What was the horsepower output of the Porsche 959?

The Porsche 959 produced 450 hp.

Introduced as a Group B technology demonstrator, the 959 used a 2.85-liter twin-turbocharged flat-six derived from Porsche’s successful racing-engine work. Its sophisticated all-wheel-drive system, electronically controlled suspension, and adjustable drivetrain made it far more advanced than an ordinary 1980s sports car.

The 959 was built primarily to satisfy FIA homologation rules, which required manufacturers to produce a road-going batch before competing. Porsche developed both competition and road versions, and the production car became one of the fastest street-legal automobiles of its era, with a quoted top speed of about 197 mph.

A common mix-up involves the 959 S, a lighter and more powerful variant that produced approximately 515 hp. The standard 959 is generally listed at 450 PS or 450 hp in reference material; PS is a metric horsepower unit, so the exact mechanical-horsepower conversion is slightly lower. Trivia references conventionally use the rounded 450-hp figure.