Porsche's 2018 911 GT2 RS Holds the Record for Most Powerful Production Six-Cylinder

Six-cylinder engines have long offered a balance of smoothness, efficiency, and performance in everything from sports cars to luxury sedans. But with forced induction and hybrid tech, some engineers have pushed six-cylinder power to supercar levels.

The current production champion is the 2018 Porsche 911 GT2 RS. 8-liter flat-six produces 690 horsepower and 553 lb-ft of torque, making it the most powerful six-cylinder engine ever fitted to a production car. 0:1, raising the rev limit to 7,200 rpm, and redesigning the intake manifold.

A water-spray system cools the intercoolers when intake air hits 122 degrees Fahrenheit, dropping temps by 20 degrees for consistent track performance.

Not far behind is Ford's 3.5-liter EcoBoost V6 in the 2016 GT supercar. Initially rated at 647 hp, final versions with gallery-cooled pistons and higher-energy ignition coils reached 660 hp and 550 lb-ft. The GT program was built for Le Mans, where the GTE won in 2016, exactly 50 years after the GT40's first victory.

With hybrid six-cylinders in hypercars, a 700-hp combustion-only six may soon appear. Porsche is reportedly working on a next-generation GT2, which could push the record higher. Sources: Porsche, Ford, Mecum Auctions.