That whoosh emanating from the Windy City this week comes courtesy of Mercedes-Benz, which threatens to blow the doors off its competitors at the Chicago Auto Show.

The tri-star brand introduces two new additions to its high-performance AMG lineup: the Mercedes ML63 and R63 cross/utility vehicles.

The R63 makes its world debut in Chicago. Based on the robust chassis that supports the Mercedes R-Class CUV, the R63 is billed as a concept vehicle, but expect to see it on dealer lots later this year, a source tells Ward's.

The ML63, which makes its North American debut, will arrive in U.S. showrooms this summer.

AMG 6.3L V-8

Both vehicles are powered by the first engine developed entirely by AMG – a 6.3L V-8 that generates 503 hp.

The auto maker claims the powerplant will deliver 0-60 mph (97 km/h) times of less than 5 seconds in both applications.

And in another milestone, the vehicles mark the return to AMG of Mercedes' trademark 4Matic all-wheel-drive system. It is a timely return considering 4Matic, as a passenger-car technology, is 20 years old this week.

While most U.S. AMG buyers tend to have zip codes in California and Florida, the auto maker lays claim to a “strong contingent” of customers in northern climes. Mercedes expects this demographic will be enticed by the combined appeal of the 4Matic's improved traction and AMG's enhanced power and handling attributes.

Mated to a 7-speed automatic transmission, the new engine gives Mercedes an answer to the Porsche Cayenne Turbo S, which bowed last month at the Greater Los Angeles Auto Show. The new Cayenne, already on sale, boasts a 520-hp twin-turbocharged 4.5L V-8.

The new AMG engine, however, is naturally aspirated. With a peak torque of 465 lb.-ft. (630 Nm), the powerplant has no parts in common with other Mercedes V-8s and its 4.3-in. (10.9-cm cylinder spacing is similarly unique.

Its construction makes extensive use of high-strength silicon-aluminum alloy. Its closed-deck aluminum engine block, which features cast-in-steel reinforcements and a “bedplate” for increased rigidity, has its roots in racing.

The cylinder bores benefit from a twin-wire-arc-sprayed coating – a first for a production engine. The process drastically reduces friction and creates surfaces that are twice as hard as conventional cast-iron cylinders, Mercedes claims.

The new engine has four valves per cylinder, variable valve timing and bucket tappets. Fuel injection, ignition, valve timing and the powerplant's variable intake manifold are managed by a Robert Bosch GmbH ME 0.7 microprocessor.

Four catalytic converters, four oxygen sensors, secondary air injection and double-wall exhaust piping handle whatever emissions are not mitigated by the variable valve timing and the exhaust gas recirculation that occurs at part throttle.

The 7-speed transmission features three shift modes: sport, comfort and manual. And it can be controlled with a Direct Select lever mounted on the steering column, or with F1-style paddles on the steering wheel.

Both vehicles feature Hill-Start Assist and a double-wishbone front suspension and 4-link rear suspension, supplemented by a height-adjustable Airmatic air suspension system, AMG-tuned shocks and an adaptive damping system specially configured to accommodate performance driving.

Styling cues include an AMG grille, flared fenders and AMG side skirts.

Inside, the vehicles feature Nappa leather AMG sport seats with alcantara inserts in the shoulder bolsters.

An AMG version of the S-Class sedan remains in the queue. But the redesigned car is represented in Chicago by the 510-hp S600, which made its North American debut last month at the LA auto show. (See related story: Brake Lamp System Flash of Brilliance)

emayne@wardsauto.com