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.
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.
Four Cylinders Sets the RDX Apart
By the end of this story, you may tire of the Acura RDX-BMW X3 comparison. But Acura clearly had BMW on the brain all through the design process, even though the market for entry-level premium SUVs is about to get more crowded, with offerings from Audi, Infiniti, and Lexus. Acura sensed that BMW confused buyers with too-similar technology on the mid-size X5 (which wasn't all that spacious inside) and the newer X3: a pair of inline, six-cylinder engines.
Nobu Takahashi, the young woman in charge of engineering on Honda/Acura's turbocharging project, developed the 2.3 liter inline-four turbo, which is lighter than, almost as powerful as, and clearly different from the V-6 on the MDX, itself due for replacement at year's end. The turbo-four develops 240 hp versus 253 for the MDX and does 0 to 60 mph in about 7 seconds.
Turbocharging technology used to mean lousy gas mileage, but it's now a way to use a smaller engine for better fuel economy and still have power in reserve. Acura says the 3,968-pound RDX will get about 19 mpg in the city and 24 mph on the highway. The i-VTEC engine meets the California standard for ULEVs— ultra-low emissions vehicles.
Cockpit Controller and Buttons
The RDX has just one option, and it's pretty much a no-brainer for technophiles. The technology package comprises the excellent Alpine-based navigation system with voice recognition; real-time traffic overlays via AcuraLink (a two-way communications that also provides you with information about the vehicle); a rear camera; Bluetooth; a 410-watt, Eliot Scheiner-designed audio system with 10 speakers and a six-disc DVD (audio) changer; and GPS control of the climate control system (more cool air flows to the sunny side of the car). Expect to pay about $2,500 on top of the base price in the mid-thirties; exact pricing hasn't been set yet.
The controller takes a week or two of acclimatization, but it won't seem an ongoing education task the way it is with some others, notably BMW's iDrive. On the other hand, Acura forgot that one purpose of the controller is to reduce dashboard-button clutter, an area where iDrive excels to a fault. I counted 42 buttons and knobs sharing the center console area with the RDX controller. The overhanging top-half of the center console leaves the audio system in shadow, which may be why those 18 audio buttons seemed especially hard to navigate.
Super Audio
The Premium audio system, part of the tech package and tuned by recording industry legend Eliot Scheiner (who's won five Grammy awards), plays audio CDs, DVD-Audio discs, and MP3 and WMA discs. It comes with 10 speakers, compared with seven in the base model. (the base model RDX also plays MP3 and WMA CDs.) In a car in which the audio designer knows where you sit, the center channel adds significant presence to the vocal tracks. That said, some self-proclaimed audiophile reviewers say they find the center channel unnatural.
Even if you don't get the technology package, you get XM Satellite Radio standard, as well as the six-disc changer and MP3/WMA capability. But you get 7 speakers, not 10, and only(!) 360 watts, not 410, and a line-in jack in the console. A $200 dealer-installed iPod adapter that connects via the glovebox is available. In front are two 12-volt power outlets, but the RDX has no 120-volt power; that's usually found in full-size (some might say plus-size) SUVs. The car has no back-seat DVD-player option, but that's not a big problem, since the aftermarket offers a wide variety of players with screens in the roof or the backs of the front headrests, usually for less money than charged by the factory or dealer.
Good Handling for an SUV
Acura's drivetrain technology only begins with the engine. The throttle is drive-by-wire for smoother response. Power flows through a five-speed automatic transmission to all four wheels; you can leave it in Drive forever or use the paddle mounted shifters behind the steering wheel.
On the highway, the RDX was smooth and quiet; on twisty back-country roads, it was comfortable and sure-footed both in wet and dry conditions. Much of the credit goes to Acura's Super Handling All-Wheel Drive. A more aggressive version comes on the Acura RL super-sedan, one of out ten Digital Drive winners. It works this way on both vehicles: Power is distributed according to the driving conditions, not only between the front and back wheels but also between the left and right rear wheels. When you're tracking through a left-hand curve, for instance, extra power goes to the right wheel to help the car through the turn.
Acura says its Advanced Compatibility Engineering, or ACE, helps distributes the forces of a crash to keep the passenger compartment intact. I didn't have an opportunity to verify this feature.
Also Noted
Some thoughts apart from the tech aspects: While I was driving the RDX, riding in the second row of seats, and stowing gear in the back, the RDX didn't feel much smaller inside than MDX, even though it's 7 inches shorter in length, 3 inches narrower, and 3 inches shorter in height. (Those RDX specs, 181 inches long, 74 inches wide, and 65 inches high, are all within an inch of the X3.) The split back seat can be folded to allow for up to three passengers in back, with varying amounts of cargo capacity.
The driving position is excellent. The instrument cluster with three pods is busier than BMW's single cutout; also, it was a bit hard to read the RDX dials in daylight with sunglasses on, or with headlights on in daytime. As with most cars, when headlights are on, the instrument panel is dimmed even if it's still light outside. In a test drive through San Francisco and into Napa Valley, the older X3 (the more powerful X3 3.0i version) held its own on curving roads, but the RDX seemed a bit quicker in straight-line acceleration.
Although Acura hasn't set the RDX's price, note that the car includes a lot that's optional on other vehicles: 18-inch wheels, leather seats, high-intensity discharge (xenon) headlights, rear privacy glass, heated front seats (power vented are not available), a power moonroof, , tire pressure monitors, and a center information-display screen.
The RDX's styling is contemporary, although I had trouble recognizing the "athletic armor" stance Acura talked about. Acura suggests this look makes buyers comfortable if they have to leave it on the street because they don't have garages. Maybe so; or maybe it will be one more new car that gets keyed by street punks. The front grille with deep recesses did seem a bit busy.
Buying Considerations
The market for compact SUVs will double or triple in the next couple years. For now, the leaders are the BMW X3 and Acura RDX. The RDX has more standard equipment and will likely come out several thousand dollars cheaper. Both are fine road machines. Drivers brought up to appreciate minimalist German design touches, especially on the instrument panel, and those who prefer more cylinders, may prefer the X3. The Acura has the better navigation system, traffic overlays, and the backup camera. BMW's iDrive does more; Acura's unnamed controller is easier to use. For driving enjoyment and safety, it's a toss-up; for features and value,the RDX makes more sense.
Acura has built a smaller, cheaper, chock-full-of-technology sibling to the MDX SUV. The cockpit controller works well but doesn't do much to eliminate dashboard button clutter.
The variable-flow turbocharger provides more power without lag. Sophisticated drivetrain. Good navigation system. Reasonable fuel economy.
Confusing array of console buttons (even with cockpit controller). You can't unbundle most options to create a sub-$30,000 SUV.
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