2011 2.5 Sl Used 2.5l I4 16v Fwd Sedan on 2040-cars

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Infiniti's new VC-T changes the rules of small turbocharged engines

The upcoming Infiniti QX50 crossover does not get our pulse racing, no matter how shapely the QX Sport Inspiration concept that previews it may be. No midsize SUV does, to be fair. But it has something special under the hood – the world's first production variable-compression-ratio engine. That means the QX50's 2.0-liter turbo four, which makes 268 horsepower and 288 pound-feet of torque, will have up to 27 percent better fuel economy. Here's how it works. The trend of moving to smaller, turbocharged engines carries with it one big falsehood. Under low load when the turbo isn't needed, these engines are less efficient than an equivalent engine without a turbo because of the low compression ratio the turbo requires. That is, if you never need the extra power, you're wasting fuel. Turbocharged (and supercharged) engines use a lower compression ratio to prevent detonation. When you force extra air in a cylinder and mix it with fuel, it's more likely to prematurely go boom. Lowering the compression ratio prevents this problem, but it's less efficient. Infiniti's VC-T promises the best of both worlds, with a compression ratio that ranges from 8.0:1 for high-power turbo needs to a 14.0:1 ratio for fuel-sipping efficiency. At its heart the VC-T engine is a simple idea, but it's complicated to explain. Consider yourself warned. The photo below from Infiniti serves as a good visual overview. For the truly nerdy, this patent application covers the mechanical concept. Instead of having the pistons connected to the crankshaft, Infiniti's engine has a pivot arm with a connection on each end. One end connects to the piston, the other connects to a second lower shaft, which is controlled by an actuator arm. At any given time the engine's pistons move up and down according to the lobes on the crankshaft. But the actuator arm can change the angle of the pivot arm up and down. That is, the pistons still move in the same motion with the same stroke, but phase the entire stroke up or down. Move the pivot up and there's less room at the top, which means a higher compression ratio. Move the pivot down and the compression ratio goes down, too. As an added bonus, the lower shaft eliminates the need for counter-rotating balance shafts. Infiniti says this system works constantly and can vary the compression ratio to any number between 8:1 and 14:1. It also uses electronic variable valve timing on the intake valves to switch into Atkinson-cycle combustion for greater efficiency.

Nissan 370Z Nismo freshening coming tomorrow

Nissan is set to bring a special to the Fairlady faithful at the annual ZDAYZ fest. Based on the sole teaser and the event it's being unveiled at, it's pretty clear that Nissan is going to be issuing some kind of update to the Nismo version of its 370Z.
What that update is, though, is unclear. We can see a few small visual tweaks, like the horizontal LED running lights and their associated vertical vent. The grille looks reformed as well. Beyond that, though, it looks like we're stuck waiting for the full details until tomorrow afternoon. Until then, take a look below for the world's shortest press release.

Datsun expands low-cost revival with new Mi-Do in Moscow [w/video]

Those who were disappointed when Datsun changed its name to Nissan over three decades ago may have been pleased to see the marque revived last year, even as a budget brand. Nissan's counterpart to its ally Renault's Dacia budget brand, Datsun has been steadily expanding its lineup of low-cost transportation for developing markets with the debut of the Go hatchback in India, the Go+ minivan in Indonesia and the On-Do sedan in Russia. And now it has returned to Moscow to reveal its fourth model, the Mi-Do.
Based closely on the On-Do sedan (which itself is based on the Lada Granta) the Mi-Do takes on a five-door hatchback bodystyle but with no more frills. It uses the same front-drive chassis with the same wheelbase as the sedan, but its chopped tail makes it a good foot and a half shorter overall. Into that compact shape, Datsun has fitted dual airbags, ABS and... well, that's about it. It's got a 1.6-liter, eight-valve inline-four kicking out a grand total of 87 horsepower to either a five-speed manual or a four-speed automatic. Bare bones, this is.
While delivery of the first On-Do sedans commences next month (with the first example going to an IT specialist in Omsk), the Mi-Do is set to begin delivery early next year. Scope out the video and press release below from the Mi-Do's reveal at the Moscow Motor Show.