DETROIT—My feet are sore, my back aching, and I’ve just spent most of a day walking the floor of the North American International Auto Show (NAIAS)—basically, so you don’t have to. My first impression was that the green cars were elsewhere, but that would be misleading—nearly every introduction, even when the vehicle was a big, honking V-8 performance car, emphasized fuel economy, weight savings, or some other sustainable virtue.

“People expect efficiency, and this car delivers,” said Dan Leone, a Cadillac executive, after his company’s ATS (above) won North American Car of the Year. Yes, it’s a Cadillac, but with 31 mpg on the highway (rear-wheel drive, with the popular turbo four). When Mark Reuss of GM introduced the Viper-killing 2014 Stingray (bringing back the iconic brand name) he described it as “the most fuel-efficient Corvette,” poised to get something just under 30 mpg.

Not bad for a car with 450 horsepower. The key is lightweight construction and an eight-cylinder engine that becomes a four until you really put your foot down.

Even introducing the rip-roaring, 470-horsepower Grand Cherokee SRT for 2014 (that's a less powerful cousin above), Chrysler pointed out that it has an “eco mode” that makes it 30 percent more efficient. Jeep reports that hitting the button “optimizes the new transmission’s shift schedule and extends the range of Fuel Saver Technology, which deactivates four cylinders when conditions allow. A button on the center stack allows driver’s to engage Eco Mode for improved fuel economy.”

No, neither the Stingray nor the SRT (zero to 60 in less than five seconds) is a “green car,” in any real sense. But they are products of corporations very conscious indeed of the need to get their fleets to 54.5 mpg by 2025. I’m sure most buyers of the SRT will be more likely to hit the “launch” button than access eco mode. But the tech around the edges of these cars makes clear that we’re in a new era in which even the heavy muscle is green (or green-ish).

Related post from the Detroit Auto Show: What if a Cadillac and a Volt had a baby? (From our partner, Treehugger)

Jim Motavalli ( @jmotavalli ) writes about cars, technology and the environmental world to anyone curious enough to ask.

The Detroit Auto Show: Muscle cars with green hearts
detroit auto show report