Nissan, Toyota hot rods offset by pokey econocars

Car designers are straining their imaginations like never before to be fuel-miserly and earth-friendly, to create vehicles that may be driven with a clear conscience.

Except when they're reverting to form and introducing the latest sexy, gas-hungry hot rod with head-snapping acceleration.

Nissan Motor Co. showed its tiny Pivo2 electric concept car at the 40th Tokyo Motor Show this week. It's equipped with lithium-ion batteries and multidirectional wheels that let the driver park in the tightest of spots.

Pivo2 isn't for sale and may never be. Automakers call cars like this a design exercise, to help test ideas that might show up in future cars. Nissan and other automakers must be ready: Lawmakers worldwide are responding to concerns of global warming with tighter and tighter fuel-consumption standards.

Automakers increasingly are at pains to stay within the regulations and continue to manufacture larger cars and multipurpose vehicles, which by dint of their size, weight and power may consume 50 percent or more fuel than a dinky, plain-Jane econobox.

After years of growing larger and heavier, new models (even gas-electric hybrids and those that burn diesel or a mix of gasoline and ethanol) are bound to get smaller and slower than their predecessors. Consumers might be willing to sacrifice in theory to keep the planet cool. But they won't be happy as they try to cram kids, dog and hockey sticks into cramped backseats or cargo areas.

Designers aren't entirely relinquishing their dreams of creating fast, beautiful, powerful machines. I suspect some are secretly praying for a prolonged streak of cold weather. And maybe they're waiting for someone to prove that warm temperatures aren't caused by human activity and carbon emissions.

Nissan is displaying another car in Tokyo, one slated for production that will win no awards for environmental responsibility. Nissan's all-wheel-drive GT-R is a beauty, powered by a 3.7-liter V-6 engine that develops 470 horsepower and capable of reaching 60 miles per hour (97 kilometers per hour) from a dead stop in less than four seconds.

When GT-R shows up in U.S. dealerships next June, it should sell for roughly $80,000. The price equates to somewhere between half and two-thirds of a Porsche Turbo with similar fire-breathing performance characteristics.