Audi’s midsized A6 has long been a well-regarded luxury performance sedan and this year the German automaker is offering it to the U.S. in diesel flavor.
Counting the extra-potent S6, there are now five A6 variants available, and the 3.0-liter six-cylinder turbo diesel in the A6 TDI quattro Tiptronic might just make choosing between these harder.
If you’ve not noticed, Audi has pushed the diesel agenda of late making the case that American legislation favoring hybrids ought not to discriminate against high-mpg, low-CO2 diesels if they can come close to, or exceed hybrid economy.
Diesels are far cleaner and quieter than they used to be, and we wrote a comprehensive look at this sometimes controversial subject, which you can also peruse here. At any rate, it is a fact that in Europe the cost-benefit equation has made them widely accepted, and Audi is eager to show its TDIs can make sense here as well.
Last summer the company announced the A7, Q5 and this A6 would be made available with the same diesel under the hood to add to its A8 TDI. These are the first of more diesels from Audi to establish a foothold in this market.
The price premium for the A6 TDI is about $2,400 more than the supercharged 3.0-liter V6 quattro gas-powered version. The gas burner has more horsepower than the diesel, less torque, zips to 60 only 0.2 seconds quicker and does not return near the fuel mileage.
So far the A6 diesel’s sales have been modest but maybe that’s because it’s still new, and some people have not yet caught on? In any case, here’s the lowdown:
Turbocharged Direct Injection
Tuned for American roads – and speed limits – Audi’s 3.0-liter TDI uses a smaller compressor to fatten the torque band at the expense of some horsepower as compared to the European version’s state of tune.
Rated output of 240 horsepower at 3,500-3,750 rpm and 428 pounds feet torque at 1,750-2,250 rpm compares favorably to the 3.0-liter gas sibling which pumps out 310 horsepower and 325 pounds-feet torque.
What makes the diesel shine is the extra 103 pounds-feet of torque which hits sooner in the rev band as well. The TDI’s torque has to move a not especially lightweight 4,178-pound curb weight car, but it is plenty potent. Rated 0-60 time of 5.5 seconds is within range for a car in this class. It’s a bit down from 5.3 seconds for the gas version but the TDI’s drivability is excellent.
Power is delivered through a well-matched 8-speed Tiptronic transmission and quattro permanent all-wheel-drive system. The auto trans may be manually over-ridden via paddle shifters in either regular Drive mode or Sport.
Standard wheel sizes are 18 inch, with 19- and 20-inch wheels available. Our car came with 19 inch Pirelli winter tires which provide respectable dry grip and of course superior wet and snow grip.
Audi has put together an eye-pleasing blend of purposeful, sporty, but not pretentious styling. The short overhangs and prominent front “Singleframe” grille blend in with the rest of the design elements to make a car with fetching good looks from most angles.
We did get compliments during our week with the car. This example came equipped with the $2,800 Prestige package option which includes LED ambient lighting, S line exterior trim, Audi side assist, auto-dimming, power folding heated mirrors, and a Bose sound system among other extras.
Coefficient of drag is just 0.28, and the 14.1 cubic foot trunk is spacious.
As true of the exterior, the interior is all A6 with comfortable seats and a tasteful choice of materials. The grainy dark-hued ash trim inlays are handsome, and the MMI fold-up – or retractable – touch screen offers a full complement of controls.
Audi includes 3G+ WiFi as part of Audi connect which is offered at no charge for the first six months, then subscriptions start at $15 per month.
Audi connect also has real-time localized weather, news and live fuel prices; Google Voice Local Search for detailed information about all sorts of things you may want to find. The navigation system relies on Google Earth maps which provide an aerial view of the route.
Our car also had the $2,800 optional Driver Assist package with adaptive cruise control, and stop & go, active lane assist and top view camera.
The heated front seats and four zone climate control made for a cozy interior even in freezing winter weather.
Driving the A6 TDI
The way this worked out, we swapped an A8 TDI with the A6 TDI and so, while these are not direct competitors it gave insights we’d not normally experience, and put focus on things that jump out about the A6 compared to its limo-large flagship big brother.
The A6 is also plush, but a bit more functional as an everyday luxury car with more sportiness in the equation. It’s lighter on its feet, and steering effort is noticeably reduced at low speeds. Maneuvering for the midsized car in tighter confines is less of an issue.
Acceleration is also more brisk as the same engine powers both cars, and the A6 is lighter by an estimated 386 pounds, thus quicker to 60 mph by .9 seconds.
The A6 otherwise swaddles the occupants in a modicum of upper-mid-level luxury. The ride is quiet and damping is smooth.
We’ve heard some testers complain about noise vibration and harshness with Audi’s 3.0 TDI, but concerns may be overblown. If you stand outside with the hood open and engine running, that it’s a diesel is unmistakable. Even with hood closed and at idle the muted clacking sound can be detected but Audi has this one hushed down. It is civil, and not bothersome to our ears at all.
Once on the move, the engine is acceptably smooth, and the note from within the cabin is so toned down as to be nearly imperceptible compared to a gasoline-powered car.
And as mentioned, throttle response is immediate. The torque is satisfying with respectable grunt on tap for passing, or simply getting on down the road in a hurry.
In default Drive mode, the Tipronic does short shift to keep the revs down. The tach on most any sedate drive cycle is often well below 2,000 rpm when in cruise mode, even below 1,500 rpm often enough.
This of course helps with the fuel mileage – that and the fact as a type, turbo diesels are the most thermally efficient internal combustion engines. Also, the Tiptronic’s final drive ratio is the tallest at 2.519:1 among A6 siblings, something it’s able to do thanks to the extra torque. The 3.0T gas version, by contrast, runs at 2.848:1 in top gear.
Observed fuel economy on dry cold roads during an east coast winter was on par with the car’s rated 24 city, 38 highway, and 29 combined. Harder usage will of course waste fuel and 20 mpg or less will be the result. Conversely, a steady legal speed using cruise control can net twice that or a little better.
With its 19.8-gallon fuel tank, the A6 TDI is officially rated at 574 miles range.
The EPA pegs CO2 output at 349 grams per mile.
It is not as efficient as the four-cylinder, comparably sized and much cheaper Volkswagen Passatt diesel, but then the Audi is a luxury car with pretty face and all the trimmings and far greater power and speed potential.
Some have asked the obvious and that is, if this is a nearly $70,000 luxury car, who will care about fuel economy that much?
That’s a valid question, but the answer is some will, and we think it’s a mistake to assume people won’t appreciate the extra economy and range.
Audi thinks there will be more in due time, and if you can get it with negligible tradeoff, if any, why not?
And speaking of trade-off, the A6 is a sure-footed, decent handling car – in so far as we could push it on cold dry roads. Handling, as much as we could test it in wintry conditions, is sure-footed and balanced.
Braking performance from vented front and rear discs – 13.6 inches front, 13.0 inches rear – is confidence inspiring as well.
And as for snow performance, this is a very secure machine. Its all-wheel drive and grippy winter tire combo let it plow through many inches of snow, limited only by ground clearance.
Should You Get One?
The extra sticker price to go diesel is not outlandish, but then you’ll also be faced with more expensive fuel offset by higher mpg. Is it a clear no brainer? Given regional U.S. diesel prices, its fuel economy of 24 city/38 highway/29 combined could pay off, but it would take a while. The TDI’s fuel economy beats that of its 3.0T gas quattro sibling by 6 mpg in the city, 11 mpg highway, and 7 mpg combined.
That makes it a close-but-worth-considering call if only weighing fuel economy, but then, the drivability of this magnificent engine adds to the dilemma.
For typical American driving, having the torque of a big V8 on tap that might also crest past 40 mpg on the highway is a nice combo.
Anecdotal accounts of the robust build of diesel powertrains has lent to a belief by some drivers in their extra longevity. Audi is not willing to make this statement officially compared to its gas-powered variants, but research can find others who vouch safe that TDIs have been durable but this would be still a guess in the final analysis.
More certain is the A6 TDI is a long-legged runner that’s good anywhere and anytime – and it will be fully appreciated in the snow belt regions of the country each winter.
But ultimately, you’d be well served by test driving this one back to back with others to decide how you like it.
Others cars in this echelon to consider include the Mercedes-Benz E-Class diesel, and BMW 5-Series xDrive diesel. Of these two, the BMW has the same displacement and type of engine and all-wheel-drive, and so is closely matched. The Mercedes returns greater economy with a 2.1-liter four-cylinder turbo.
In all, the A6 TDI is a wonderful example of the traditional carmaker’s art. If you have issues with diesel – we know some do but many others do not – then you may want to pass on it.
Otherwise, for those who do appreciate what the diesel version of Audi’s sleek midsized sedan stands to offer, we’ll reiterate that it’s balanced, very satisfying, and a worthwhile addition to the already fine A6 lineup.