Once the favored engine configuration for luxury and high-performance cars, the inline-six suffered a bit when the transverse (east-west) engine configuration became popular during the shift to front-wheel drive cars. The packaging benefits are obvious – no driveshaft or transmission intruding on passenger space or rear differential on cargo volume, plus turning the engine 90 degrees meant the front of the car could be shorter. But the inline-six is slowly, slowly crawling out of near-obsolescence, notably in Volvo, Jaguar-Land Rover, and Mercedes-Benz products. Add Mazda to that mix: An investor report first spotted by Jalopnik and confirmed by Mazda reveals that the company is developing a Skyactiv-X and Skyactiv-D inline-six that will be installed longitudinally (north-south) in a new "Large Architecture" platform.
Before reading any further, let's catch up on the Skyactiv-X and -D technologies. The former basically burns gasoline like diesel, providing some benefits and advantages of both types of combustion - here's an explainer on how that all works. We drove a prototype 2.0-liter Skyactiv-X 4-cylinder engine in a Mazda3 mule, too. And the Skyactiv-D series of engines is a comparatively typical turbodiesel. Mazda has a 2.2-liter turbodiesel inline-4 that has had a long and convoluted development and certification process, but is finally showing up in the 2019 CX-5.