2015 Audi A8 L TDI: Real-World Fuel Economy
Big luxury cars are great. If you haven’t actually had the chance to drive one, go try that 5-year-old Mercedes-Benz S-Class in the dealership’s used-car section the next time you’re there to buy a new Camry. But big luxury cars often come with other big things — big weight, big engines and quite a thirst for fuel. This is starting to change, however, as more of these large luxury cars start to feature alternative-fuel powertrains like the long-wheelbase 2015 Audi A8 L TDI and its turbocharged diesel V-6 engine.
Related: Research the 2015 Audi A8
German automakers have been at the forefront of diesel technology in passenger cars with all of them offering some form of it, and the fuel economy gains are significant. A standard Audi A8 L with the supercharged 3.0-liter V-6 engine is rated at 19/29/22 mpg city/highway/combined. Not bad for such a big car. Move up to the turbocharged 4.0-liter V-8 and your mileage drops to 18/29/22 mpg, a nearly identical rating. Splurge for the slick W-12 engine and you’ll get only 14/22/17 mpg. But tick the diesel box and your big, comfy A8 L could return 24/36/28 mpg. The combined city/highway rating is 27 percent higher than that of the base engine.
Those are some impressive numbers for a vehicle this big and heavy, but are they realistic in real-world driving? We loaded an A8 L TDI with three people and some weekend luggage for a fall-color tour of southern Ontario earlier this year.
The 300-plus-mile route took us from Ann Arbor, Mich., through Detroit and over the Detroit River into Ontario, where a combination of highway and country roads kept the A8 at a reasonable speed. We stopped in various small towns and at roadside attractions to sample the end-of-season fish fry and a couple of the region’s wineries.
The A8 L is a remarkable touring machine, packed with technology and trimmed to an impressive level with wood, leather and faux suede. Front seat or rear seat, there isn’t a bad place to sit, especially with the Luxury Package that my $98,575 test car featured. The panoramic sunroof lets plenty of light shine onto the diamond-stitched Valcona leather interior, and the open-pore wood trim looks dynamite. There’s massive legroom for backseat passengers thanks to the extended wheelbase, and those backseats are heated, which was useful in chilly Ontario.
In my experience, diesels almost always get better than their EPA figures, and the A8 L TDI was no exception. During my 328.3-mile voyage, it consumed just 9.63 gallons of diesel fuel. That translates into a combined 34.1 mpg, which is considerably more than the EPA’s rating, and closer to the 36 mpg highway figure. That’s extraordinary for this big Audi, and even bests some compact so-called “economy” cars.
Cars.com photos by Aaron Bragman
