Used 2014 Audi A8 Diesel Review

The 2014 Audi A8 remains a top pick among large luxury sedans thanks to its impressive performance, comfort, high-tech features and impeccable build quality.

what's new

For 2014, a diesel V6 joins the A8's engine lineup. Additionally, certain option packages have been reshuffled and renamed, and all Audi A8s now have standard keyless ignition and a power-operated trunk lid.

vehicle overview

Audi has typically trailed its Teutonic rivals in the luxury-car sales race. However, as the 2014 Audi A8 illustrates, this sales ranking should not be construed as a reflection on the relative quality of the manufacturer's products. With a gorgeous cabin and handling that's distinctly and gloriously German, the A8 is, from roof to rubber, a class act that succeeds at elevating the driving experience in the large luxury sedan class.

Audi tweaked the formula last year by revamping its engine lineup for the full-size A8. For the first time, base models were powered by a V6, and that switch has proven to be quite satisfying from a performance and efficiency standpoint. A new turbocharged V8 also debuted as a midlevel choice. Now for 2014 the engine lineup sees another change, with the addition of a 3.0-liter diesel V6. Performance is quite satisfactory, with a 0-60 mph time of 6.3 seconds along with fuel economy that's the most frugal in the high-end luxury sedan segment: 24 mpg city/36 mpg highway and 28 mpg combined.

Within and without, the A8 embodies deluxe sophistication. The materials in its cabin are top-rate, and evidence of superior craftsmanship abounds. Typical of the large luxury sedan class, there are two wheelbases available, with the longer "L" model providing extra rear legroom. You can add further decadence to the rear seat with a variety of options, including massaging rear seats or an extendable footrest in W12 models. Other draws to the A8 include standard all-wheel drive and an extensive collection of luxury and technology-oriented features.

Of course, most of these are traits that are shared by the A8's rivals, and selecting just one of these excellent luxury sedans is bound to be a challenge. Buyers with a yen for a sportier driving experience will want to check out the 2014 Porsche Panamera. If full-on luxury is more your thing, consider the sumptuous, all-new 2014 Mercedes-Benz S-Class. There's also the Jaguar XJ if you find the A8's styling a bit too anonymous, along with the BMW 7 Series, a perennial favorite even though it's now among the older models in this class. Still, despite fierce competition, the A8 is a great choice for buyers who appreciate understated opulence and a balanced approach to luxury and performance.

performance & mpg

Powering the base model 2014 Audi A8 is a supercharged 3.0-liter V6 that produces 333 horsepower and 325 pound-feet of torque. All of this power is channeled through an eight-speed automatic transmission and all-wheel drive. In Edmunds testing, a long-wheelbase L 3.0T with the optional Sport Plus package accelerated from zero to 60 mph in 5.3 seconds, which is quicker than every V6-powered competitor and just off the pace of those packing V8s.

Also standard on the V6 is an automatic stop-start feature that shuts the engine off when the car comes to a stop. It helps to increase fuel economy, which is quite good for this class of car at an EPA-estimated 21 mpg combined, (18 mpg city/28 mpg highway). The same numbers apply to the long wheelbase.

Newly added this year is a 3.0-liter turbodiesel V6 engine rated at 240 hp and 406 lb-ft of torque. In our testing, an A8 TDI took 6.3 seconds to accelerate to 60 mph. At 28 mpg combined (24 mpg city/36 mpg highway), fuel economy with this engine is exceptional, and the engine comes only with the long-wheelbase configuration.

The turbocharged 4.0-liter V8 produces 420 hp and 444 lb-ft of torque. Stop-start, an eight-speed transmission and all-wheel drive are also standard. In Edmunds testing, an A8 L 4.0T ran to 60 mph in just 4.2 seconds. The EPA estimates the 4.0T should earn 21 mpg combined (17 mpg city/28 mpg highway), or nearly the same as the supercharged V6. The L 4.0T is only slightly more thirsty at 19 mpg combined (16 mpg city/26 mpg highway).

Audi A8s with the 6.3-liter W12 engine come only in long-wheelbase configuration. The 12-cylinder engine makes 500 hp and 463 lb-ft of torque. As with all A8s, an eight-speed automatic and all-wheel drive are standard. Weighing in about 200 pounds more than the L 4.0T, the A8 L W12 will reach 60 mph in 4.4 seconds, according to Audi. The EPA estimates fuel economy at 16 mpg combined (13 mpg city/21 mpg highway).


Standard safety equipment for every 2014 Audi A8 includes antilock brakes, stability and traction control, full-length side curtain airbags, front and rear seat side airbags and active front headrests. A rearview camera is standard on most A8s, while the W12 gets an enhanced camera array with a top-view display (optional on lesser models). A blind-spot monitor and lane-departure warning system are offered in a couple of available option packages. Also optional is Pre-Sense Plus, which uses the adaptive cruise control system's radar to monitor traffic and alerts the driver if a potential collision is detected, even applying the brakes (to a standstill when vehicle speed is below 20 mph). A night-vision camera is a stand-alone option.

In Edmunds brake testing of a V6-powered A8 with optional summer tires, the car came to a stop from 60 mph in an impressively short 104 feet. With the same tires, the TDI model needed only 109 feet. An A8 3.0T with all-season tires delivered us to a stop in 121 feet, which is average for similarly equipped cars in the class. An A8 L 4.0T with all-season tires came to a stop from 60 mph in 114 feet.


Power from the Audi A8's base V6 is plentiful, whether under acceleration or cruising down the highway. Passing slower cars is effortless and the brakes are equally up to the task of bringing the big sedan to a halt. The 4.0T power plant is even more impressive. While earning nearly the same fuel economy as the supercharged V6, the turbo V8 delivers a tidal wave of effortless torque to the point that a V8-equipped A8 will go toe to toe with almost any muscle car in a drag race.

Fortunately, there are few if any drawbacks to making the switch to the diesel-powered A8 TDI model. Acceleration is brisk thanks to the plentiful torque, and there's very little diesel clatter to be heard from the inside. The automatic stop-start function can be a little jarring on startup, but it is quick to react and requires no waiting to get back on the gas. For those who find it too disruptive, it can be disabled easily.

With its all-wheel drive, well-tuned suspension and crisp steering response, the A8 handles like a smaller, lighter sport sedan in either wheelbase configuration. Yet over broken pavement, the Audi flagship delivers a compliant, composed ride fully in keeping with its luxury sedan status. We also like its electronically adjustable settings for the chassis and engine calibration, which provide a much greater degree of driver customization than BMW's similar system.

All things considered, the 2014 Audi A8 is a worthy competitor among world-class luxury sedans. While the gap between these high-end sedans is narrow, the Audi A8 distinguishes itself as a bona fide driver's car.


As Audi's flagship, the 2014 A8 represents the best that the company has to offer. Thanks to exquisite materials combined with impeccable craftsmanship, the cabin is one of the finest in any flagship luxury sedan.

As you'd expect, comfort is a priority and the A8 delivers it in heaping portions. The upgraded seats found in the Premium package adjust in so many ways that Audi needed to invent a more advanced means of controlling them, and they ultimately ensure that drivers of any size or shape will find an optimal position to motor away countless miles. Rear seat comfort is also noteworthy, especially in the long-wheelbase versions that provide an expansive 43 inches of rear legroom.

For technophiles, Audi's Multi Media Interface provides a long list of functions through a crystal-clear display. There's a bit of a learning curve to it, but with a little time, control of numerous systems becomes second nature. The unique remote touchpad (upon which you can "write" numbers and letters with your finger) also doubles as a radio preset panel. It may seem like a superfluous novelty at first, but it turns out to be as useful as it is cool.

If there's one complaint that seems to come up more than others, it would be the A8's lack of trunk space. At a paltry 13.2 cubic feet, cargo capacity is far below that of its competitors and not nearly adequate to accommodate luggage for four adults.

edmunds expert review process

This review was written by a member of Edmunds' editorial team of expert car reviewers. Our team drives every car you can buy. We put the vehicles through rigorous testing, evaluating how they drive and comparing them in detail to their competitors.

We're also regular people like you, so we pay attention to all the different ways people use their cars every day. We want to know if there's enough room for our families and our weekend gear and whether or not our favorite drink fits in the cupholder. Our editors want to help you make the best decision on a car that fits your life.