2014 Audi A8L TDI Review

Joining the Q7, which has offered diesel power since 2009, are new diesel versions of the Q5, A6, A7 and their flagship sedan, the stretched-wheelbase A8L. With diesel variants of the BMW 7 Series and Mercedes S-Class still a year away (confirmed for the Bimmer, rumored for the Benz), the A8 is the only large luxury sedan to offer a diesel power – for now, at least.

Open the hood and you’ll find the same 240-hp 3.0-liter turbo diesel V6 employed in Audi’s other diesel models, though the A8’s version produces less torque (406 lb-ft vs 428 lb-ft). From the flywheel back, the powertrain is identical to the rest of the A8 lineup, with an eight-speed Tiptronic automatic and Quattro all-wheel drive, though the A8 TDI’s final-drive ratio is taller (2.642:1 vs. 3.204:1).

On paper, the TDI is the slowest member of the A8 family, if you can call 0-60 in 6.4 seconds slow. For comparison, the A8L 3.0T, with a 333 hp supercharged V6, makes the run in 5.5 seconds. But as we’ve said before, numbers don’t tell the whole story when you’re talking about diesels.

With a broad, flat torque curve that stays high through most of the rev range, the TDI engine delivers an even flow of power whenever you demand it. The torque comes on in a surge that’s a perfect match for the A8’s air suspension and smooth-shifting automatic transmission. Even the acoustics are right: the diesel makes a muted roar under power that is authoritative but not intrusive. We are struck by how perfectly the TDI engine matched the A8’s genteel demeanor.

Though the A8 is designed to deliver a comfortable ride, it’s still an Audi and that means it can hustle through the curves with skill and grace. An optional ($3,500) Sport Plus Package adds a Dynamic mode for the air suspension, which firms up the ride. The Quattro all-wheel drive system bumps up the grip by a notch or two, and as with most Audis, gentle understeer awaits anyone who probes the limits of its handling. We made only a cursory exploration because the A8 really isn’t that sort of car. We spent most of our time cruising at just above the legal limit.

The one thing that really surprised us was the fuel economy. EPA estimates suggest 24 MPG city and 36 MPG highway. Even so, we were shocked at the end of our test week when the trip computer showed 28.3 MPG, just a tick above the EPA combined figure. That’s an incredible number for a car the size of a river barge. How can you not love diesel?

That said, there are a few things about the A8 that we aren’t gushing over. Though we’ve yet to meet an Audi interior we didn’t like, the A8’s is our least favorite, with its secondary controls (including climate, stereo and the MultiMedia Interface (MMI) dial that controls navigation, Bluetooth phone, and various other functions) all crammed into a small space behind the tricky-to-use ratchet-style shifter. Other Audi models we’ve driven make better use of the real estate on the center console.

We certainly won’t complain about the leather-upholstered front seats in our test car with forced-air cooling and a massaging function. They come as part of a $4,000 Premium Package that also includes LED headlights and a blind-spot monitoring system, a curious combination of options if we’ve ever seen one.

Comfortable as it is the A8L also provides good all-around visibility, which makes parking easier. Not that it matters if your option an A8L like our test car, which is festooned with concealed parking cameras that cover the front, back, sides and corners of the A8, allowing us to dock this baby as if we’d had years of practice. The cameras are included in the $3,250 Driver Assistance Package, along with automatic high beams, adaptive cruise control, and lane departure warning. Our car also had the weapons-grade Band & Olufsen stereo that adds a staggering $6,300 to the price (but no extra charge for the resulting tinnitus).

It’s the back-seaters who get the best deal. The “L” in the A8L’s name denotes a wheelbase stretch of 5.1 inches, 4.2 of which is added directly to rear-seat legroom to provide enough stretch-out space for the NBA’s finest. Audi offers a $3,500 Rear Seat Comfort Package that adds heated and power adjustable rear seats with lumbar support, two additional climate control zones for the rear seats and the ability to remotely slide the front passenger seat forward. Obviously, the A8L is intended for people who want to be driven rather than driving themselves.

Pricing for the A8L TDI starts at $83,395 (including $895 for shipping and handling) and ranges up to $119,845 with all the options. That’s a $3,700 increase over the gasoline-powered A8L, a hefty price premium to make up. Using national average fuel prices for April, 2014, and EPA combined estimates, the diesel saves about 4.8 cents per mile over the gas V6, which puts the break-even point just past 77,000 miles. Keep in mind that gasoline-powered Audis require high-octane fuel, so the price difference at the pump isn’t as steep as with most cars. Diesel fuel is also less prone to sudden price spikes than gasoline. The diesel is restricted to the long-wheelbase A8L model, which leads us to believe there was some commercial element in the A8’s product planning. That makes sense: If you take people to the airport for a living, the TDI engine could save you some serious dough over the long haul.

It’s a bit of a shame that the diesel isn’t offered in the regular-length A8 but then again, maybe it isn’t. If you prefer to drive yourself, it might be better to buy an A6 or A7, both of which are offered in TDI form. Both cars are smaller and easier to handle, plus they have a better interior layout. The A6 TDI offers plenty of rear seat space and is significantly cheaper than the A8 at $58,395. The A7 TDI costs another $9,400 over the A6 and gives up back seat headroom, but man oh man, is it ever a gorgeous car – and it’s still less expensive than the A8L.