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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.

MotorWeek proves '90s were awesome with Supra, Stealth, RX-7, Corvette, 968, 300ZX comparo

Oh, the heady days of 1993, back when the Clinton Presidency was just getting underway, and it seemed like every hot new rock band was coming out of Seattle. Sports cars in the US had finally shaken off the shackles that slowed them during the '70s and '80s, and you could buy any number of legitimately quick vehicles again. MotorWeek recently went digging into its archives to find this six-model test from 1993 showing off some of the best semi-affordable performance coupes that money could buy at the time, and it's priceless.
Featuring the 1994 model year Toyota Supra in twin-turbo guise and MY 1993 versions of the Porsche 968, Nissan 300ZX TT, Mazda RX-7, Dodge Stealth R/T Turbo and Chevrolet Corvette LT-1, MotorWeek definitely covered all of the bases. One thing that might surprise younger readers is these cars' performance. The video only provides 0-60 acceleration times, but several of these vehicles would still be considered pretty potent today - over 20 years since going on sale. The Supra is especially impressive, hitting 60 miles per hour in just 5 seconds. Even today, that's nothing to sneeze at.
Given their performance potential and still-attractive looks, it's amazing that some of these coupes are old enough to drink now. The progress of interior design and safety equipment in the intervening years is pretty shocking, though. In most of these models, having two airbags is touted as a big deal. Scroll down to watch a Throwback Thursday blast from the past about some of the '90s best sports cars.

Nissan Juke-R pitted against Bugatti Veyron in brilliantly odd drag race

The Nissan Juke-R must've been a tough car to build a business case for, yet the madcap little crossover with the heart of a GT-R is now a production reality. Admittedly, we should probably assign some quotes around "production," since the vehicle is being built on a one-by-one on-demand basis at extraordinary cost - at an estimated price of well over $600,000, it has little in common with the already bonkers everyday Juke. We're just happy it exists at all.
With 545 horsepower, we also didn't figure it needed more power. But that apparently hasn't stopped the tuning community, which probably only had to adapt performance adders designed for the GT-R to the mechanically similar CUV. Thus, we end up with this mile-long drag race, which pits a Bugatti Veyron against a Juke-R prepared by an outfit called Shpilli Villi Engineering with a claimed 700 horsepower. That's still well down on horsepower versus the legendary quad-turbo supercar, but the much smaller Nissan also figures to be a lot lighter while boasting similar all-wheel-drive traction. We don't have much more information to go on other than this video, and it doesn't appear that both drivers necessarily got their best runs in, but it certainly makes for jaw-dropping watching. Check it out by scrolling below.