We’re going to skip the joke – because this isn’t one – and get straight to the punchline: If the forthcoming 2014 Mercedes-Benz S-Class looks like it will lead the segment in interiors, the 3.0-liter turbodiesel in the 2014 Audi A8 L TDI takes the head of the table when it comes to engines.
After joining Audi for the 12 Hours of Sebring, we stood in the parking lot of The Inn On The Lakes on Sunday morning, our thousand-yard stare interrupted by the Citgo gas station across the street. We had one key, three bags, one white A8 L TDI, something like 17 gallons of diesel in the tank and one week to burn through it. For the purposes of a Quick Spin, we could have simply traipsed around the central Florida outback, all citrus, dusty scrubland and diners lifted from Cronenberg films, made short work of measuring the refinement and potential rarefaction of the oil burner under the hood and made our way back to the Orlando airport.
But dear readers, where would the adventure be in that?
After all, the wherefore of a diesel engine in a large luxury sedan we take to be only ostensibly about the CAFE numbers. Yet we think a side effect is that it demonstrates to US audiences what European businessmen and bureaucrats already know: Put a frugal diesel in a large car and you get the ant’s pants and the bee’s knees: room to move with interior space and room to roam with decent gas mileage.
So this A8 L TDI was our Bactrian beast, the camel we were going to ride until it ran out of fuel, at which time we’d fill it up and continue on. Our final route ran: Sebring, Miami, Ocala, Daytona Beach, New Brunswick (Georgia), Atlanta, Birmingham (Alabama), Atlanta. It was 1,682 miles of driving in ten days, it was two fill-ups, a lot of strange food, Spring Breakers, graffiti, Dairy Queen, sand and motorcycles – and one Ferrari – along the way.
But first we’ll give you the short story via our Driving Notes:
- The cipher to translate the diesel A8, thrown up in the sky like the bat signal, was “24-36-28-857.” The first three numbers are the EPA fuel economy ratings for the sedan – 24 city, 36 highway, 28 combined. Take that highway number and multiply it by the 23.8-gallon tank and you get a hypothetical range of 856.8 miles, enough to drive almost the entire coast of California – on the scenic route – from San Diego to the heart of the Redwood National Park near the Oregon border. Or you could go from New York City to Atlanta with ten miles worth of hydrocarbons left in the tank. That’s what you call “range.”
- The instrument striking the note is a 3.0-liter diesel V6 with a single turbo helping it put out 240 horsepower and 406 pound-feet of torque. That power number could read a little low for a long-wheelbase sedan with a curb weight of 4,564 pounds, but that lopsided torque figure is ready to pull the hard load. In price, weight and torque, it slots in between the long-wheelbase A8s with their 3.0-liter V6 ($79,395, 4,409 pounds, 333 hp, 325 lb-ft) and 4.0-liter V8 ($88,095, 4,630 pounds, 420 hp, 444 lb-ft) gasoline engines, but has 97 less horsepower than the 3.0-liter and is slower than both in the run from 0-60. It gets there in 6.4 seconds, the gas V6 takes 5.5 seconds, the V8 takes 4.7. On the other hand, it’s 0.6 seconds quicker than the Mercedes-Benz S350 BlueTec in the same race.
- Don’t be duped by the numbers, though – this car is appealingly brisk. All of the torque is called into service from 1,750 rpm, so even though it isn’t a firebolt, when giving it the heave at a light or when you need to jump into a (sizable) space in traffic, you never have to worry about having enough acceleration. Give it a running start and it’s even sweeter, the sedan being quick to pick up speed when rolling at 45-mph-and-above expressway clips.
- We also enjoyed the way it managed its power. One evening during the race weekend we drove the 4.0 TFSI some 8.9 miles from the track back to the hotel, and it was the celebrated jumping frog of Highlands County – push a couple of millimeters too far into the throttle travel, the turbos kicked in and you were off. It didn’t take long for us to keep our right foot resting as lightly as cotton candy on the accelerator, happy to avoid its “Catapult” mapping. The 4.0 TFSI is a fine car, but in just nine miles, we were ready to exchange the keys for the breezy-yet-brisk diesel.
- As for detecting it was a diesel by its noise, you’d have to stand outside the car, be quiet and listen closely, or sit inside the car, turn everything else off, roll the windows down, be very quiet and listen very closely. It’s a non-factor.
- The fuel mileage is a factor, and it’s why we loved this engine. Look, if we need to start clubbing other drivers over the heads with our V8- and V12-powered nether regions, there is the much more expensive W12 on offer or bottle rocket barges from the voiture couture houses of AMG and Alpina. But the A8 L TDI has everything we’re looking for in performance, and after 1,682 miles of city and highway driving at an average speed of 41 mph, we averaged 30.2 mpg. Compare that, in real-world driving, to the EPA’s highway mileage ratings for what could be called the competition: 31 mpg for the Mercedes-Benz S350 BlueTec, 25 mpg for the S400 Hybrid, 30 mpg for the BMW ActiveHybrid 7 and 23 mpg for the Lexus LS 600h L. Lest you think the hybrids are at a disadvantage, the S400 and Lexus are rated 19 mpg in the city, the BMW is rated 22 in the city – 5 mpg and 2 mpg down, respectively, on the A8’s city spec.
- The bonus: It has the largest gas tank, the furthest range and it’s the least expensive of them all. You’d save about $2,000 compared to the ActiveHybrid 7, almost $10,000 versus the S400 Hybrid, more than $10,000 versus the S350 BlueTec and more than the price of a brand-new A4 compared to the Lexus. And inside, it’s still all Audi A8 – so if you like the sedan with any other engine, you’ll like this one, too. Worlds have collided in this car, and they’ve gone champagne frugal supernova.
If you’d like the long story of our eight days and 1,700 miles in the southeast, and meeting the terrible roads in Miami and The Jedi at Champion Motorsports, then read on…