2011 Nissan 370z on 2040-cars

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Autoblog Podcast #318

Toyota back on top, Barrett Jackson, Crowdsourcing your Dodge Dart payments, Nissan and Toyota double down on pickups
Episode #318 of the Autoblog Podcast is here, and this week, Dan Roth, Zach Bowman and Michael Harley talk about Toyota regaining the No. 1 sales crown, getting your friends and family to buy you a Dodge Dart, Barrett-Jackson, and Toyota and Nissan remaining committed to their pickup trucs. We wrap with your questions, and for those of you who hung with us live on our UStream channel, thanks for taking the time. Keep reading for our Q&A module for you to scroll through and follow along, too. Thanks for listening!
Autoblog Podcast #318:

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.

Watch Nissan prank unsuspecting test drivers with GT Academy

Nissan's reality show/motorsports program, GT Academy, is set to return to Spike TV for its fourth season on Friday, and in anticipation, the Nismo team has issued a new video that gives some of its fans a taste of the racing lifestyle.
It all starts innocently enough, with fans test-driving a 2015 Nissan 370Z Nismo, only to have a sudden stop quickly transforms things into something a bit more exuberant and special. We won't spoil the details, so take a look at the video for yourself, and then head into Comments and let us know what you think.
GT Academy will air on Spike TV, Friday nights at 11:30 PM Eastern.