2007 Nissan Sentra 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.

NHTSA urges owners of recalled Takata airbag vehicles to take immediate action

The National Highway Traffic Safety Administration and the Department of Transportation are taking the unusual step of issuing a followup press release urging owners of certain recalled vehicles "to act immediately" to fix their cars and trucks. The problem in question concerns the repair campaigns for rupturing Takata airbag inflators issued in June and covers a long list of models from Toyota, Lexus, Honda, Acura, Mazda, BMW, Nissan, Infiniti, Buick, Cadillac, Chevrolet, GMC, Oldsmobile and Pontiac.
While NHSTA doesn't specifically say why the recall is vital in the new release, Toyota's own explanation in its newly announced renotification campaign earlier today sheds some new light on the topic. According to the Japanese automaker, in testing, Takata found a possible link between the rupturing airbag inflators and high humidity. NHTSA is advocating that all owners pursue repairs immediately if they haven't already done so already. This is especially crucial for those drivers especially in Florida, Puerto Rico, Guam, Saipan, American Samoa, Virgin Islands and Hawaii because of the humid conditions there.
We don't need to tell you how dangerous an inadvertent airbag deployment could be - even in a stationary vehicle - but adding to the Takata issue is fears that the deployment could lead to shrapnel being sprayed into the cabin.

2014 Nissan GT-R Track Edition loses rear seats, gains performance

Nissan is adding yet another tier to the GT-R hierarchy for 2014 with the GT-R Track Edition. Debuting at the 2013 Chicago Auto Show, the bruiser ditches its back seat in the quest for a lower curb weight, and a set of more seriously bolstered front buckets keep occupants planted once the going gets twisty. The Nürburgring-developed Track Edition offers an integrated carbon fiber front splitter with brake cooling ducts as well as an even harder-core suspension. Engineers swapped the stock bits for special Bilstein DampTronic shocks and paired them with more aggressive springs.
The engine still delivers 545 horsepower and 463 pound-feet of torque and still relies on the split-second quickness of the standard GT-R's six-speed dual-clutch transmission. Expect to see just 150 examples of the 2014 Nissan GT-R Track Edition land on American shores starting this May. In the interim, check out the full press release below for more information.