Test drive Audi A6 50 TDI Quattro and BMW 530d xDrive: two on top

Searching for the best of two luxury six-cylinder diesel sedans

Diesel lovers have no doubt that there is no real alternative to fuel efficient, powerful and clean six-cylinder diesel engines in the new car. Audi A6 and Series 5 on BMW. There is only one question left: who is better?

No, we're not going to get involved in the widespread diesel hysteria here. Because both the new Audi A6 50 TDI and BMW 530d have already proven in our own exhaust gas tests that they are not only clinically clean, but also in real traffic. It is noteworthy that back in February 2017 and without the Euro 6d-Temp certificate, thanks to the double purification of exhaust gases, the "five" reached a peak value of only 85 milligrams of nitrogen oxides per kilometer. Even better was the A6, which emits only 42 mg / km. From now on, we can safely focus on the question of what other qualities these two machines can offer.

A brave new world of Audi

Usually we at auto motor und sport do not pay much attention to the appearance of cars, but for the new A6 we will make an exception. What for? Just look at the huge chrome grille, sharp lines and protruding fenders. No Audi has shown such an impressive presence in a long time, at least in the upper mid-range segment. It is very difficult to spot the differences from the big A8 right away.

The easiest way to do this is to look at the back, where OLED-lit games are slightly reduced in size. The new model designation 50 TDI Quattro reveals the A6 as a diesel, but does not reflect the size of the engine as before, but the power level, with 50 denoting a range from 210 to 230 kW. If this seems too weak or incomprehensible to you, you can, of course, order a car without chrome lettering at no extra charge.

Parallels with the top model can also be found in the interior, which looks much more first-class than in the "five". Carefully crafted open-pore wood, fine leather and polished metal form a noble combination of materials that again sets the standard in this class. However, the reason the A6 looks significantly more modern than its predecessor is primarily because of the new, large-size dual-display infotainment system that replaces the old MMI command system. While the upper touchscreen controls infotainment and navigation, the lower one is responsible for air conditioning.

However, not everything new is necessarily a source of grace. Since we are surrounded by smartphones and tablets all day, it is understandable that we want them to be integrated into the car. But unlike the home couch, here I have to concentrate on driving the road in parallel, and the distraction by the deep touchscreens on the center console is unusually strong. Although they react with great speed, accept handwriting, and respond with touch, they cannot be manipulated as intuitively, that is, blindly, as with the old rotation and press controller.

In this regard, improved voice control that understands spoken and dialectal speech brings relief. However, as in the “five”, not all functions in the car are available with it, for example, massage seats (1550 euros) are still outside its range.

Ergonomic redundancies in the top five

The BMW model has a different philosophy, displaying visual restraint, excluding the two wide “kidneys” of the radiator grille. Despite almost the same dimensions, it looks more elegant. The internal logic for controlling functions is also different. Rather than forcing the polished world of the touchscreen on the driver, the model offers everything to everyone. For example, navigation destinations can be entered not only on the conveniently located 10,3-inch touchscreen or touchpad on the iDrive controller, but also by rotating and pressing or using voice guidance.

If you also want to be a conductor, you can use finger gestures to control the volume. Plus, the entire infotainment system is a bit sharper. True, driving information is also presented on the dashboard in digital form, but still, the "five" can not offer so many display options and such high resolution as the optional Virtual Cockpit on the A6.

Although the Luxury Line (€ 4150) will comfortably accommodate all passengers in a standard leather interior, the front seats are seated in comfortable seats worth € 2290, and the factory-installed interior dimensions promise even more space than in the A6, the feeling is not the same, especially in the back. ... If the driver is more than 1,85 m tall, the legroom behind the driver is compressed to the level of a compact class. In terms of quality and materials, the BMW model is not quite equal to the Audi representative.

Instead, the three backrests are not only standard (€ 400 on the A6), but can also be folded out of the boot. At an additional cost, the small roof panels are lifted electrically to completely release 530 liters of cargo, which is the same for both vehicles. However, the "Five" has the right to load 106 kg more.

Heavy business limousines

Where this advantage comes from, you can tell at a glance on the scale, because the test BMW weighs 1838 kg with a full tank, which is almost 200 kg less than the Audi model. And it is these weights that are felt in the A6 mainly in motion. True, the engineers deliberately tuned it to more agile behavior, and the test car has an integrated rear axle control system plus a sports differential (only 3400 euros), but all this cannot hide the true weight of the business limousine.

Yes, it turns very spontaneously, and when maneuvering in the city it feels almost as maneuverable as the A3. On a secondary road, however, the A6 is nowhere near as accurate as the A6; it quickly falls into (safe) understeer when cornering or suddenly juts out at the rear end sideways when changing direction quickly. In any case, a person needs to tune in to A2000 for a while. On rough roads, the optional air suspension (€ 20) absorbs long waves very quietly, but when combined with XNUMX-inch wheels, the short articulations penetrate much better for the occupants.

The Five is better at tackling this problem with a € 1090 adaptive chassis and standard 18-inch tires with tall rims; here almost all the sidewalks are "aligned". In addition, in a car from Munich, the driver is a more central figure, which is ensured by the extremely informative steering system and the balanced in-line six-cylinder engine. It needs lower revs to spin its 620 Newton meters. In addition, the optional sports automatic transmission (€ 250), regardless of the driving mode, shifts eight gears not only more vigorously, but also without bumps, so you never feel the need to intervene. In contrast, Audi's eight-speed automatic transmission with torque converter sometimes allows itself long pauses in thought and pronounced weakness when starting off, as it is clearly set for more economical driving.

In this regard, firstly, this is aided by the 48V on-board electrical system, which uses its small amount of energy to turn off the engine when power is not required when descending at speeds from 55 to 160. And secondly, the accelerator pedal vibrates the driver's feet about the approach of the speed limit and it is enough to simply move by inertia without acceleration. These efforts were rewarded with an average consumption of 7,8 l / 100 km in the test, but the lighter BMW consumes 0,3 liters less even without such tweaks.

Audi's driver assistants leave a mixed impression. Rather than gliding quietly and with full support on the freeway and intervening almost imperceptibly like the Five, the A6 looks jittery like a novice driver on its first off-road trip. Lane Keeping Assist constantly adjusts the steering wheel position, makes it difficult to recognize road markings, and cruise control with distance adjustment sometimes reacts late to changing traffic situations.

Overall, the 5 Series offers a more balanced and even cheaper overall package, making the more aristocratic A6 the second winner.

Text: Clemens Hirschfeld

Photo: Hans-Dieter Zeifert