The W12 used by the flagship A8 is not the only twelve-cylinder Audi from the modern era as the original Q7 was offered for several years with a massive V12. Touted at its launch as the most powerful diesel engine ever installed in a passenger car, the twin-turbo 6.0-litre was a force to be reckoned with and used diesel know-how from the R10 TDI race car.

Also installed in the mid-engined R8 V12 TDI concept that never evolved to a production model, the diesel monster developed a mighty 493 bhp (368 kilowatts) and a mountain-moving 738 pound-feet (1,000 Newton-metres) of torque. To put those numbers in perspective, it had an extra 65 bhp and 74 lb-ft (100 Nm) over its spiritual successor, the SQ7 TDI. Today, we get to see the oil-burning luxobarge in an acceleration test all the way up to its top speed.

A dinosaur in today's automotive industry obsessed with downsizing, the Audi Q7 V12 TDI is still hugely capable. As a matter of fact, the Autobahn run shows the German luxury marque hitting 62 mph (100 km/h) in only 5.46 seconds or about a tenth of a second quicker than what Audi claimed back in 2008 when it launched the version.

This particular Audi Q7 V12 TDI had a little over 100,000 miles on the clock and it effortlessly hit 172 mph (277 km/h) per the vehicle's speedometer on an unrestricted section of the Autobahn. In reality, the vehicle was doing 163 mph (263 km/h) based on the data registered by the GPS-based onboard performance meter device, which is still slightly more than the electronically capped 155 mph (250 km/h) mentioned by Audi. Not too shabby for a vehicle that weighs a little over 2,600 kilograms (5,732 pounds).

It goes without saying there won't be another engine like this ever again, with Audi promising the current-generation A8 would be its last twelve-cylinder car. The entire VW Group is gradually discontinuing big engines, with the Touareg to be the last model from the VW core brand to use a V8. By the way, Wolfsburg's SUV also had a twelve-cylinder back in the day, a petrol W12 shared with the ill-fated Phaeton and the Bentley Continental GT.