Under their very different exteriors, the Audi RS6 Avant and RS Q8 are very similar machines. Both have the same 4.0 liter twin-turbocharged V8 with 591 horsepower and 590 lb-ft of torque. Those engines are mated to the same eight-speed ZF automatic and send power to extremely similar Quattro all-wheel drive systems. Both cars have similar suspension setups and both sport rear-wheel steering. The biggest difference between the two cars is weight. So which is actually the fastest?
In this new drag race video, we get to see the Audi RS6 Avant take on its heftier sibling, the Audi RS Q8. The Audi RS6 has a decent weight advantage but the RS Q8 has a tire advantage, as its rubber is wider. Plus, in this drag race, the track is soaked in rain. So the RS Q8’s weight and wider tires might actually help it find traction off the line.
Which is exactly what happens. The Audi RS Q8 gets a quick lead and since both cars are equally powerful, the RS6 does struggle a bit to catch up. However, its lighter weight and better aerodynamics do allow the RS6 to eventually catch up and win the standard quarter-mile race.
After that race, both cars to a rolling race, mid-gear, with their transmissions set to manual mode. They both roll to a specific point and the gun it, to see which is faster without the benefit of a standard start. In the rolling race, the Audi RS6 Avant wins handily, as its much lighter weight gives it an advantage.
Overall, the Audi RS6 Avant is the faster car, which isn’t too surprising. It’s quite a bit lighter, more aerodynamic and uses the exact same engine. So while the RS Q8 is brutally fast by SUV standards, it can’t match up with its smaller, lighter, more athletic sibling.