Fast Audis aren’t a new creation, they’ve been around for many years, running with S and RS variants of Audi’s cars. What is new though, is high-speed diesel-powered Audi’s. Last year we drove Audi’s SQ5, their first diesel-powered S model. Now this sublime 3.0-litre Bi Turbo diesel engine has found a new home in the Audi A6, resulting in the fastest diesel saloon we’ve driven to date, and one that’s capable of dismissing a vast amount of petrol-derived alternatives too. You can’t question Audi’s expertise at producing potent diesels, having five diesel-powered wins under their belt, at the infamous 24hours of Le Mans endurance race.
The A6 Bi Turbo doesn’t wear an S badge, although after our week-long test the badge wouldn’t look out of place. Apart from the optional 20” rotor design alloy wheels (19” as standard) and the mammoth brake callipers, there’s little to hint at this A6’s sporting potential. This new A6 Bi Turbo is available across two trim specifications, SE and S Line, our test car was the top-spec S Line variant, complete with a host of additional equipment. As standard it’s well appointed with Audi drive select, Bluetooth interface, climate control, cruise control, 7” colour information system, S Line sports suspension, sports seats and Xenon lights all included. The principle options fitted to our A6 were the sports differential, led headlights, MMI navigation and 20” alloys.
This latest A6 offers elevated levels of comfort and refinement for all occupants, there’s a great sense of space inside, with a cavernous boot for your luggage too. As we have come to expect with Audi’s the fit and finish is exemplary, the MMI system is clear and intuitive to use. I particularly like the instrument cluster in Audi’s, they have large clear, easy to read dials with an uncluttered layout.
Around town the A6 Bi Turbo is docile and effortless thanks to its silky-smooth eight-speed automatic transmission. For the majority of our town drives we had the car in either comfort or auto mode within the Audi drive select programme. Once on the open road we selected dynamic mode which instantly alters the car’s behaviour. The car comes alive, with a healthy growl from the exhaust, the sound emitted is more akin to a V8 petrol than a V6 diesel, the throttle response is sharpened and the steering becomes noticeably heavier. Push the A6 through a twisty section of road and it feels poised, responsive and much smaller in size than it actually is. The sports differential aids cornering, with Audi’s Quattro all-wheel-drive system offering unparalleled levels of traction. It’s here where it scores well over its closest rival, the BMW 535d. The BMW does offer an extremely engaged driving experience, although we’ll have to put the two cars up against each other before choosing one over the other. The throttle in the A6, although responsive has a long travel and requires a good stretch to extract maximum acceleration. The mid-range torque is probably best described as mind-blowing, to put it into perspective, the A6 Bi Turbo has 100Nm more torque then the 4.0-litre V8 petrol-powered Audi S6.
For the first time I would strongly consider purchasing a diesel-powered saloon over a petrol alternative, this A6 Bi Turbo ticks all the boxes, it’s comfortable, economical and blisteringly fast. It’s not exactly inexpensive to purchase, however it’ll cost you a lot less to run than a high-performance petrol car. It’s now clear to see why Audi went the diesel route for Le Mans.[table “111” not found /]