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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.

Road & Track names its 2013 Performance Car of the Year

Road & Track recently staged its first annual Performance Car of the Year test, pitting 13 new and updated performance cars against each other on track, then graduating the top six to a road test before picking a winner. Additionally, the magazine staff picked the best automobiles of the year in eight categories.
But first, let's cover the PCotY segment. Here's the list of cars brought to the comparison test: Audi R8 V10 Plus; BMW 435i; BMW M6 Competition Package; Chevrolet Corvette Stingray Z51; Ferrari F12 Berlinetta; Ford Fiesta ST; Jaguar F-Type V8 S; Jaguar XFR-S; Mercedes-Benz E63 AMG S-Model Wagon; Mercedes-Benz SLS AMG Black Series; Mini John Cooper Works GP; Nissan GT-R Track Edition; and Porsche Cayman S.
To find out the results of the comparison, head over to Road & Track's website or check the press release below, where you'll also find the magazine's top-rated vehicles in eight categories. Want more? Head over to the 2013 PCotY hub. But before you do that, take a stab at guessing the winner of PCotY (we'll give you one hint: it isn't a Porsche).

Least reliable cars and trucks of 2022

Related: Most reliable cars and trucks of 2022   Every year, Consumer Reports ranks new cars based on their predicted reliability. We often see Toyota, Lexus, and a few other automakers near the top. But on the other side of the coin, the list of least reliable vehicles sometimes contains surprises.   The organization surveys its members to determine the vehicles that exhibited the most problems over the prior year. Owners are asked about creaks and rattles, the durability of parts and trim, and mechanical issues. Consumer Reports assigns a weight to each problem and then uses them to create a score, with 100 being the best. Some familiar names appear on the list of least reliable vehicles (in order with the lowest predicted reliability score at the top), but there are a few eyebrow-raising models, followed by CR's score: Ford F-150 Hybrid: 4 Hyundai Kona Electric: 5 Lincoln Aviator: 8 Nissan Sentra: 9 Ford Explorer: 16 Chevrolet Bolt: 17 Chevrolet Silverado 1500/GMC Sierra 1500: 19 Jeep Gladiator: 21 Mercedes-Benz GLE: 23 Jeep Wrangler: 24 Consumer Reports noted that sedans are the most reliable vehicle category and found that trucks are far lower on the list. That said, the survey showed that trucks from American brands tended to have better reliability scores, so it’s surprising to see GMÂ’s big two and the Ford F-150 on the list. Part of their problematic ownership experience could be due to the fact that all three trucks have received recent updates, and the Ford was completely redesigned for 2022. New tech, fresh drivetrain components, and other improvements can upset the balance of reliability and make newer models look less dependable than their older counterparts. Related video: Green Chevrolet Ford GMC Hyundai Jeep Lincoln Mercedes-Benz Nissan Car Buying Truck Crossover Hatchback SUV Electric Hybrid Sedan Consumer Reports reliability