2009 Mazda 6 I Sedan 4-door 2.5l on 2040-cars

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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.

2019 Mazda3 fuel economy announced for AWD, hatchback models

Although Mazda engineers gave us fuel economy numbers for one configuration of 2019 Mazda3 at the car's Los Angeles debut, there were still a few versions left out. Now Mazda has released the data for every body style, drivetrain and transmission configuration. That includes the all-new all-wheel-drive iteration, which we will have a full review of this week. Discerning these numbers is a tad tricky since there are three powertrain combinations for each 2019 Mazda3 bodystyle, and they all get slightly different fuel economy. We've listed the different combinations in a chart below: There are a few key takeaways, the first being that the sedan is always the most efficient version of the Mazda3, likely because of better aerodynamics compared to the hatchback. Second, all-wheel drive will cost you fuel economy due to the extra weight of the axles and differential, and the added drag on the engine. Third, the most efficient versions of each body have the same fuel economy numbers as the outgoing Mazda3. The manual transmission-equipped Mazda3 has actually improved fuel economy over the old version by 2 mpg on the highway, and 1 in combined driving. Also worth noting is that only one trim level of the sedan is available with cylinder deactivation and front-wheel drive, and that's the top-level Premium trim. Opting for all-wheel drive on any trim or body style will come with an engine with cylinder deactivation. The hatchback is also the only Mazda3 available with a manual transmission, and it's only offered on the front-drive version.

Mazda recalls 109k Tribute models for rust issue

The Mazda Tribute is being hit with a similar recall as its platform-mate the Ford Escape underwent a few weeks ago. Mazda is recalling 109,000 Tributes from model years 2001 to 2004. On the trucks, the subframe can rust from road salt, potentially causing the lower control arm to detach. If this happens, a loss of steering control could occur.
Mazda is adding a reinforcement crossbrace for added strength on the affected models. The recall covers Tributes currently registered in or originally sold in 20 northern states and Washington, DC, where road salt is used.
The reinforcement braces aren't available yet to do the repair. Mazda will send a letter in May to owners of affected vehicles that will inform them of the problem, and a second letter telling them when the parts will be ready. Scroll down to read the full recall press release.