Photo: Chevrolet

• Power Plant: 462-kW (620 hp) supercharged 6.2-L aluminum V8 • Transmission: Close-ratio 6-speed manual; dual clutch • Claimed Fuel Efficiency: Information not available • Claimed CO2 Emissions: Information not available • More: Chevrolet is very proud of the fact that the ZR1's power-to-weight ratio is better than that of the Ferrari 599, the Lamborghini LP640, and the Porsche 911 GT2.

Ferrari performance at one-third the price

In some ways, it's the antithesis of advanced sports-car design. It's got an engine up front, with only two valves per cylinder, and those valves are opened and closed with pushrods, just as they were in engines a lifetime ago. Parts of the body are made of fiberglass, a distinctly old-fashioned material compared with the aluminum, magnesium, and carbon fiber used by the Corvette's competitors.

And yet, the Chevrolet Corvette ZR1 does one thing very well: it carries two people as fast as possible, whether on straight or winding roads. The Corvette is the only U.S. volume car with ceramic brake rotors and a polycarbonate window in its hood that gives a peek at the intercooler. Chevrolet's goals are simple: maximize power, minimize mass.

Developed under the code name Blue Devil, the ZR1 is built around a 6.2-liter aluminum V8 developing 462 kilowatts (620 horsepower) of power and 807 newton meters (595 foot‑pounds) of torque. The aluminum block has the dimensions of the classic Chevrolet small-block V8, but this one is hand-built at a special engine shop with processes used only for racing engines. For instance, a deck plate is installed on the aluminum block, to simulate the pressure and minute dimensional differences created by the cylinder heads, before the cast-iron cylinder liners are pressed into it.

A Roots-type supercharger crams air into the engine via an intercooler, providing a denser dose of oxygen that's nevertheless cooled down enough to fend off power-sapping premature combustion. Like most supercharged engines, it can deliver close to peak power over a wide range of engine speeds, from about 2500 revolutions per minute to 6600 rpm.

To handle all that power, the clutch uses a pair of smaller discs rather than the single plate of other Corvettes. This spreads the torque over a greater area and reduces inertia by 25 percent, letting the engine spool up or down more quickly. As with the highest-performance German cars, the ZR1's brake rotors are made of ceramic silicon carbide reinforced with carbon fiber, which is less susceptible to the friction-induced changes that can cause brake power to fade temporarily after repeated high-speed braking.

Ride control on the ZR1 employs a suspension of magnetic particles in a fluid instead of mechanical shocks. The viscosity of the fluid changes in response to a magnetic field, which varies every millisecond in response to inputs from sensors providing data on speed, suspension, and road surface conditions.

The roof, hood, front fenders, rocker panels, and some smaller parts are made of carbon fiber instead of steel, and the weight saved offsets the heavier engine. The car weighs just 1520 kilograms (3351 pounds).

Chevrolet hadn't released performance data by press time, but it said the ZR1 is expected to be the first production Corvette to exceed 320 kilometers per hour (200 miles per hour). It's rumored that the car accelerates from 0 to 100 km/h (62 mph) in less than 3.5 seconds. The factory did confirm that the cornering grip is more than 1 g—enough to make you feel twice your weight in a perfectly banked curve. That's among the highest g-forces of any production vehicle today.

At roughly US $100 000, the ZR1 bests cars costing two to four times as much. It's the only U.S. vehicle that routinely competes successfully in the fabled 24 Heures du Mans race, better known as Le Mans—heady company indeed for a car from Kentucky.

Photo: Audi

• Power Plant: 110-kW 1.4-L turbocharged fuel-stratified injection engine; 30-kW electric motor • Transmission: S-tronic 6-speed Direct-Shift Gearbox, a pairing of two manual gearboxes • Claimed Fuel Efficiency: 4.9 L/100 km (48 mpg) in mixed-mode operation • Claimed CO2 Emissions: 112 g/km • More: Minus the hybrid, the Metroproject is likely a preview of Audi's upcoming A2 subcompact.

A plug-in hybrid with its own mobile phone—and then some

This small and handsome Audi concept contains a surprise that wowed the gadget lovers at the 2007 Tokyo Motor Show: the removable “Audi mobile device,” which combines elements of the iPhone, a key fob, a media player, and a wireless security monitor.

You can make phone calls, view maps, listen to music, and watch videos on the bright red device, but you can also unlock the car, ensure you locked the doors, start the engine remotely (to warm it up on a cold day), and view what's going on inside the car via an interior camera (in case the kids—or thieves—take it for a spin).

The Metroproject is one of several European concept cars this year equipped with a plug‑in hybrid-electric power train. Here, a lithium‑ion battery pack provides an electric range of up to 100 kilometers (62 miles) at a top speed of more than 100 km/h. The 1.4-liter engine cuts in when the battery's charge falls below 20 percent of its maximum.

Multihole injectors deliver fuel directly into the combustion chambers, and the turbo has been tuned to deliver power across the range of engine speeds. This arrangement minimizes the “turbo lag” that usually comes when the turbocharger spools up to a speed that's fast enough to compress the air it delivers to the intake manifold. Audi claims that 80 percent of the engine's peak torque is available from 1250 revolutions per minute.

The Metroproject's Quattro all-wheel drive is delivered by a combination of engine and motor. The combustion engine, generating 240 newton meters (177 foot-pounds) of torque, drives the front wheels; a 30-kilowatt (40 horsepower) electric motor, which adds 200 Nm (147 ft-lb), powers the rear wheels.

Audi says the hybrid system provides 15 percent better fuel efficiency than you'd get by using the engine alone. With a top speed of 200 km/h (124 mph) and acceleration from 0 to 100 km/h (0 to 62 mph) in 7.8 seconds, the Metroproject is something of a “performance hybrid”—a concept that so far hasn't proven popular in the United States, currently the largest market for hybrids of all sorts.

Drivers can choose between “efficiency” and “dynamic” configurations, which vary the control settings for throttle mapping, shift points, suspension stiffness, and other systems. Such variable personalities within the same car are another increasingly common feature in concepts (and a few production vehicles). They offer the driver a choice among profiles that combine different settings for the car's various electronic control systems, usually maximizing fuel economy at one extreme and performance at the other.