents to cool the rear brakes. The wider front fenders were smoothly flared into the nose panels, but at their rear edges, just at the door cut line, they simply stopped, leaving a huge rear-facing opening to vent air. This break with conventional fender design looked, and was, so functional that other builders of modified production cars immediately adopted it.

The racing modifications—interior, engine, suspension, body work, wheels, and tires—added a hefty $6,000 to the price of a 1974 Carrera RS 3.0, which at that time was already the highest priced Porsche 911 ever at $25,000. Max Hoffman would have fainted dead away.

As for the stature of the Carrera RSR in the eyes of the racing community, Mark Donohue summed it up quite nicely after testing an RSR prototype at the Paul Ricard Circuit in France. Donohue, who was never long on words, said, “The Carrera is, without a doubt, the very best off-the-shelf production race car available at any price.”

On Donohue’s advice, Roger Penske ordered fifteen Carreras to use for the 1974 International Race of Champions (IROC). Mechanically, the cars were a combination of the RS and RSR models, but they were built to look more like production 911s and thus were more readily identifiable to spectators as Porsche road cars. Each was tested on Porsche’s Weissach skid pad and tuned to give comparable performance before being shipped to Penske. All the engines were set up to deliver around 316 horsepower. If there was any advantage a driver could gain in the IROC series, it was in knowing how to drive a 911. As luck would have it, at the end of the season it was Donohue who won the IROC title, besting a field that included such racing luminaries as Emerson Fittipaldi, Denis Hulme, A.

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