Runge Hetzer: The Porsche Flat-Eight Engine Never Built

For decades, Porsche toyed with the idea of an air-cooled flat-eight engine. It hinted at one in its 1960s Le Mans prototypes and revisited the concept over the decades that followed, yet it never took the final step. The result remained confined to engineering ambitions and track-side roar - never reaching the road.

The Porsche flat-eight that never reached production

Now, the engine Porsche never dared to build is being brought to life by a small American company: Runge Cars. Called the Hetzer, it is a 5.3-litre air-cooled flat-eight with four camshafts and 32 valves. It is a piece of mechanical art that poses a compelling question: what might have happened if Porsche had found the courage to build it?

The Hetzer has been created alongside British firm Swindon Powertrain and specialist Sol Snyderman, a legendary name in the world of air-cooled engines. There is also a detail guaranteed to please purists: the Hetzer fits directly into classic 911 chassis. Its redline stands at 9000 rpm - because an engine like this was never intended to breathe slowly.

Hetzer flat-eight power for the Runge R3

This flat-eight will power the Runge R3, a hand-built sports car weighing 780 kg and fitted with a six-speed manual gearbox. It has been conceived to deliver “the most visceral analogue driving experience available today”, in the words of founder Christopher Runge.

The first three engines will be made exclusively for the brand. Runge will then begin accepting orders - perhaps the most symbolic element of this story. At a time when the industry is striving to become quiet and predictable, some still have the audacity to reignite the metallic sound of combustion.

Ultimately, it is not merely an engine. It is tangible proof of what Porsche envisioned but never had the courage to build.