1987 Mazda Rx7 Convertable, Rotary Engine, 5 Speed Trans. on 2040-cars

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Mazda files patents for a sequential twin-turbo setup

Mazda has a history of interesting engine technologies, from yesterday's rotary engine to tomorrow's compression ignition engine, and new patents show it still may have some internal combustion tricks up its sleeve. The one on display in these patents isn't especially new in concept, though. A sequential twin-turbocharger setup is something Mazda itself used on the third-generation RX-7. But it's something we haven't seen much of lately. It looks like it could have some possible advantages over older sequential systems, and it has some potential advantages for enthusiasts. First a quick and dirty primer for what makes a sequential twin-turbo system distinct from other twin-turbo systems. In many twin-turbo engines, there are simply two turbos that work together as one bigger turbo. They're the same size, and they spool up at the same time. With a sequential setup, at low rpm, a smaller turbocharger is spooled up first at low-rpm for quicker throttle response, and as the rpm and exhaust pressure increases, a valve opens up that allows a larger turbocharger to also spool up and provide high-rpm boost. That's basically how the Mazda design shown above functions. A big flap blocks off the larger turbocharger exhaust inlet, channeling all the exhaust to the smaller turbo. When more exhaust is available at high rpm, it looks like that flap opens up to spool up the big turbo, too. What's interesting here is that the way the turbochargers are packaged takes up less space than past systems. It looks like both turbos are contained in one unit that shares the same exhaust outlet, meaning the exhaust manifold could be kept simple and compact. In fact, the piping for compressed intake air could also be shared, reducing the amount of piping, which would further decrease the amount of materials and possible failure points. There are a number advantages of making this system smaller. The potential applications of the system are much greater, since it could fit in smaller cars with smaller engine bays. Making the system smaller also means that there won't be as much weight, which is important from both fuel economy and performance standpoints. Finally, the smaller setup likely uses fewer materials, which could make the system cheaper and thus easier to offer on a wider range of vehicles, or at least more profitable for Mazda.

Junkyard Gem: 1981 Mazda RX-7

The first-generation Mazda RX-7 was sold for the 1978 through 1985 model years, and for decades you'd see and hear these nimble little sports cars buzzing around American streets. Then, well, the apex seals went out, or owners tired of a 2,400-pound car that drank fuel like an Eldorado, or the floor pans were eaten by the Rust Monster... and then nearly all of them were gone. Enough of them remain, however, for a steady trickle to show up with depressing regularity in self-service wrecking yards. Here's a pretty solid '81 that I found in a Denver yard last month. The 12A Wankel engine in this car made 100 hp and 105 lb-ft of torque, which was very good for 1981 (considering that you could buy a new Camaro with a 115-horsepower V8 that year). The $9,385 RX-7 looked like an especially good value when compared to, say, the $11,299 Datsun 280ZX or the $8,997 Fiat 124 Sport Spider, being much lighter on its feet than the former and much quicker than the latter. View 12 Photos If you have ever considered getting one of these cars, move fast before all the restorable ones are gone! Auto News Mazda Automotive History mazda rx-7

Mazda3 five-door vs. Mazda CX-3

As a talking point, it won't rival North Korea, world hunger or Mideast peace, but the ongoing tug between car and crossover continues to resonate in the hallways of Autoblog HQ. And it might also generate some discussion on Mazda showrooms, where the Mazda3 five-door and Mazda's CX-3 crossover are parked within a few feet of each other. Not only do they enjoy proximity on the showroom, but they enjoy/suffer (your choice, depending on POV) pricing proximity on the window sticker. The Mazda3 five-door is the more mature model of the two, having been introduced to a world market in fall 2003. With a commonsense footprint enclosed by almost-organic, upscale sheetmetal, the Mazda3 – especially in 5-door form – punches well above its weight in the still-nascent hatchback category. With a redesign (third-generation) introduced in 2014, along with a more recent refresh, the newest sedan and hatchback merge Mazda's KODO design philosophy with a responsive platform, available 2.5-liter drivetrain and a comfortable – if not expansive – interior. What the Mazda3 5-door (photo at left) does not give you is the crossover's high hip point, despite having ground clearance almost identical to the CX-3 subcompact crossover. And while the stated passenger volume of the Mazda3 and CX-3 is almost identical, those cubes are arranged differently; the Mazda3 offers an interior package more linear, while the CX-3 is more upright. Mazda's subcompact CX-3 (photo at top) is a more recent entry, having been developed from the Mazda2 architecture and hitting the street two years ago. It sits below Mazda's CX-9 and CX-5 in the Mazda pecking order. And it is tiny, on a wheelbase of just 101 inches and offering an overall length of just 168 inches. It is seven inches shorter than the Mazda3, with a wheelbase five inches shorter. The net effect is a more compressed environment for passengers, along with the very real challenge of fitting something inside – such as a bicycle – even when that something has its front wheel removed. In the city, I like the CX-3's compactness, and relatively unrestricted visibility when compared to the Mazda3's overall length and lower seating. But when both are equipped with their six-speed automatics, and the Mazda3 is spec'd with its available 2.5 liter DOHC four, there's almost no comparison in their performance. With that spec the hatchback has Mazda's well-hyped zoom, while the CX-3 makes do with nothing but a 4-cylinder boom.