For the more expensive Millenia S, Mazda indulged its affinity for unique engine technologies, equipping this model with a 2.3 litre Miller Cycle V6 engine that despite its smaller displacement, produced 210 horsepower.
Miller Cycle Engine. Click image to enlarge
Patented by Ralph Miller in the 1940s, the Miller Cycle engine differs little from a conventional Otto-cycle engine except for two key things. The Miller Cycle relies on a supercharger and uses unconventional valve timing that keeps the intake valve open during the compression stroke so that the piston is pushing against the pressure from the supercharger instead of the cylinder walls. The result is an engine that’s more efficient than a traditional Otto cycle powerplant. Both engines were mated to a four-speed automatic transmission.
That efficiency shows through in the Millenia’s fuel economy numbers. Despite the difference in power output, both engines returned the same figures throughout the Millenia’s model run. Natural Resources Canada rated the car’s fuel consumption at 12.2 L/100 km in city driving, and 8.3 L/100 km on the highway.