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Weekly Recap: New bosses try to jump-start Cadillac and Lincoln

Both of America's domestic luxury brands seem to be stuck in neutral.
It's ironic that Cadillac and Lincoln got new bosses within days of each other this month. It's also a commentary on the fact both of America's domestic luxury brands seem to be stuck in neutral.

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.

Autoblog sell-it-yourself highlight: 2013 Infiniti QX56

As Lincoln announces an all-new Navigator at this year's New York auto show, and General Motors' Arlington (Texas) plant runs 24/7 cranking out Tahoes, Yukons, and Escalades, Infiniti's big QX56/80 continues to gain fans in a great many upmarket zip codes. And its appeal – for those with an appreciation for Big Foot footprints – is obvious. Built atop Nissan's Patrol platform, the QX56 offers high levels of refinement with cubic yards of utility. Introduced by Nissan's Infiniti division in 2011, you would assume any inaugural bugs had been worked out by 2013, the QX's third model year. Power was supplied, in the press vernacular, by Nissan's proven 5.6-liter V8 producing 400 horsepower and 413 pound-feet of torque. A seven-speed automatic transmission was standard on all models, and while the additional speeds might suggest some semblance of efficiency, no one should confuse this big QX with a Toyota Prius. Our 'for sale' example, with 84,000 miles, represents above-average mileage for a 4-year old vehicle. But if those are largely highway miles in and around Madison, Mississippi, and service records are available, you shouldn't be too concerned. This is, with proper maintenance, a 200,000-mile platform, leaving you about 116,000 miles for your $37,000. And the 'ask' seems about $5,000 too dear; perhaps the seller will throw in a gas card. Related Video: Infiniti Car Buying Used Car Buying Ownership SUV Luxury