Acura RDX : The sports car of crossover SUVs.

What's old is new again. Acura gave the century-old technology of turbocharging a new twist in the RDX, an appealing small SUV with a wealth of technology goodies, all aimed at toppling the BMW X3 from its perch.

Announced June 1 and due in dealer showrooms by late summer, the all-wheel-drive RDX may be the ideal vehicle for the urban dweller who weekends in the country with friends and spends occasional time on unpaved or snow-covered back roads. The RDX falls into what's being called the "entry premium SUV market," meaning cars that are bigger and more luxurious and have more technology than a Toyota RAV4, and are smaller and cheaper than the Acura MDX or BMW X5. Buyers of these $30,000-to-$40,000 vehicles are looking for a big dose of technology, and the RDX has it.
Turbocharging for Power, Economy

This is the first foray into passenger-vehicle turbocharging for Acura and its parent company, Honda. Though turbocharging dates back to 1905 and a Swiss engineer named Alfred Buchi, Honda/Acura made a major technological advance in reducing turbo lag and increasing performance with its variable-flow turbocharger.

Acura RDX

Turbocharging uses the pressure of engine exhaust to force more air into the engine intake flow: Step on the gas, and an impeller in the exhaust manifold spins faster, as does a second, connected impeller in the intake manifold. Acura overcame turbo lag, the roughly one second of hesitation that occurs while the impeller spools up to deliver max power, with a flap that varies the flow into the impeller, and did it in such a way that the hinge isn't directly in the way of the superheated exhaust gas (which is 1,000-plus degrees). This is a simpler solution than, say, using a small turbocharger that spins up quickly but doesn't deliver a lot of power, plus a second, big turbocharger for high rpm power.