True fans of the rotary engine are praying that Mazda?s March 24 U.S. patent application means that the resurrection of this free-spirited alternative to pistons is not far off. While it?s been nearly four years since the final rotary engine was built for an RX-8, hope springs eternal that Mazda?s sacred powerplant will hum again.
Since the Renesis II 16X engine program was introduced at the 2007 Tokyo Motor Show, Mazda has insisted that its engineering team had been working feverishly to bring a new rotary up to modern power, fuel-consumption, exhaust-emissions, and reliability standards. Last year Mazda stole the Tokyo show with its RX-Vision two-seat coupe concept, which presented a stunning wrapper but no engine updates beyond a fresh rotary-engine name: SkyActiv-R. What we know about the SkyActiv-R is that it features a 23-percent-larger displacement than the 232-hp 13B engine which powered the RX-8.
The larger size and internal geometry changes are aimed at solving a key rotary issue?the impression that no one?s home at low rpm. To save weight, the SkyActiv-R uses aluminum end plates where the 13B used iron pieces instead. Injecting fuel closer to the combustion chamber improves fuel efficiency.

The Mazda RX-Vision concept won the Tokyo auto show last fall.
Even though turbocharging is contrary to core SkyActiv tenets, this new rotary will definitely be turbocharged to produce the 400-plus horsepower it will need to compete against Corvettes, Jaguars, and Porsches....