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U.K.-market Audi BiTDI engine adds extra turbo, oddly placed speaker

Audi's new diesel engine doubles up on the turbochargers, but its oddest feature is in the exhaust system.

Audi BiTDI 3.0 V-6
Audi's new TDI engine doubles up on turbos, but its oddest feature is in the exhaust system. Audi UK

Pop quiz, tough guy: How do you make VW/Audi's direct-injected, turbodiesel engines better? If you answered "add another turbo," then congratulations. You're now ready to work for Audi's R&D department!

Okay, so I'm sure that Audi's engineers are a bit more qualified than that, but "adding another turbo" is exactly what they did with the advent of the new BiTDI 3.0 V-6 engine. The new engine, which will find its way under the hood of diesel-powered A6 and A7 Sportback models in the U.K. market, features a two-stage turbocharger group that spins its flywheel to the tune of 309 horsepower and 479 pound-feet of torque (converted from the quoted figures in PS and Nm, respectively).

Speaking of tunes, Audi has taken a novel approach to tuning the exhaust note of the BiTDI 3.0 V-6 by integrating a "sound actuator" into the exhaust system. Essentially a speaker, the sound actuator "imposes a defined oscillation pattern on the exhaust flow and transforms the typical TDI exhaust note into a more sonorous roar that is closer to the output of a high-performance petrol engine." Nope, we don't get it either, but we do know what it sounds like:

Wonky exhaust system aside, the BiTDI engine delivers pretty good efficiency to go along with its torquey performance. With the help of eight-speed tiptronic gearbox, Audi estimates the new engine will motivate the A6 and A7 models while sipping diesel fuel at an optimal rate of 44.1 mpg on the U.K. test cycle (about 36.7 converted U.S. miles per gallon). Not bad for a largish AWD sedan/wagon.

The new BiTDI A6 and A7 Sportback models will be available for order from U.K. dealerships this month. No word on whether these engines will see North American distribution.