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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.

Nismo toying with crossovers and pickups

Nissan is apparently committed to turning its racing and tuning division into a bigger player, with new Nismo models coming out all the time. But while the Nismo division has until now focused primarily on hatchbacks and sports cars, the next project could be a truck. According to Aussie website CarAdvice in speaking to Nissan marketing chief Darren Cox and Nismo boss Shoichi Miyatani, the prospect of a Nismo-tuned SUV or pickup are definitely on the table. That could include a performance-oriented take on the Navara pickup, but also the Qashqai crossover – a prospect first mooted a year ago. And if the Qashqai and Navara are under consideration, there's no telling what Nismo might do with the likes of the Frontier, Rogue, Murano or even the Pathfinder. None of that is concrete at the moment, of course, but the market for performance crossovers seems only to be growing – and growing more accessible, too. The Germans keep making smaller crossovers and performance variants thereof, and even Fiat is said to be working on an Abarth version of the 500X. The Juke Nismo itself bridges the gap between hot hatches and performance crossovers, but apart from the 370Z Nismo and GT-R Nismo, most of the division's projects seem to be focusing on hatchbacks like the Pulsar and Versa Note.

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.