V8 all-wheel drive station wagons in a 1,820 hp showdown

Many moons ago, someone invented concentration as an electronic stability control for human thoughts. It’s a shame, however, that only a few people can find the on/off button. For most, external influences trigger activity or inactivity, a feeling of safety, of security even, as now at over 250 km/h in the RS 6 Avant on the parabolica of the Hockenheim F1 circuit. The mildly hybridized four-liter V8 engine revs above 6,200 rpm in fourth gear, already sucking the hairpin from the horizon.

Here’s a vague impression of the vehemence with which the cross-stabilized RS 6 presses through corners.

You know by now about the impressive deceleration performance of the braking system, which consistently delivers values around 11.4 m/s², courtesy of the massive tires, 285/30 R 22 all around, hell another one. The assembled tuning guild of the 1980s would faint collectively in the face of this dimension. In any case, behind the wheel you don’t think about how you’re going to brake the tricky hairpin bend to the exact centimeter.

In an R8, on the other hand, you wouldn’t be thinking about anything else, while the V10 engine behind you would be screaming its head off. The 600-hp powerplant pounds with appropriate fury, while you consider stopping by the furniture store at the nearby interchange on your way home. The daughter needs a desk, school enrollment is looming. The cargo space holds a maximum of 1,680 liters, the smallest in this comparison (BMW Alpina: 1,700 l; Mercedes: 1,820 l), but it’s usually larger than the daily requirements.

Comfort truck? No!

This daily need usually ranges between the extremes of racetrack and furniture store, although each of the three station wagons should be able to cover everything. And for that, Audi packs the RS 6 quite full – no, not the cargo space, but the rest.

Audi RS 6 Avant, Exterieur


Audi wants to know what it’s talking about and has fitted the RS 6 with 22-inch wheels with 285 tires under the chubby cheeks.

The engine is supplemented by a belt starter generator, which, however, is not intended to boost, but rather to recuperate with 8 kW in order to switch off the engine as often as possible in push mode (for up to 40 seconds), efficiency and all. At low load, however, it shuts down four cylinders (numbers 2, 3, 4 and 8). The V8 has to boost all by itself, but it develops 800 Nm at just over 2,000 rpm, which the eight-speed automatic transmission channels in such a way that the force of the acceleration is highly impressive at all times, but does not reflect the drama of the looks. Does the chassis cope with all this? In short: yes. Long: The RS 6 once again uses the principle known as DRC of adaptive dampers connected diagonally via oil lines (three characteristic curves), steel springs, the sport differential (distributes power between the rear wheels) and all-wheel steering.

Still all the masses in the cupboard

With a weight distribution of 55.2 to 44.8 percent, the fourth generation of the power station wagon remains at the moderate level of its predecessor, with BMW Alpina and Mercedes-AMG placing slightly less load on the front axle. In any case, the entire technology ups the driving character of an A6 Avant to a formidable agility quiff. Especially on the country road, the Audi gets close to its driver, who sits a bit too high on the gripping sports seats.

Audi RS 6 Avant, BMW Alpina B5 Touring, Mercedes-AMG E 63 S T, Exterieur

Three V8 biturbo engines, three characters: from unobtrusive and thrusty (RS 6) to greedy and committed (B5) to angry and fiery (E 63).

But otherwise: hui! Audi can even get a handle on the steering feel if they want to. Despite the progressive gear ratio, the even steering force build-up is pleasing, and there’s a good balance between committed steering and sufficient composure at high speeds. Meanwhile, the chassis bravely spreads the Avant into the curves, stabilizes, guarantees a high level of driving safety, and occasionally gives the impression of a lively rear end, because up to 85 percent of the power can reach the rear axle.

However, none of this translates into the best measured values, neither in the driving dynamics disciplines nor in longitudinal acceleration, where the RS 6’s highest mass of 2,172 kilograms puts pressure on its temperament. Not even in consumption, despite the mild hybrid system. That at least counts as standard equipment, all the other mentioned technology components don’t, which still lifts the Audi’s price above the, well, self-confident level of the Mercedes. But now, shortly after the hairpin in Hockenheim, the concentration is back, right turn, keep it on, through, don’t turn into the engine flow on the brakes (otherwise it will come across), accept slight understeer, accelerate early.

BMW Alpina B5 Touring, Exterieur

Typical Alpina: Handling like a rear-wheel drive car with plenty of grip.

Into the pits, the BMW Alpina B5 Biturbo Touring is waiting. It’s nice that it’s waiting there, but it wouldn’t have to be. After all, the B5 doesn’t see itself as a replacement for an M5, the Touring variant of which BMW continues to refuse. But even before you reach the exit of the pit lane, you start to doubt the comfort-focused orientation of the small-series manufacturer’s products.

Your right foot tries desperately to shake the 4.4-liter powerplant off the sole, so much does it stick to it, more than the other two. Alpina modifies the BMW V8’s intake and exhaust air ducting, increases cooling capacity, and installs a so-called crosstalk between the intercoolers to minimize pressure pulsations. More?

Sure, the ZF 8HP76 eight-speed automatic gets fine-tuning, also works with identical strategy regardless of the driving mode. Only when the driver moves the selector lever to “S” do the shift points shift. As now, therefore, full concentration, the cerebral ESP works, because you neither expect the immediacy of the thrust nor its still easy dosage. What an engine! 608 HP! It certainly pulls the color out of the coat of the stubborn brown cattle of Alpina’s Allgäu home, piling up a torque mountain of 800 Nm at 2,000 rpm, whose peak plateau only drops at 5,000 rpm.

Audi RS 6 Avant, BMW Alpina B5 Touring, Mercedes-AMG E 63 S T, Exterieur

12.7 l/100 km Super Plus is enough for the BMW Alpina in the test average, the competitors need around 0.5 liters more. Besides, the B5 is the fastest of the trio with up to 322 km/h.

If already, run already

The sound? Present, warm basic tone with slightly rough nuances, strong character, never obtrusive – splendid. At 2,085 kilograms, the unit, which is charged at 1.4 bar, has to haul a comparatively light lump, and it immediately translates this into the best longitudinal acceleration, at least up to 200 kilometers per hour. Above that, the restless Mercedes-AMG would be ahead, my goodness, but only the BMW Alpina runs without a limiter, up to 322 km/h. It also does a great job with the double lane change. It remains more stable and drives faster than the upgraded Audi, which is too loose with the rear end. However, where a bit more looseness would be good, the B5 seems too cramped.

Basically, body movements don’t necessarily have to soften the handling. Load point shifting, you know. The B5 struggles here more with a somewhat too pronounced roll tendency, which overtaxes the cornering outer front wheel; possibly the rear axle lock (optional; locking degree 25 percent in pull and push) then pushes a bit too much in tight turns. In any case, the Touring lacks the outrageously natural agility of the other two trunks – yes, that’s what they are, and that’s precisely what makes them so appealing.

Because, just between you and me, the Alpina doesn’t drive slowly. Even if you let it fly on the racetrack, others have to stretch quite a bit. The brand’s typical talent comes to the fore especially in the wider bends, with self-steering behavior like that of an extremely high-grip rear-wheel drive car – despite all-wheel drive.

BMW Alpina B5 Touring, Interieur

Low-mounted, cozy seats and the best suspension comfort in the comparison characterize the interior of the B5.

Steering task

The steering feel is a bit milky, even the RS 6 offers a more solid feedback, the E 63 S anyway. The holding forces and steering force buildup of the integral active steering are just right, finely balanced and homogeneous. By the way: The maximum steering angle of the rear wheels is a moderate 2.5 degrees on the B5, twice that on the Audi (in the opposite direction at low speeds). The Alpina wants to compensate for its slight deficits in agility with a high level of suspension comfort, which it achieves very well with its balanced set-up applied to one wheel dimension.

The specific adaptive dampers have the widest spread in their three characteristic curves, of which the middle one (Sport) best suits the Touring’s thoroughly dynamic nature. It noticeably reduces body movements on long waves, while short ones come through a bit more binding, but fizzle out in the low-mounted, thickly padded BMW comfort seats.

Because of the extensive adjustment options, these are actually among the best car furnishings currently available, but in this environment there is a lack of lateral support. The driver’s door of the Mercedes-AMG swings open and you drop into the optional bucket seat, which has no problem at all with lateral support. Not even with the seat depth, but rather with the upholstery. No matter. Wasn’t there a slight smacking sound just now, as if the E was sucking you up, laminating into itself?

Mercedes-AMG E 63 S T, Exterieur

If the front axle is released from the drive force transmission via drift mode, that’s exactly what happens, because: 850 Nm.

From this perspective, you assume everything, for example that the DTM race is about to take place on the Singen street circuit or the Diepholz airfield and that the name “R. Asch” or “Fritz K.” (Kreuzpointner, the last name was too long for the window of his racing Benz-190) is stuck on the rear side windows. Not, however, that a gymnasium opens up behind you, in which a cuboid measuring 1,640 x 920 x 670 millimeters can be effortlessly sunk.

And the E 63 S doesn’t let you feel this viciousness, romping off impetuously. A bit too impetuously, perhaps, because the B5 manages it with identical intensity, but without the powerful shoulder thrust. In addition, the nine-speed automatic transmission with wet starting clutch stumbles awkwardly through the gear pairings every now and then, especially when pulling away.

Otherwise, nothing stumbles in the 612-hp T, which demands concentration with its race car-like quality, its latent hardness, its bristliness that extends far beyond the suede-covered steering wheel. The rear axle, which has been redesigned compared to the base model (new axle and wheel carriers, special stabilizer bar and differential connection), contributes to this, as does the entire chassis set-up, including the special all-wheel drive. The Mercedes-AMG is the only one here that is steered only via the front wheels, but this does not result in any real disadvantage in terms of high-speed stability and agility.

Audi RS 6 Avant, BMW Alpina B5 Touring, Mercedes-AMG E 63 S T, Exterieur

The loading sill of the E 63 S T is 585 millimeters high, making it the lowest in the comparison – which has to be said. Finally, the Mercedes-AMG also delivers the best driving dynamics values.

No steering resolves the road into the palms of the hand as high as that of the E, and none is so perfectly calibrated to the optimum hand torque. The result of the chassis remix: No Swabian housewife can scrape spaetzle from a board into boiling water as brilliantly dynamic as Mister T can be chased through curves and even over a racetrack – and they can do it at crazy speed.

Sure, the basic layout practically always allows you to let the rear off the leash, but the front wheels always bite. Once you learn to control the four-liter V8 engine, which is charged to 1.5 bar and has cylinder deactivation, you can easily keep the car in line. Whether on a country road or a race track, the fun band plays the same chingderassabum everywhere. After work, Hockenheim can feel like the slopes of the Remstal.

Aileron control

Okay, the sound of the V8 with twin scroll chargers and particulate filter no longer achieves the brashness of earlier days, but it retains passionate volcanism without the neighbors running after you armed with pitchforks after the morning cold start. They couldn’t really follow even by car, no matter which one. Unless, of course, you’re completely given over to the urge to play and have activated the drift mode in a complex ceremony while still in the garage.

Mercedes-AMG E 63 S T, Exterieur

Mercedes-AMG E 63 S T: Driving dynamics from unflinchingly fast to unabashedly transverse. Plus – the largest load space.

Then the maximum torque of 850 Nm only rushes to the rear axle, but thanks to the fierce maximum steering angle, equally fierce drift angles result, with which the rear end says goodbye in the direction of Panama. This works with all friction coefficients, no matter how high they are. No one needs it, but it fits perfectly into the E 63 S’s puzzle of characteristics. It has the most exciting character, delivers the best handling values with maximum driving pleasure.

The BMW Alpina achieves this with similar consistency, but with a different focus. With the Audi, on the other hand, the relationship between effort, result and cost is out of balance, but the approach is right. Perhaps there will be a more pointed plus version at some point? It wouldn’t be the first time. How does the literally great Frank Spilker and his stars sing again? Of all thoughts I appreciate the most – the interesting ones.

Conclusion

1st BMW Alpina B5 Biturbo Touring
461 points

More restraint in this segment? Hardly possible. The B5 profiles itself in this trio as efficient, longitudinally dynamic, comfortable and affordable. Agile? Somewhat less so.

2nd Mercedes-AMG E 63 S T
458 points

More touring cars in this segment? Hardly possible. Crazy and natural driving dynamics, brute drive that occasionally gets choked up. Plenty of space to boot.

3rd Audi RS6 Avant
456 points

More technology in this segment? Hardly possible. It helps to achieve the best handling of all RS6 times, but fails to deliver outstanding performance. Victory in features because of the assistance.

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