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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.

Infiniti hires Sebastian Vettel as Director of Performance

Remember when, during the Grand Prix of the Americas weekend last November, we told you that Sebastian Vettel had worked with Infiniti on the new G Coupe and that there'd be more of that kind of involvement on the way? It's been made official with the three-time Formula One World Champion being named Infiniti's Director of Performance.
Although the announcement is fresh, Vettel's time on the job isn't, Infiniti saying that Vettel went to Japan, the Nürburgring and the Circuit de Catalunya to assist in the development of the Q50 sedan.
When we spoke to Andreas Sigl, the man in charge of Infiniti's F1 collaboration with Red Bull, about the tie-up he had also said, "Like Mercedes has AMG and BMW has M - whether it's called IPL or not - we want to have something in that space." If the brand is still serious about that, Vettel's chops could help them deliver the kind of performance they'd need as upstarts to challenge the ringleaders of that particular hi-po circus.

Eau Rouge Lite: Infiniti Q50 gets 400-hp, twin-turbo V6

The Infiniti Q50 Eau Rouge is still (probably) dead. But as consolation prizes go, a new 400-horsepower, twin-turbocharged V6 isn't bad. The 3.0-liter biturbo will be offered in two different states of tune. Enthusiasts will flock towards the aforementioned 400-hp model, but the first VR series engine will also be sold in a 300-hp version, as well. Regardless of output, both engines have a very broad torque curve, ranging from 1,600 to 5,200 rpm with either 350 or 295 pound-feet. A Mercedes-sourced, 2.0-liter, turbocharged four-cylinder will serve as the Q50's new base engine, matching the CLA250's 208 hp and 258 lb-ft of torque. The hybrid powered Q50 soldiers on, as do a line of standard seven-speed automatic transmissions. The naturally aspirated 3.7-liter V6 appears to be gone. Another big enhancement for the updated Q50 is a revised version of the widely disliked Direct Adaptive Steer system. Infiniti says its engineers "optimized the control logic to improve feedback from the road" – a huge area of complaint with the current steer-by-wire system. The Q50's new engine lineup will be showrooms later this winter. Read on for the official press release from Infiniti, and stay tuned for more from the brand – including the new Q60 Coupe – at the upcoming Detroit Auto Show. Related Video: Infiniti Announces New 3.0-liter V6 Twin-Turbo Engine – the Most Advanced V6 Ever Offered by Infiniti • New VR-series engine becomes the lightest, most powerful, cleanest and most fuel-efficient V6 engine that Infiniti has ever offered• Two power outputs available: 400 or 300 horsepower• Series of technical innovations enhance drivability and performance• Compact layout features new integrated exhaust manifold• The 3.0-liter V6 twin-turbo engine family will first be available in the 2016 Infiniti Q50 sports sedan NASHVILLE (Dec. 15, 2015) – Infiniti's new compact, lightweight 3.0-liter V6 twin-turbo engine is the most advanced V6 engine that the brand has ever offered, striking an ideal balance between drivability, efficiency, and performance. The 3.0-liter V6 twin-turbo is an all-new engine from the new and exclusive VR- series powertrain family, born out of the brand's longstanding heritage of V6 powertrain production. The new engine has been engineered to empower the driver and offer increased power and torque and higher levels of efficiency than any comparable predecessors from the company.