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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.

Nissan gives a better look at its Vision Gran Turismo concept

Just the other day, Nissan released an image showing all of its cars you can drive in Gran Turismo, with one little mystery hiding in the bottom right corner: a draped shape with the date June 10, 2014 - suggesting that it would reveal its Vision Gran Turismo on that date. Well, if you look at that calendar you'll realize that June 10 came and went yesterday, and Nissan didn't reveal the car.
As it turns out, what the folks at Nissan meant when they indicated June 10 was that they'd release the next teaser on that date, and that's what we have here. The teaser hints at one menacing-looking futuristic chunk of virtual performance meta, but "the next chapter" won't be revealed until next week on Monday, June 16. At that point we hope Nissan will actually reveal the full thing and not another teaser, but one way or another the finished product is expected to be present in the flesh (or sheet metal) for the Goodwood Festival of Speed at the end of the month.

Nissan bringing GT-R LM Nismo to Le Mans in 2015 [w/videos]

The Nissan Zeod RC hybrid racecar is certainly cool with its pointy looks, we're excited to see it run, but it isn't built to win races so much as push boundaries. But we might not have too to wait long for one of the Japanese brand's vehicles to claim an overall victory at the 24 Hours of Le Mans, as well. The company is announcing the GT-R LM Nismo racecar with a two-car, full factory effort in the top LMP1 class of the 2015 FIA World Endurance Championship, including Le Mans.
Details about the new racer are almost nonexistent at the moment. The only glimpses that we have are its silhouette under a sheet (above) and the briefest peek at its quad circular taillights in one of the teaser videos. However, the team is making some big promises about the car. "We want to win in a very different way to that of our rivals. We won't be turning up in a vehicle, which is a basically another hybrid that looks like another Porsche, Audi or Toyota - they all look the same to me," said Nissan's Chief Planning Officer and Executive Vice President Andy Palmer in the official announcement. Mechanically, Nissan is revealing even less about the GT-R LM Nismo for now. We are just going to have to wait and find out.
The brand will be aiming for a win in the 24-hour race, but it won't come easy. Nissan will absolutely face stiff competition from the combined forces of Audi, Porsche and Toyota in the top LMP1 class. Scroll down to watch two teaser videos for the newest member of the GT-R family and read the full announcement.