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Mazda Skyactiv-X Review | The revolution begins with a squeeze-bang

The matte black Skyactiv-X prototype looks like a rough Mazda3, perhaps reconstructed after a bad wreck by an over-enthusiastic owner of a spot welder and lots of gaffers' tape. Ribbed ducts poke out of the dash sending two breaths of conditioned air to no one in particular. Even its revolutionary engine, the thing we're here to experience, is entombed in a massive, nondescript cover to mask its unseemly noises. It's a wild, strange way to meet a very unconventional vehicle that promises diesel-like fuel economy, a wide torque band, and an exotic method for burning less gas than ever before. It takes a few hours for Mazda's engineers to explain the fundamental principles of operation. For more detail, read our Skyactiv-X Spark Controlled Compression Ignition explainer, but here's a very brief overview. Skyactiv-X marries some traditional gasoline engine characteristics with a novel form of compression ignition called SPCCI. The key for Skyactiv-X is to use very high compression in the cylinder and an extremely lean fuel-air mixture. Squeezed right to the cusp of getting hot enough to blow up all on its own (which is very hard to predict), a squirt of extra gas and a spark interject to cross that compression-ignition threshold in a controlled and predictable manner. See the animation below: That takes a few essential components to get just right. One is a massive amount of computer processing power and some pressure sensors in the individual cylinders, because the ambient conditions change how and when these things happen. Skyactiv-X uses a clutched supercharger to pump in additional air when needed to nail the mixture precisely, and high-pressure injectors to get the low ratios of fuel to disperse properly in the chamber. And since it operates like a conventional gasoline engine sometimes, it uses valve timing to lower the very high compression ratio so it doesn't reach combustion ignition in that mode. In practice, the Skyactiv-X runs in compression ignition mode most of the time. In practical terms, that means it drives like a torquey gasoline Skyactiv engine. The torque curve is broad and flat — diesel-like in that respect. That also means it can get away with using a six-speed transmission and a lower final drive for better response. There's enough grunt and economy together that Mazda can let the engine spin faster — at 60 mph, it's running at roughly 1,000 more RPM than a similar gas engine, with greater efficiency.

2017 Mazda CX-9 Prototype First Drive

If you read our coverage from last week's Los Angeles Auto Show, you'll note that we were extremely fond of the new Mazda CX-9. We like the look of the thing, inside and out, and it promises to be the best-driving entry in the three-row crossover class. We agree wholeheartedly with that claim. You see, we already drove it. Full disclosure: Our test of the camouflaged CX-9 prototype you see here was short, and while we were able to get a good handle on the CX-9's basic driving dynamics, it'll take more than a 30-mile session around the outskirts of LA to uncover the finer details. What's more, these vehicles are not production ready. In fact, according to our handlers at Mazda, the CUV we tested was actually at the stage before pre-production – so basically, a pre-pre-production car. That said, all the details about the engine, transmission, suspension, and steering are "largely final." As you can see in the gallery, the cars we tested were heavily camouflaged both inside and out. As for styling, we love it – see the undisguised pictures from the LA show for more views. And as for inside, we can say leather seats of our Grand Touring model were comfortable and supportive, and the smallish steering wheel felt natural in the hand. Even in pre-pre-production state, the CX-9 was impressively quiet. An extra 53 pounds of under-floor sound deadening, thicker windows, and active noise cancellation all contribute to what Mazda claims will be "among the quietest vehicles in its class." It's worth noting that the good sounds, like the throaty, whooshy noises of the turbocharged engine, found their way into the cabin just fine. The 2.5-liter, turbocharged four-cylinder engine – Mazda's first force-induced Skyactiv engine – is an excellent piece. The 2.5-liter, turbocharged four-cylinder engine – Mazda's first force-induced Skyactiv engine – is an excellent piece. It uses a variable geometry turbocharger, which the company calls a Dynamic Pressure Turbo. Here's how Mazda explains it: Imagine a normal garden hose. Put your thumb over the nozzle, and the force of the water increases dramatically. That's the DPT at low rpms. It features three small exhaust ports to direct exhaust gases into the turbo, making for 17.4 quick-spooling PSI at low rpms. As the revs climb, a flow control valve opens up, redirecting the gases to a trio of larger ports – removing your thumb from the hose, if you will – and keeping the boost up.

Mazda3 officially unveiled

Mazda has officially pulled the sheets off of its 2014 Mazda3. The all-new compact boasts a wheelbase that's a full 2.4 inches longer than the outgoing model, yet the hatchback is a nearly two inches shorter from stem to stern. The machine is also lower and wider than before, which should give occupants plenty of space indoors. The driver gets treated to a new human-machine interface that features a new Active Driving Display for information like vehicle speed and navigation instructions conveniently in the line of sight. Likewise, the vehicle's infotainment system has received a complete rebuild.
Outside, the new Mazda3 makes full use of the company's KODO design language, and to our eyes, the result is one of the most attractive entries in the segment. Jump under the hood, and buyers can expect to find a Skyactiv-G 2.0-liter gasoline engine with 155 horsepower and 150 pound-feet of torque, though no fuel economy estimates are available. For those looking for a bit more thrust, Mazda also offers a 2.5-liter Skyactiv-G gasoline mill with 184 hp and 185 lb-ft of torque. So far there's no word on the diesel engine available to our friends in Europe.
Both engines can be mated to either a six-speed manual or a six-speed automatic and feature the automaker's i-ELOOP brake energy regeneration systems. The recaptured energy is stored in a capacitor and used to power the vehicle's various electrical systems.