2003 Mazda Miata Se Convertible 2-door 1.8l on 2040-cars

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Mazda3 with Skyactiv-X engine technology caught testing in the wild

Sometimes, automakers are fine with their mules coming under the watchful lenses of spy shooters. Proof of this can be seen plastered across the bodysides of the Mazda3 mule you see above. Clearly, Mazda wants the world to know that engineers are working hard on the company's so-called Skyactiv-X engine technology so badly that it's created a custom matte black vinyl wrap for its test mules. Clever. Expect to see this sweet new engine tech in the 2019 Mazda3. This SCCI, or Spark Controlled Compression Ignition system holds tremendous potential to boost the efficiency of gasoline-powered engines by 20-30 percent, thereby matching the fuel economy of a comparatively sized diesel engine. As an added bonus, torque figures are expected to jump a similar amount. Besides the placard-sized stickers, there isn't much to see here. The car is clearly a Mazda3 hatchback, though the fenders are punched out a bit and the fuel door is modified from stock. We'd wager that future prototypes will wear a lot more camouflage to cover up next-gen bodywork. In other words, stay tuned. Related Video: Featured Gallery Mazda3 Skyactiv-X: Spy Shots View 9 Photos Green Spy Photos Mazda Fuel Efficiency Technology Emerging Technologies Hatchback skyactiv mazda mazda3 skyactiv-x

How Mazda got Skyactiv-X to work is incredible

"Take everything you know about engines and turn it around," Mazda North America Vehicle Development Engineer Dave Coleman says, patiently and with a look of benevolent pity, as he's quizzed about the particulars of the company's new engine. The Skyactiv-X engine is enigmatic — and deceptively simple in operation. And the bottom line for American consumers is that they'll be able to buy a car (or crossover; we don't know yet what vehicle will first get it) by late 2019 that provides diesel-like fuel economy but runs on regular old gasoline. In between diesel and spark ignition, but it's neither To truly understand it, you have to dive into the contradictions. Take that regular old gasoline: Contrary to common sense, the lower the octane, the better it works. In the lab, the Skyactiv-X engine loves 80 octane. The lowest Americans get is 87, so the engine is tuned for that octane. Go higher and you lose some low-end torque. Coleman was right. It's hard to wrap your head around an engine that thrives just at the point when most gas engines would aggressively self-destruct. It uses a supercharger to pump additional air — but not additional fuel. It uses spark plugs to start a combustion cycle that normally doesn't need a spark. And, quixotically, it's not displacing Mazda's own American-market diesel engine, currently languishing in a seemingly endless hell of regulatory approval. More bizarre: Mazda is a tiny automaker facing real existential headwinds, and gasoline compression ignition is a massive challenge. GM and Hyundai announced compression ignition, or HCCI, projects (full name, homogeneous charge compression ignition) to great fanfare, but they never amounted to a production hill of beans, crippled by reliability issues or horrible vibrations. Worse, they only worked at an unusably narrow range — low RPMs and low loads. HCCI research improved direct-injection gas and diesel engine technologies for these companies, but HCCI itself remains untamed. The benefits of lean combustion Why even try to tame HCCI? The answer is much better fuel economy and lower emissions. Less burned carbon-based fuel, less carbon dioxide released. That's simple. But there are some thermodynamic reasons for the lean combustion you can achieve with compression ignition that are worth explaining. The ideal amount of fuel for a conventional engine to burn is about a 14:1 air-to-fuel ratio. That lets every molecule burn nicely, in theory.

This is what a 1,200-hp twin-turbo 4-rotor looks like in a Miata

We've seen the diminutive Mazda MX-5 Miata swallow plenty of big engines, but New Zealand drifting ace "Mad Mike" Whiddett is roaring into where-no-man-has-gone-before territory. Wanting to replace his 515-horsepower "MADBUL" RX-7 and its twin-turbocharged, three-rotor 20B engine, his new ride is an NC-series Miata with four rotors and twin Garrett turbochargers courtesy of Pulse Performance Race Engineering. It is called "RADBUL," and expected power at standard boost is 1,200 hp, but the builders at Pulse Performance think it will get up to 1,500 hp at full boost. And yes, that exhaust exits through the hood. Four-rotor engines are actually popular - builds are detailed on forums like this one from 2007 and this one from 2008, this UK company or this Canadian company will sell you one complete - but they're usually being prepped for an RX-7. Mad Mike's choice of a Miata for this enterprise makes this about as extreme as you can get, short of throwing it into a Mazda R360. You can watch Mad Mike tell the story of the build in the video, and check out the first and second installments about the build on the Red Bull site.