2014 Nissan Quest S on 2040-cars

Auto blog

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 Quest under investigation for inaccurate fuel gauges

After receiving 12 complaints in the last 14 months, the National Highway Traffic Safety Administration has begun a preliminary investigation into a fuel gauge issue with the 2007 Nissan Quest. Drivers have reported that the fuel level gauge will show there's gas in the tank when there actually isn't - in two cases, the digital distance-to-empty gauge indicated more than 70 miles of remaining range - and it will stall out.
This is the second time the 2007-model-year Quest has been involved in the same fuel gauge issue. In 2010 Nissan recalled seven models, including the Quest, from the 2005-2008 model years because of faulty fuel readings. The 12 vehicles in this latest complaint could have slipped through the cracks then, but we'll find out more when NHTSA updates its progress with the investigation into the estimated 37,656 units.

Autoblog's guilty pleasure cars

Guilty pleasures are part of life – don't even try to pretend like you don't have one (or two, or six). In the non-automotive space, this could come down to that secret playlist in your iPhone of songs you'll only listen to when you're alone; or think of that one TV show you really do love, but won't admit to your friends. I've got plenty, and so do you. Going back to cars, here's a particularly juicy one for me: several years ago, I had a mad crush on the very last iteration of the Cadillac DTS. Oh yes, the front-wheel-drive, Northstar V8-powered sofa-on-wheels that was the last remaining shred of the elderly-swooning days of Cadillac's past. Every time I had the chance to drive one, I was secretly giddy. Don't hate me, okay? These days, the DTS is gone, but I've still got a mess of other cars that hold a special place in my heart. And in the spirit of camaraderie, I've asked my other Autoblog editors to tell me some of their guilty pleasure cars, as well – Seyth Miersma, as you can see above, has a few choice emotions to share about the Mitsubishi Lancer Evolution. Read on to find out what cars make us secretly happy. Mercedes-Benz SL65 AMG This decadent convertible is the epitome of the guilty pleasure. It's big, powerful, fairly heavy and it's richly appointed inside and out. It's a chocolate eclair with the three-pointed star on the hood. Given my druthers, I'd take the SL65 AMG, which delivers 621 horsepower and 738 pound-feet of torque. That output is borderline absurd for this laid-back convertible. I don't care. You don't need dessert. Sometimes you just crave it. The SL line is about the feel you get on the road. The roof is open. The air, sun and engine sounds all embrace you. It's the same dynamic you could have experienced in a Mercedes a century ago, yet the SL gives you the most modern of luxuries. An Airscarf feature that warms my neck and shoulders through a vent embedded in the seat? Yes, please. Sure, it's an old-guy car. Mr. Burns and Lord Grantham are probably too young and hip for an SL65. I don't care. This is my guilty pleasure. Release the hounds. – Greg Migliore Senior Editor Ford Flex I drove my first Flex in 2009 when my mother let me borrow hers for the summer while I was away at college. The incredibly spacious interior made moving twice that summer a breeze, and the 200-mile trips up north were quite comfortable.