We wept nerdy tears when Mazda announced the end of the RX-8. It was more than the end of a fun, quirky, rear-driving sports car with suicide doors. We loved that since we first saw Wolverine steel Cyclops’ example in X-Men 2. But we cried more for the death of the Wankel. The RX-8 was the last production car to use a rotary engine.
But this is not a downer piece. Mazda announced this week at the Moscow Motor Show that the rotary will be back, and in rather uncharacteristic terms.
Let’s say you’re unfamiliar with the Wankel rotary engine. You wouldn’t be alone. Even a lot of car people would be perplexed to see one. Developed by German inventor Felix Wankel before World War II, the rotary engine was designed to be a simple, highly efficient alternative to the traditional piston-driven setup we find in nearly every car on the road.
Its workings are best described visually, rather than verbally, but in the most basic terms, a rotary uses a rounded triangular gear that spins inside a rounded rectangle, with compression, combustion, and exhaust each constantly occurring on one side of the triangle. A piston within a traditional engine has to “stop” twice within each cycle, once at the top, and once at the bottom. The rotary keeps going.
The triangular rotary gear serves double duty as its own valves, so there are fewer moving parts within a rotary engine. It’s a much simpler design. It’s also much smaller and lighter than a conventional engine of similar output, and usually wears a much higher redline, peaking at exciting places on the tachometer.
Several manufacturers have been interested in rotary engines throughout the years. GM originally planned one for their ill-remembered Monza, but dropped it before production. Many small aircraft take advantage of the Wankel’s small size and good power to weight ratio.
But no one has carried the rotary flag higher than Mazda. Throughout the ‘70s and ‘80s, Mazda built several rotary-powered cars and trucks, trumpeting the Wankel’s “quiet power,” since “A piston engine goes boing boing boing, but a Mazda goes hmmmmmm.” The most notable Mazda R’s however, were sold to people who didn’t care so much about the noise.
The RX-7 is a legend in the sport import segment. Its flat little rotary rode snugly up next to the firewall, which meant great handling and weight distribution. Spanning three generations, it grew from a classy grand-tourer to a beastly drift and track monster. Its scion, the RX-8, never earned the hardcore cred of its fathers, but remains a neat venture, and is still used widely in Grand-Am racing (so there). We saw a beautiful example of a third-generation FD RX-7 at Woodward.
It was Faster and more Furious than any example I’ve ever seen in the metal, packing a freakishly huge turbocharger and a couple of nitrous bottles tanks. But here we come to one of the rotary’s chief shortcomings: forced induction. As any Mazda tuner will tell you, apex seals, comparable to piston rings on a conventional engine, don’t do well with higher than stock compression. Sitting at the tips of the triangular rotor, they have to come close enough to the cylinder walls to prevent wasted compression, but not close enough to strike them. Put enough pressure behind these precision-cut spearheads, and they’ll break. Tuners often employ aftermarket seals.
Rotaries also suffer from smog shackles. With such a quick, streamlined combustion process, they tend to spit unburned hydrocarbons, and apparently baby seals and polar bears don’t like those. Nor has fuel efficiency ever been quite as high as Wankel dreamed.
Which is why Mazda’s newest rotary application, a hybrid, seems like such a strange outfit. Speaking in Moscow, Mazda’s Takashi Yamanouchi said, “We are still learning. The rotary has very good dynamic performance, but if you accelerate and brake a lot there are efficiency disadvantages. The range extender overcomes that. We can keep it spinning at its most efficient 2000rpm while also taking advantage of its size.”
An interesting idea, keeping a rotary spinning to prevent it having to spool back up again. Rumor has it the new rotary will also use direct injection and (get ready) laser ignition. Neither of these are particularly new ideas, and direct injection has been used successfully on several platforms, including Ford’s Ecoboost, but between this and the awesome frickin’ lasers detonating the fuel, smog problems could be averted.
Eventually, though, we have to stop and wonder: Why? Most of Mazda’s cars don’t use rotaries. And Mazda have never been massively successful like the larger companies, even when Ford owned a huge bite of their efforts. Nor is this new rotary Mazda’s only experimental superhero engine. Their Skyactiv series has been impressive to say the least. One Skyactiv 3-cylinder (unfortunately still in development) can manage 73 mpg. Without electrics. So why this renewed venture into a half-successful idea?
The answer lies in the character of the company. Mazda are, and have always been, risk takers. What other Japanese company would build a low-cost British sports car, especially with one sports car already in their lineup? Who else would drop a stick shift in a minivan and be proud of it? Who would dare to put a huge, creepy Joker smile on every car they build? Mazda doesn’t need to build another rotary, they simply want to. And Mazda does what Mazda wants.