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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.

Chrysler, Nissan minivans earn 'dire' crash test results, says IIHS [w/video]

First introduced in 2012, the Insurance Institute for Highway Safety's small-overlap frontal crash test has become the bane of many auto engineers' existence. It's a particularly steep design challenge because it forces just 25 percent of a vehicle's front end to take the brunt of a 40-mile-per-hour impact. The newly released results of four family-minded minivans underscore just how difficult the crash test is: only one scored an Acceptable rating, and the other three did very poorly. The 2008-2015 Chrysler Town & Country and Dodge Grand Caravan, plus the 2011-2015 Nissan Quest, all received Poor ratings in the test, the IIHS' lowest possible score. The three of them showed significant crash intrusion into the driver's area. The dummy in the Nissan actually had to be cut out of the vehicle, with an IIHS spokesperson remarking, "the structure collapsed like a house of cards." In the Fiat Chrysler Automobile vans, the steering wheels moved out of the way, making the airbag less effective and letting the driver's head hit the dashboard. While it was not actually crashed, the agency is also giving the 2009-12 Volkswagen Routan a Poor score because it shares a structure with the FCA models. The newly released results of four minivans underscore just how difficult the small-offset crash test is. The refreshed 2015 Toyota Sienna (shown), conversely, earned an Acceptable rating and is also a Top Safety Pick+ because of its optional forward collision warning and automatic braking system. While the crash test dummy moved around during the impact more than the agency would have liked, sensors showed a low risk of injuries. The IIHS tested the Honda Odyssey last year, and it earned a Good overall score, the agency's best ranking. It's also a Top Safety Pick+ vehicle. The only member of the minivan segment left to test is the latest Kia Sedona, and the Institute is reportedly waiting a little longer for Kia to make changes to improve the model's performance. When reached for comment, Nissan spokesperson Steve Yaeger provided Autoblog with the following statement: "Nissan is committed to vehicle safety and believes that consumers should have information about crash protection so they can make educated buying decisions. Nissan is proud of the 2014 Quest's "good" rating in the IIHS front moderate overlap and side impact tests as well as a "good" head restraint rating.

2014 Nissan GT-R Track Pack squares off against Audi R8 V10 Plus

The team over at Motor Trend has pitted the new Audi R8 V10 Plus against the Nissan GT-R. While both of the bright red all-wheel-drive supercars are comparably matched in power output, the similarities end there. Audi offers a mid-engine aluminum coupe with a naturally aspirated V10 that spits out 550 horsepower. Nissan shows up with a more traditional coupe equipped with a 545-horsepower twin-turbocharged V6 at the front of the car.
The Head-to-Head video takes both cars to the Streets of Willow Springs in the California desert for some track work with professional racing driver Randy Pobst behind the wheel. After a day at the track, the pair head to the local mountains for some spirited real-world driving. One dominates on the circuit, while the other earns back its credibility in the canyons. We won't tell you which coupe comes out on top, but we think you may be surprised. Follow the link below to watch for yourself.