1.2 TDI "3L"
The Audi A2 1.2 TDI had the lowest drag coefficient of any car in the world at the time of its launch. It was also one of the most economical and least polluting, only emitting 81 g/km (German emission standard D4) to 86 g/km (D3 emission standard) CO2 emissions. The Audi A2 3L reuses the engine and special gearbox developed for the equally efficient Volkswagen Lupo 1.2 TDI 3L.
Two versions of the car were available in Germany during its production run. The D4 version, which used only 3 l/100 km (94 mpg; 78 mpg), was "standard." It had no power steering, climate control or other extras, with the only optional extra being body coloured door handles and wing mirrors. There were no optional extras because optional equipment adds weight and loses economy. It had a fixed rear seat cushion. The tested fuel economy was 2.88 l/100 km.
The second version, which was at least available in Germany, was a D3 version which was still capable of 3.0 l/100 km. This version had options for climate control, a winter pack, and a comfort pack, but was not available in all markets. Ordering these packs ensured power steeering or spot lamps as part of a package. The OSS system was not available at all on the 3L.
Both versions had thinner glass, lighter seats, and 14" Magnesium alloy wheels. The standard tyre fitment was 145/80 R14 T76 Bridgestone Ecopias or Continental Winter Tyres using very flat wheel covers to minimize turbulence. The engine block was also made from a light alloy, so even though it was a diesel, it weighed just 100 kg (220 lb).
The rear spoiler was reshaped, moved and extended through wind tunnel testing, and additional underbody panels were added to minimize drag to achieve a 0.25 cd figure. The car had an automated manual transmission with a Tiptronic mode on the selector. The car also had an ECO mode. When engaged it limited the power to 41 bhp (31 kW; 42 PS) (excluding kick down) and programmed the transmission to change up at the most economical point. ECO mode also activated the start/stop function, a feature that was new to European cars at the time. In ECO mode, the clutch was disengaged when the accelerator pedal was released for maximum economy, so the car freewheels as much as possible, with the clutch re-engaging as soon as the accelerator pedal or brake pedal is touched. The 3L also has only 4 wheel bolts and finned alloy brake drums at the rear, along with many aluminum suspension components. An internal presentation from Audi appears to indicate that the complete shell of a 3L A2 weighs around 15 kg (33 lb) less than that of a "normal" A2. The 3L has been noted on the Autobahn under non-scientific conditions to be faster at top speed than the standard A2, mainly as a result of the extremely long 5th gear ratio and the excellent aerodynamics.
A total of 6450 1.2 TDI models were built.
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