Ferociously quick, the 924 Carrera GTR was the strongest and fastest—barring only the GTR Le Mans and GTP—of Porsche’s first-generation water-cooled racing cars.

In 1979, Porsche began developing its 924 Turbo as a Group 4 GT entry for the 1980 24 Hours of Le Mans.

The new coupe was fitted with a full alloy roll cage and an additional cross-brace beneath the hood.

Body panels included aluminum, lightweight urethane and fiberglass.

Disc brakes and axles came from the 935 parts bin; a larger intercooler was fitted in the nose; an uprated dog-leg five-speed transmission with limited-slip and its own cooler mounted at the rear gave the chassis exceptional balance.

The suspension was fully adjustable, with titanium springs and Bilstein coil-overs front and rear.

The dry-sump 2.0-liter inline four developed a startling 375 horsepower with almost 300 pound-feet of torque, giving the 2,050-pound GTR brilliant a 180-mph top speed.

After a trio of 924s made a successful debut in 1980, Por...