Mercedes-Benz W 25 record car, 1934
In 1934 the debut of the new supercharged-engine MB racing car, built according to the 750 kg formula by the two designers Nibel and Wagner, marked the beginning of the most successful racing epoch yet in the history of the Daimler-Benz company. The car, well-known under its factory designation W 25 – later called "silver arrow" – started its successful career by winning the first race in which it was entered, which was held on the Nürburgring.
In the same year, Mercedes-Benz sent the W 25 on a record hunt in Gyon near Budapest and on the Avus. The record car was equipped with the M 25 B engine (bore/stroke 82/94.5 mm, displacement 3980 cc, 430 hp at 5800/min), the body was modified for the each event. In both record attempts, the usually quite prominent grille opening was significantly reduced for improved aerodynamic drag in combination with a lower need for cooling air.
There were two versions of the bonnet: In Gyon, it had neither air intake nor outlet, only two crescent-shaped apertures on each side were fitted at the end of the bonnet. On the Avus, a bonnet with a lower roof line and a wider middle pane was used, and it possessed air intakes and outlets.
With the W 25 record car, Rudolf Caracciola drove an international Class C (displacement of three to five litres) record over a distance of five kilometres with 311.98 km/h on the Avus on 10 February. At the end of October in Gyon, he set international Class C records with 317.5 and 316.6 km/h over a distance of one kilometre and one mile with a flying start as well as a world record with 188.6 km/h over a distance of one mile with a standing start.
Caracciola dubbed these cars “racing limousines”, a designation which was adopted by the press office and immediately became common.