1991 Porsche 911 Turbo S-2

The first generation of the Porsche 911 Turbo was introduced in 1975. The second generation appeared in 1989 and was based on the newly designed platform with the internal designation of 964. It was an evolved version of its progenitor that corrected two previously problematic areas with the 930 through improved suspension dynamics and reduction of throttle lag. Three primary changes were made to correct the notorious throttle lag of the first-generation car, with the installation of a larger turbocharger, a reduction in boost pressure from 11.6 PSI to 10.2 PSI, and the installation of a larger intercooler. The result was a 33 horsepower increase in power - from 282 to 315 - and dramatically improved drivability. A dramatic suspension change-out from the traditional torsion-bar arrangement to that of a coil-over design resolved the handling issues. Steering and handling became more predictable and helped mitigate sudden oversteer issues of the 1st gen.

Production of the 964 Turbos reached a modest total of 3,660 examples.

Porsche introduced a lightweight version, the Turbo S Leichtbau (TSL) as it came to be known, at the Geneva Auto Show in 1992. It had the character of the Carrera RS and was based on the Brumos Racing Turbo S2 that Hurley Haywood won IMSA Supercar Championships in 1991 and 1992. It employed weight-saving measures used in the Carrera RS, including the lack of excessive sound-deadening and undercoating, and eliminated conveniences such as power windows, power steering, air-conditioning, and rear seats. Fiberglass-reinforced carbon composite materials were used for the rear spoiler, front lid, and doors. Other weight-saving measures included thinner glass, bucket seats, and RS door panels. Compared to the standard Turbo, the Leichtbau weighed 2,844 lbs, a saving of about 430 lbs.

The Type M30/69 SL engine received new fuel injectors, greater boost pressure, and aggressive camshafts, helping bring power to 381 bhp at 6,000 RPM, an increase of 61 horsepower over the 3.3 Turbo. The ride height was lowered by 40 mm, the suspension was tuned to Carrera RS settings, and an aluminum front brace was installed to provide stable handling. The bodyshell was reinforced and seam-welded, the brakes were upgraded, and 18-inch Speedline modular wheels with Dunlop Sport ZR-rated tires were installed.

Visual changes included the 959-style fender vents, unique rear spoiler, and front bumper intakes.

Haywood's victory in the IMSA Supercar series was impressive especially considering that Brumos Porsche changes hands in 1990 and the new owners had just re-activated Brumos Racing. The mandate was 'we race what we sell.' The Brumos team fielded two 964 Turbo cars for the 1991 season wearing race numbers 58 and 59. Haywood drove the number 59 car while Hans Stuck drove the number 58. When Stuck was unable to drive number 58 due to other obligations, the driving duties were handled by Joe Varde.

During the season, the three drivers delivered 100% top-ten finishes, earning Brumos the first Superchar championship for Porsche. Haywood was awarded the driver's championship with three victories (Portland, Watkins Glen from the pole, and Road America). Brumos won the team and driver championship the following year. Stuck added two wins, and Walter Rohrl contributed second- and third-place points. For the second year in a row, the Brumos drivers placed 100% in the top ten. There nine podium finishes included four outright victories.

1993 was Brumos' last season the Supercar series and they finished the season with their third consecutive championship. Stuck and Haywood followed up in 1994 by winning the IMSA GT Endurance Cup driver's championship.

The Brumos team's 964 Turbo Supercar was powered by an air-cooled turbocharged flat-6 with a 201.3 cubic-inch displacement. It had 2 valves per cylinder, single overhead camshafts, a 100mm bore and a 76mm stroke. The induction was handled by a K-Jetronic fuel injection system which helped produce 320 horsepower at 5,750 RPM. The top speed was approximately 170 mph. The engine was backed by a five-speed manual gearbox and disc brakes with ABS were at all four corners. The cars had a wheelbase of 89.4 inches and weighed 3241 pounds.

by Daniel Vaughan | May 2020