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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.

Jay Leno checks out Nissan IDx Nismo, spiritual successor to classic Datsun 510

Jay Leno may not be spending his night behind the Tonight Show desk anymore, but he's clearly not done rolling precious metal into his garage, intent on putting it through its paces after a thorough investigation. The latest machine to meet Jay on his home turf is the Nissan IDx Nismo Concept that we first saw at the Tokyo Motor Show late last year.
Leno already has love for the classic Datsun 510, which plays a cameo in the video that you'll see below, and he refers to the IDx as the spiritual successor to that car's ethos - driving fun in an affordable package. Fortunately for us, while the IDx is a showcar first and foremost, it is indeed driveable, and Leno, naturally, takes his turn behind the wheel.
Scroll down to watch the complete video below.

Nissan to give Qashqai the Nismo treatment

Nismo is on a bit of a rampage lately. Once consigned to the fringes, Nissan has taken its performance sub-brand into the mainstream and let it loose on a whole mess of its products. The Juke Nismo was followed by a 370Z Nismo, and in Los Angeles, we saw the GT-R Nismo, Sentra Nismo concept and Juke Nismo RS.
So what's next from Nismo? According to the latest intel from across the pond, Nissan is working on a tuned version of its new Qashqai. Car magazine is reporting that the larger crossover will get the same 1.6-liter turbo four as the Juke Nismo, but with the RS model's 212-horsepower out and not the "base" model's 197. Expect all the other bells and whistles applied to transform a Nissan model into a Nismo one to apply as well.
If the Qashqai name doesn't ring any proverbial bells for you, that's alright, because it's only sold overseas, where it's one of Nissan's most popular models. The crossover (which looks like the new Rogue but is a substantially different model) was recently completely replaced, with engine options ranging up to 150 horsepower - so the jump to over 200 should make for quite a different beast altogether. Whether a parallel or subsequent program to give the Rogue a similar treatment is another matter, but given the pace at which Nismo seems to be running, that may only be a matter of time.