The second part of the efficiency drive through Austria and Switzerland, like the first, was thoroughly successful: 20 randomly selected readers of a motoring magazine and a team of two from Audi once again fully exploited the efficiency potential of the new Audi A4 2.0 TDI with an output of 88 kW (120 hp) in order to drive a route of 1,650 kilometers (1,025.26 miles) from Vienna to Basel and back on a single tank of fuel.

All eleven teams reached the finish on Sunday: the most efficient driver duo achieved an average fuel consumption of 3.32 liters of diesel fuel per 100 kilometers (70.85 US mpg). This equates to CO2 emissions of 88 grams per kilometer (141.62 g/mile). With these figures, it would even have been possible to cover a distance of over 2,000 kilometers (1242.74 miles).

This achievement once again topped the outstanding result of the first part of the efficiency drive from Basel to Vienna and back. The winning team of that round, which also lasted 1,650 kilometers (1,025.26 miles), had recorded an average fuel consumption of 3.44 liters per 100 kilometers (68.38 US mpg) and CO2 emissions of 91 grams per kilometer (146.45 g/mile). This, however, was at a higher average speed of 81.4 km/h (50.58 mph).

With full concentration from beginning to end and outstanding levels of enthusiasm, the participants in fact managed to surpass the very high expectations. After a total driving time of 22 hours on average with an average speed of between 73 and 80 km/h (45.36 and 49.71 mph), the white Audi A4 cars reached their destination. It thus became clear just what potential there is in the driver’s foot for reducing fuel consumption.

The new two-liter TDI engine provides ideal conditions for economical driving. With a combined consumption figure of just 5.1 liters per 100 kilometers (46.12 US mpg) and CO2 emissions of only 134 grams per kilometer (215.65 g/mile), the efficiency of the sportiest midsize sedan is simply outstanding. At the same time, the A4 is always capable of bringing the impressive dynamism that distinguishes every Audi onto the road.

However, participants in the Audi efficiency competition significantly bettered even these impressive combined consumption figures. The winning team needed just 3.32 liters of diesel fuel per 100 kilometers (70.85 US mpg). This equates to CO2 emissions of only 88 grams per kilometer (141.62 g/mile) – an outstanding figure at an average speed of 74.6 km/h (46.35 mph). Five teams achieved under 3.45 liters (over 68.18 US mpg). But even the Audi in eleventh place recorded an impressive average fuel consumption of 3.50 liters (67.20 US mpg).

To achieve these extremely low figures, the teams had the air conditioning switched off nearly all the time. However, considering the amount of fuel left in the tanks of the eleven Audi A4 cars at the end, it would certainly have been possible to enjoy the comfort of the high-performance, ultra-efficient automatic air conditioning as well.