Runge Cars, from Minnesota, is developing a new engine with assistance from Swindon Powertrain. CarBuzz claims it is an air-cooled, eight-cylinder mill designed to power an ultralight supercar known only as the R3.
Based on the 3D renderings, the vehicle in question is a mid-engined coupe with Le Mans-inspired looks, gullwing doors and an unmistakable Porsche aesthetic. It looks like a track-only model, but rear view mirrors and turn indicators suggest otherwise. The only parameter disclosed so far is the weight: the whole car is expected to tip the scales at 780 kilograms (1,720 lbs).
That sounds especially impressive if you factor in the Hetzer flat-8 engine sitting under the hood. The mill is being designed from the ground up with 5.3 liters of displacement, four valves per cylinder (32 total) and a 12:1 compression ratio. It will freely rev up to 9,000 RPM and only redline at 10,000. A six-speed manual transmission will handle the torque.
The first three engines made will power a trio of Runge R3, but all subsequently produced units will be available for installing on classic air-cooled Porsches, the tuner claims. More details should emerge in late 2025.
