The first pilot studies for the new Audi 100, internally named C4, go back to the time when the preceding model was introduced to the public by Audi. The thought of combining the highest possible function with the fascination of a new relish for driving proved to be a real challenge for the development team. The guidelines were: the new Audi 100 was to remain compact, to echo the shape’s groundbreaking aerodynamics and to express the Audi philosophy with an aesthetic design dynamic.
There were five clay models with slight modifications up for discussion by the company management at the start of 1986. Each had its own appeal. Yet after a hard selection process only one made the grade: the new Audi 100.
The design had succeeded. It was clear at first sight: The typical Audi front clip signaled dynamism, the clear contours emanated poised elegance. The side windows were placed almost straight to reduce sunlight and keep the interior cool. At the same time they prevented water dripping onto the seats when it rained as in its ecessor. Nevertheless the drag coefficient was at 0.29 once again in the top end of aerodynamic cars.
Keeping the front drive and quattro drive in the Audi 100 new edition was a matter of course for the technicians but then again also fully exploiting the existing optimisation potential. The starting point of the improvement measures was the recognition that the car body rigidity had a significant influence on the chassis construction and the vibration behaviour. The C4 had 30 per cent more torsional rigidity than its predecessor. Cementing the roof with the roof frame for the first time was jointly responsible for this.
The fourth generation Audi 100 with three different engine concepts was offered from the start. On the one hand the further development of the 2 litre four cylinder or relatively 2.3 five cylinder engine, on the other hand the completely newly designed V6 engine. The first engine construction stage still had a 2,393 cm³ capacity and a 113 kW (153 PS) performance when first trialed for test purposes in 1986. The capacity was increased to 2.8 litres, the con-rod lengthened and the engine block was raised as after-effects from this. The new power plant together with a multipoint injection system and the contactless ignition performed at 128 kW (174 PS). An essential feature of the V6 engine however was a performance and torque enhancing controlled intake manifold. The engine owed its special torque characteristic to these constructional elements. There was an intake manifold with variable lengths and variable diameters for every cylinder. A long runner for a high torque and a short runner for high performance. The change from long to short runners took place via a controllable flap. All the flaps remain closed for a high torque up to 4,000 rpm. The intake air has to take the long way. The flaps open fully from 4,000 rpm. The air could take the short way for more performance. A small detail with a great effect: the torque increase was almost 10 per cent between 2,000 and 3,500 rpm.
The Audi 100 model series was renamed to Audi A6 in 1994. A comprehensive facelift changed many details; the car body basic design and the former Audi 100 technical basis remained untouched. The only five cylinder petrol engine left in the offering was the four valve turbocharged engine in the Audi A6 performing at 169 kW / 230 PS.
New four and six cylinder five valve engines came into use from autumn 1995. The S6 4.2 engine performance increased to 213 kW/ 290 PS. Quattro GmbH put the model series S6 plus and S6 plus Avant with 240 kW/ 326 PS on the market as the series top models in June 1996.
From now on whether Audi 100 or A6, the C4 was one of the most innovative and technically interesting models in the 100 model series. A total of 711829 models were built from 1990 to 1997.