The 2014 Audi A8 L TDI doesn't let being diesel-powered detract from its luxuriousness, but its improved fuel economy doesn't push it immediately ahead of its competitors.
Audi's A8 is in a tough position, battling crowd-favorite luxury flagships like the BMW 7 Series, Mercedes-Benz S-Class and Lexus LS, which you can compare here. Last redesigned for the 2011 model year, for 2014 the A8 takes a big step toward saying "Hey, look at me!" with unparalleled fuel economy in its class thanks to a new diesel engine. Compare the 2014 to the 2013 here.
Diesel is a dirty word. It's not what most buyers expect a luxury automaker to shove under the hood of its flagship car, though Mercedes-Benz and Audi have been selling clean-diesel models in the U.S. for years now. (A diesel version of Mercedes' redesigned 2014 S-Class is also on its way.) The A8 will see minor changes soon, with a refreshed 2015 model showing up overseas first.
The 2014 A8 L TDI is available only in extended-wheelbase L versions, with a huge backseat, standard all-wheel drive and an EPA rating of 24/36/28 mpg city/highway/combined. Pricing starts at $83,395 including a destination charge, and the car I tested came in at $99,445 with options. The A8 L TDI costs $3,700 more than an A8 L with the entry-level supercharged V-6, which is EPA rated 18/28/21 mpg.
Exterior & Styling
With the exception of a small "TDI" badge on the rear passenger side, there's no visual differences to an A8 L TDI — well, except for our tester's massive "TDI clean diesel" stickers.
Audi shot the popularity of LED running lights into the stratosphere; they're now available even on compact cars. But Audi still does it best, and the A8 is a prime example of how to do LEDs correctly. The horizontal LED strips make the front end look even wider, and the headlights themselves are LEDs.
The masculine sedan doesn't show off its chiseled styling very well when painted white, as our tester was. Darker colors better accentuate the A8's sleek body lines.
How It Drives
Luxury-car owners don't want to hear typical diesel engine clatter, feel harsh vibrations through the seat and steering wheel, or poke along the road like there's a mouse turning a wheel under the hood. That's why automakers are continually stepping up their diesel game in the U.S. with additional refinement and bigger fuel-economy numbers. That's especially apparent in diesel-powered luxury cars from Audi and Mercedes.
The A8 L TDI offers one of the most seamless diesel experiences I've ever had, with as few vibrations as a gasoline car. Good luck knowing the engine is even running when the windows are up. None of the A8's luxuriousness is taken away because it sucks up diesel instead of gasoline; the engine is quiet at idle and emits a strangely powerful, non-diesel soundtrack during heavy acceleration.
The turbocharged 3.0-liter diesel six-cylinder makes 240 horsepower and 406 pounds-feet of torque. It's the huge torque — helped by an eight-speed automatic transmission — that moves this 4,500-pound, extended-wheelbase land yacht effortlessly. Acceleration is brisk and buttery smooth, as you'd expect from a luxury car, though passing at 60 mph doesn't have quite the punch it does at lower speeds. Audi says zero to 60 mph comes in a very believable 6.4 seconds, which is the slowest A8 by almost a full second, though not pokey by any means. Of course, the main highlight of the new diesel engine is fuel economy. The A8 L TDI doesn't disappoint, with big EPA estimates — its 28 mpg combined rating is the same as a four-cylinder Toyota Camry — that are repeatable in the real world. I drove the A8 347 miles in mixed conditions and returned 29.8 mpg, with speeds averaging 30 mph. Highway speeds, though, are where the A8 L TDI hits its mileage sweet spot; while cruising at 65 mph, I easily reached the highway rating of 36 mpg. Rush-hour traffic is a different story; I averaged an abysmal 15.1 mpg on a drive that took an hour and nine minutes to travel 11 miles, averaging 9 mph. Thanks, Chicago Marathon.
Audi took a stab at making the A8 L TDI a large, athletic sedan instead of simply a luxury sofa on four wheels, with mixed success (Lexus is fully dedicated to the sofa-on-wheels approach). The A8 is more at home when leisurely cruising all 856.8 miles of its projected range on the highway rather than carving corners. A standard air suspension with adjustable firmness and ride height does its best to give the A8 athletic handling in its most aggressive and sportiest Dynamic driving mode — three adjustability settings of Comfort, Automatic and Dynamic are available. Our tester had the base air suspension, though a Sport air suspension is optional. The big sedan isn't totally useless on off-ramps in Dynamic mode, with well-controlled body motion and good grip from the available 20-inch wheels and no-cost optional summer tires. That said, I'd gladly skip those wheels and tires for a suppler-riding wheel and tire combo that hopefully wouldn't thwack as much over rough roads.
This ain't Audi's dainty (comparatively speaking) 3,858-pound S4, and the A8 L TDI's 4,564 pounds become obvious once you start throwing around its weight, so I preferred to keep the car in its least aggressive Comfort setting. The experience is completely customizable, with Dynamic, Comfort and Auto settings for individual engine/transmission, steering and suspension calibrations. An available Sport Plus Package dials up the A8 another notch with sport steering, a sport differential and that adaptive sport air suspension.
Boy, did I miss the Audi A8 L TDI's massaging seats when I jumped into a 2014 Hyundai Equus a week later. Hyundai's budget competitor to the A8 and other full-sizers just couldn't sooth rush-hour traffic tempers like the A8's legitimately relaxing massaging seats did for front passengers (they're included in a $4,000 Premium Package). I'll always remember you, Wave setting No. 5.
The rest of the interior has held up well since the car's introduction as a 2011 model. Audi's interiors are top-notch, swaying to the sportier side of design, with fewer classic luxury touches and more high-tech, almost mechanical décor. The A8's striking ambient lighting is more "Tron" than "Cocoon."
Being the L version of the A8, the TDI has enough room to lose a small child in the backseat. Its wheelbase is 5.1 inches longer than a regular A8, which equates to 4.2 more inches of rear legroom. The rear is available with features commonly found up front, like heated rear seats, separate power rear seats, individual climate zones and a dual 10-inch screen with a DVD player option.
Ergonomics & Electronics
Chances are you're not going to use Audi's Multi-Media Interface knob-based system to its full extent the first day, or week, of ownership. The level of customization, tricks, shortcuts and depth of usability is huge. Yes, it's complicated, but once you get acclimated to how the system works it becomes a useful tool that allows you to take advantage of all the A8's systems. Be prepared to open the owner's manual more than once.
The various dynamic driving modes, navigation, drive-assist sensitivity, massaging seats, interior lighting options and more are all accessible through the MMI dial. Minimizing the number of physical buttons with a knob-based system like this has one flaw, though: changing driving settings is slow and distracting. You won't find a Sport or Comfort button on the dashboard or steering wheel that allows you to easily switch between driving modes.
Our tester was fitted with a 1,400-watt, 19-speaker Bang & Olufsen stereo, a $6,300 option. Those in tune with stereos and sound quality should compare the expensive option to the standard 630-watt, 14-speaker Bose stereo to see if the B&O is worth the cost. To my ears, the B&O has lost its wow factor since the first S8 I tested with the system back in 2007. Bailing on the B&O may be an easy way to stay in budget considering it's nearly the price of an entire decade-old A8.
Cargo & Storage
The A8 L's long wheelbase doesn't translate to a massive amount of cargo space. A measly 13.2 cubic feet of trunk space is less than what a compact sedan like the 2013 Hyundai Elantra offers, at 14.8 cubic feet. It's considerably smaller than the LS 460's 18.0 cubic feet and the 7 Series' 17.7 cubic feet. You'd expect a large trunk from such a large sedan, but the A8 doesn't deliver. Nor does it have folding rear seats, though there is a pass-through.
Safety & Reliability
The A8 hasn't been crash-tested by the Insurance Institute for Highway Safety or the National Highway Traffic Safety Administration.
An optional Driver Assistance Package, for $3,250, includes Audi's lane assist to keep the A8 from drifting out of its lane, plus a pre-sense plus system that automatically brakes if a collision is imminent and much more. Audi's blind spot warning system is included with the $4,000 Premium Package as well that also includes ventilated front massaging seats.
German luxury cars don't have a reputation for being reliable. The A8 received a rating of four (out of five) in J.D. Power and Associates' predicted reliability analysis. It has not been rated by Consumer Reports. The fact that the A8 is filled with gadgets doesn't bode well for its reliability, as that's often lower when there's more stuff to break.
Audi as a brand, however, is quickly climbing Consumer Reports' reliability charts, moving up four places in one year to be ranked the fourth-most-reliable automaker overall in Consumer Report's October 2013 report, in which subscribers rated 1.1 million vehicles. While Audi was fourth, two other luxury automakers ranked first and third: Lexus claimed the top spot and Acura came in third.
Value in Its Class
The A8 L TDI showcases what clean diesels are capable of, with a nearly seamless driving experience and Camry-like fuel economy. Getting 28 mpg combined, Fueleconomy.gov says it's possible to make up the $3,700 premium you'll pay for the diesel (versus the base engine) within seven years; as of November 2013, the site put annual fuel costs at $2,050 for the TDI and $2,600 for the supercharged V-6. That's assuming you'll drive 15,000 miles a year, 45 percent on the highway and 55 percent in the city. If you drive purely on the highway, you could make up the cost more quickly. The A8 TDI's engine does require regular refilling of the AdBlue diesel exhaust fluid, a fluid used to keep the diesel emissions clean. Recommended intervals are at 5,000 miles, 15,000 miles and then every 10,000 miles, according to an Audi representative.
The bigger question is, how important is fuel economy to luxury drivers who are buying or leasing an $80,000 luxury sedan? The pricier Lexus LS 600h L hybrid has nominal mileage benefits over the base LS 460 L, but it's one of the quietest cars on the road thanks to its almost silent powertrain. The A8 L TDI trounces the LS 600h L's fuel economy, but great fuel economy doesn't increase the A8's trunk size or make the MMI system any easier to learn.
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