The Acura RDX launched in 2007 with Acura's first production turbocharged gasoline engine. In place of the six-cylinder units normally found in compact premium SUVs (like the BMW X3) the Acura's turbocharged sixteen-valve four-cylinder whistles while it works.
Although "four-cylinder" has become a buzzword in these days of expensive fuel, the RDX isn't exactly a fuel miser. Its EPA city rating of 17 mpg equals that of the BMW X3, but the BMW is rated at 24 mpg on the highway, an almost ten percent bonus over the Acura's 22.
It's likely that some of the BMW's highway fuel economy prowess is attributable to a six-speed automatic transmission (in place of Acura's five-speed). The RDX's 2.4-liter four offers about the same thrust as the X3's 3.0-liter in-line six: Acura 240 hp, 260 lb-ft; BMW 260 hp, 225 lb-ft.
Both the BMW and the Acura-as well as the Infiniti EX-will have their work cut out for them, as they'll face increased competition this year when the Mercedes GLK, Volvo XC60, and Audi Q5 debut. The RDX, which debuted for the 2007 model year, is well-poised to compete as the only four-cylinder model in the group.
In typical Acura style, it comes very well equipped, offering only one option - a technology package that includes a ten-speaker, 410-watt sound system, navigation with real-time traffic, and Bluetooth. Our fully-loaded test car had a sticker price of $37,755.
The RDX is acoustically proud of its turbocharging; you'll hear the unmistakable sound of its turbo spooling up as you're pulling out of your parking spot. It's never intrusive, but the sound will serve to remind you why the RSX feels a little non-linear off the line. Once moving, turbo lag isn't a big issue, and the Acura will scoot up to highway speeds with the ease and refinement of a V-6. The automatic transmission shifts smoothly in normal driving, though its shifts are a bit rough in manual mode.
The ride quality is very good (especially compared to an X3) at high speeds, but can be a little nervous when trundling around town. That stiffness, however, translates into stable handling and well-controlled body motions.