Audi RS 7 4.0L Turbo V-8 Busts Out of Corral

LAS VEGAS – Don’t be fooled by the seriously suave demeanor of the low-slung ’14 Audi RS 7, the high-performance variant of the 5-door A7 liftback that reached U.S. shores in spring 2011.

Sure, the car cruises the interstate with the near silence of a zero-emission electric vehicle, subjecting occupants to only the slightest road and wind noise.

This is when Audi’s sophisticated cylinder-deactivation system is at its best, depowering four cylinders so seamlessly that an unsuspecting driver might think all eight combustion chambers have gone into sleep mode, starved of fuel while the car sails along on sheer momentum.

It’s at this time the driver may think the 560 horses corralled inside the compact new TFSI 4.0L twin-turbo V-8 have gone missing from the ranch. But a firm kick of the accelerator finds them bolting in unison up the hillside, stirring up a furiously noisy cloud of dust as the rest of the farm animals scurry for cover.

This bucking bronco requires a steady hand on the reins, because he will run hard – well past the stated 174 mph (280 km/h) top speed, according to some independent tests – and is perfectly content in a full-on sprint. From a standstill, the RS 7 can giddyup to 60 mph (97 km/h) in 3.7 seconds, although some media outlets have managed it in 3.4 seconds.

Such is the reality of the curiously bipolar RS 7, a 4-passenger car with exotic speed that achieves real-world fuel economy of 23.4 mpg (10 L/100 km) during a 245-mile (394-km) jaunt through the desert here. It seems this unbridled muscle car is a pussycat at heart.

Not that the A7 (starting price of $64,500) needed a powertrain overhaul. Its “base” 310-hp 3.0L supercharged V-6 is no slouch, having earned Ward’s 10 Best Engines trophies the past five years.

The fuel-efficient play in the A7 is the new 3.0L TDI diesel V-6, offered for the first time this year in the 5-door sportback (starting at $66,900) and boasting a 38-mpg (6.2 L/100 km) highway fuel-economy rating.

Stepping up to the $80,200 S7 model finds a detuned version of the TFSI 4.0L V-8, rated at a mere 420 hp.

One rung upward sits the high-revving $104,900 RS 7 thoroughbred, which is now on sale.

Aluminum/Wood IP: Zoot Suit Effect

All four of these models should help put Audi back in the saddle in the Upper Luxury car segment, which is dominated by the Mercedes S-Class, BMW 7-Series and Lexus LS. Among eight vehicles in the sector, the A7 ranked No.4, ahead of the A8 sedan, in 2013, according to WardsAuto data.

So what does Audi have to lose in taking a chance on a wild stallion like the RS 7? Audi needs this exuberant overachiever to show the world it can run with uber-octane, big-ticket German luxury sports cars from BMW’s M and Mercedes-Benz’s AMG divisions.

Yes, there are aesthetic and functional reasons to like the RS 7, such as the available air suspension for a softer ride, adaptive rear spoiler, optional matte paint, Audi Connect infotainment system, carbon-fiber trim, black Alcantara headliner and Valcona leather with honeycomb quilting on the seats.

Especially distinctive is the beautifully layered aluminum and black wood instrument panel, which combine to create a pinstripe effect, as if from a 1940s Zoot suit. 

But the RS 7’s technical highlight is its spectacular V-8, which makes it Audi’s most powerful RS model ever offered in the U.S.

The engine shares many of its hard parts with the S7 and S8, except the RS 7 gets an additional oil cooler, larger main bearings and beefier connecting rods and pistons. Outlet valves are made of high-strength Nimonic steel capable of extreme temperatures resulting from twin turbochargers capable of 1.2 bar (17 psi) of boost pressure.

The RS 7’s turbochargers have larger turbines, and the compressor wheels are designed with a unique geometry to allow movement of more air.

The 4.0L TFSI V-8 in the S8 sedan has intake air coming from both sides of the cylinder. The RS 7 has a completely unique intake manifold that directs air into the combustion chamber from just one side of the engine, largely to save packaging space.

The RS 7’s cylinder-deactivation system launched two years ago on the Audi S6, S7 and S8 – an accomplishment worth noting given the complexity of integrating the technology on overhead-cam engine architectures. During steady-state cruising in at least third gear, the camshafts will slide sideways, allowing certain valves to remain closed.

On city streets, drivers can expect to be in 4-cyl. mode about 10% of the time, Audi engineers say. But get out on the highway and set the cruise control, and the engineers predict the car will run on four pumping pistons about 90% of the time. The top speed in 4-cyl. mode is 111 mph (180 km/h). Active engine mounts quell any odd vibrations during 4-cyl. mode, and transitions are near-transparent to the driver. It takes two turns of the engine to switch from one mode to the other.

The cylinder-deactivation system, similar to one used by Bentley, helps the RS 7 elude a gas-guzzler tax, which is remarkable considering the car’s prodigious output. Efficiency could be enhanced further with stop/start, which is fast becoming standard on many German luxury cars, but the technology inexplicably is missing on the RS 7.

Could Audi’s cylinder-deactivation system find its way onto a V-6 in the future? The automaker says it’s possible.

Sending power to the wheels of the RS 7 is an 8-speed Tiptronic automatic with a torque converter. A similar transmission appears in the 520-hp S8, but a number of improvements have been incorporated for faster shifts. Eighth gear has a particularly long ratio to boost fuel efficiency.

The RS 7 also comes standard with Audi’s all-new rear sport differential that divides torque to the right or left wheel. In corners, the differential allows the driver to accelerate earlier by sending additional torque to the outside wheel, which improves grip coming out of the turn. A similar torque-vectoring system also appears in the RS5, S4, S7 and S8. The rest of the quattro all-wheel-drive system carries over from the S7.

An engine making 560 hp should make any car feel light, even the big, spacious RS 7, which tips the scales at 4,475 lbs. (2,030 kg) and benefits from a high-strength steel body and aluminum fenders and closures.

Engineers also focused intensely on achieving the ideal exhaust note, which is subdued during highway cruising. Kick ’er in the tail and the RS 7 lets out a howl that is uncharacteristic for Audi but electrifying nonetheless.

It’s not synthetic sound piped into the cabin, either – it’s honest-to-goodness combustion triggering exhaust flaps in the two mufflers for added effect.

Audi will be busy this year launching the all-new A3 sedan and refreshed A8, followed next year by facelifts to the A6 and A7. This summer, production of the R8 supercar will move to a new plant nearing completion in Neckarsulm, Germany. The new R8 will not be due for another three or four years.

But for now the spotlight shines on the RS 7, a mechanical marvel that is equally beautiful and belongs on any top-end shopping list.

As Neil Young once said – saddle up the palomino, the sun is going down.

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'14 Audi RS 7 Specifications