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January 17, 2024

Mazda To Bring Back Rotary Engine Development Group

At the Tokyo Auto Salon, most of the attention over at Mazda went straight to their plans of reviving an in-house tuner in the form of Mazda Spirit Racing. And while that’s certainly good news to Mazda fans and enthusiasts, there’s an even better story: the brand’s decision to build a new rotary-powered sportscar.

To recall, Mazda brought the rotary engine back under the hood of MX-30 e-Skyactiv-R EV. Although it’s not exactly the body style most have hoped to see the rotary engine being used, the fact that production of the engine re-started more than a decade after it was discontinued is no small feat.

Compared to the RX-8 and even the legendary RX-7 before it, the MX-30 e-Skyactiv R-EV is a series plug-in hybrid electric vehicle (think Kicks e-Power with a plug). This means, the rotary engine acts simply as a generator providing electricity to the 170 horsepower, 260 Nm electric motor and charging the on-board 17.8-kWh battery.

Selected for being compact and lightweight, the new 8C rotary engine is a single-rotor unit with a 120 mm rotor radius and 76 mm rotor width. With an overall width of less than 840 mm, it fits under the hood with no changes to the MX-30’s body frame.

At 830cc, it’s the largest displacement rotor ever. It makes 71 horsepower at 4,500 rpm and 112 Nm of torque at 4,500 rpm. It is also over 15 kilograms lighter than the previous Renesis used in the RX-8. It uses direct fuel injection, a high compression ratio (11.9:1), and Exhaust Gas Recirculation (EGR) for improved efficiency and emissions. The apex seal thickness—a common issue with earlier rotary engines—has been increased to 2.5 mm and the sides treated by cermet (a mixture of metals and ceramics) spraying to reduce friction resistance and wear.

At the Tokyo Auto Salon, Mazda’s President and CEO Katsuhiro Moro says they want to continue to develop the rotary engine and put it into a production sportscar. He points to the Mazda Iconic SP Concept which shows that sportscars can change and evolve to fit the times. A fun-to-drive car can also be environmentally-friendly.

“The [Mazda Iconic SP Concept’s] unique system uses a two-rotary engine as a generator that can be used as a battery electric vehicle (BEV). It can be driven freely without worrying about cruising range. The system horsepower is 370 horsepower and the power-to-weight ratio is less than 4 kilograms [3.9 to be exact for the 1,450-kilogram sportscar], making it a first-class product. This concept car received a lot of support and encouragement,” said Moro-san.

Now comes the clincher. In Moro-san’s own words:

“With everyone’s support, we will launch a rotary engine development group on February 1 to move closer to this dream [of producing the Mazda Iconic SP Concept.] To make breakthroughs in the challenges facing the carbon-neutral era, rotary engine engineers which have acquired a broad technical perspective, engineers who are working on our current engine technology, and masters of our model-based development will reunite. It’s not that easy, but I hope we can take a step forward into a new chapter of never-ending challenges.”


  1. Will Mazda's new rotary engine only work as a range extender or an engine that will actually move the car?

    1. The 8C fitted into the MX-30 is basically a generator.

      The plans are likely to develop this into a series-parallel hybrid for future models for more power.


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