2004 Mazda Rx8 Gt W/ Sport Package 6-speed Manual 46,xxx Miles Must See !! on 2040-cars

Auto blog

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.

Mazda3 Skyactiv-Hybrid and CNG Concept shown in Japan

Mazda has received a tremendous amount of public and industry praise in the last few years, following up the successful introduction of its Skyactiv technology (powertrain and otherwise), with strong products like CX-5, Mazda6 and most recently, the Mazda3. At the Tokyo Motor Show, Mazda has taken yet another step forward with Skyactiv and the 3, showing the compact (called "Axela" in Japan) with an all-new compressed natural gas engine in the Skyactiv-CNG Concept.
The end result of the Skyactiv-Hybrid is fuel consumption estimated at something like 74 miles per gallon.
Mazda thinks that CNG-powered vehicles are due for an uptick in demand, and the company believes this new powertrain will add valuable breadth to the Mazda3 range. The CNG Concept is actually a duel-fuel vehicle, capable of running on either natural gas or gasoline. In fact, we're told that the high compression ratio (14:1) inherent in Skyactiv-technology gasoline engines makes conversion to CNG particularly simple.

Mazda returning to top-tier racing with diesel-powered prototype in USCC

Mazda has unveiled its latest challenger in the top flight of endurance racing, a diesel-powered prototype that will campaign the inaugural, 2014 Tudor United SportsCar Championship. The new Skyactiv-D-powered car will make its race debut at January's Rolex 24 at Daytona.
"This is the most significant step Mazda has taken towards returning to the global racing stage since our overall victory at Le Mans in 1991," said the director of Mazda Motorsports, John Doonan. That historic racecar, the rotary-powered 787B, has grown to become one of Mazda's many, well-known racers.
More recently, the Japanese brand has been making waves in the Grand-Am series, campaigning RX-8s and, most recently, running diesel-powered Mazda6 sedans in the GX-class. Mazda will campaign two factory-backed prototypes at Daytona. Driver lineups will be announced closer to race day.