Mazda's 4.0l W12 -- This engine was shown at the 1989 Tokyo motor and was intended for Mazda's Amati luxury brand that never materialized. The engine was limited to 280hp and 274lb-ft of torque because of the Japan's gentleman's agreement, but keeping in tradition of Mazda's unique engine design history (rotary, Miller cycle, etc) they decided to go with the W-configuration for their 12 cylinder. While the block is aluminum, the rest of the engine is mostly magnesium. Arguably the most interesting design feature were the ceramic cylinders and aluminum-ceramic valves. Very ground breaking for the time.
