New 2007 Acura RDX

"There are two vehicles that I know really, really well," Gary Evert says as we pitch the RDX into a downhill left-hander in Mount Tamalpais State Park north of San Francisco. "The RDX and the BMW X3."

There was plenty for Evert, the RDX's chief engineer, to learn from the X3, both from the BMW's achievements and its failures. For example, the X3's six-cylinder engines position it too closely in performance and price to the X5, so Acura decided to restrict its V-6 to the bigger MDX. The RDX instead gets Honda's first production-car turbo engine in the United States. Based on the 2.4-liter unit from the TSX sedan, the new turbo four produces 240 hp and 260 lb-ft of torque.

This engine is a winner, and its debut will prove to be a watershed moment for the hard-core Honda enthusiasts who can rattle off engine codes as easily as their birth dates. Turbo lag barely exists, power delivery is linear and strong, and fuel economy is estimated at 19/24 mpg city/highway. Our test vehicle's engine emitted a low-frequency drone when we decelerated, but Evert assured us that final production tweaks of the ECU would take care of that. After we headed out of San Francisco, the RDX surged through the Golden Gate National Recreation Area's hills with such ease, we actually forgot that there was a turbocharger under the hood.

Acura mates the turbo engine only to a five-speed automatic, but paddle shifters rip off crisp gearchanges. The standard all-wheel-drive system is adapted from the RL sedan. It delivers up to 70 percent of the torque to the rear axle, where it can be diverted entirely to either rear wheel, an effect that is easily discerned if you really push the RDX through a corner. The Acura might not be as sporty as the X3, but its accurate steering and buttoned-down body control are joined by a firm, reasonably supple ride that doesn't beat you up like the overly stiff BMW's does.

The RDX will share its body and chassis with the new Honda CR-V, but it won't share its all-wheel-drive system. The turbo engine also will be an RDX exclusive for now, but it certainly deserves to spread to other vehicles in the Acura and Honda stables.