Many car enthusiasts have long been pining for Mazda to bring back its quirky rotary engine, but the Japanese automaker may be about to put something even more surprising under the hood of one of its cars. Tucked inside of the company’s latest quarterly earnings report is a slide that reveals it is working on its first inline-six-cylinder motor.

Two of them, actually. A Skyactiv-X gasoline version and a Skyactiv-D diesel.

The Mazda Vision Coupe concept has the kind of hood a straight-6 would be right at home under. (Mazda)

Straight-sixes are prized for their perfectly balanced cylinder firing order, which makes them as turbine- or rotary-smooth as a piston engine can be. Although the layout fell out of favor for many years, due in part to the packaging challenge presented by their length, BMW has long been carrying its flag and was recently rejoined by Mercedes-Benz and Jaguar Land Rover. The Skyactiv-X adds a twist, however, because it denotes a new Mazda technology that uses both spark and compression ignition in gasoline engines.

(Mazda)

And it gets even better. First highlighted by Jalopnik, the page also mentions a new large car platform, which would likely spawn a rear wheel drive sedan like the recent Mazda Vison Coupe concept, which has an epic hood that looks like it could easily accommodate a straight-six. Mazda has been shifting its products upmarket in recent years, and this would fit that new philosophy.

No timeline or details were mentioned for any of this, however, so a new rotary may still beat it all to showrooms. Mazda last year confirmed that it will have one in production next year, just not in a sports car like the RX-7 or RX-8 it one used to be featured in. Instead, it will serve as a range-extending generator in a yet to be revealed plug-in hybrid model.

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