Design of the 690 and 420 Touring Car Racing Engines

The paper presents design data and indicated, brake and mean effective pressure results for two successful racing engines developed by FIAT Auto Corse for touring car applications, namely the 690 2.5 liters V6 engine powering the Alfa Romeo 155 car developed for the 1996 International Touring Car (ITC) Championship and the 420 2.0 liters in-line 4 engine powering the Alfa Romeo 156 car developed for the 1998 Campionato Italiano Superturismo. In their first year of life, the sophisticated 690 engine was delivering 500 HP with a revolution limiter of 12000 rpm, while the more conservative 420 engine was delivering 310 HP with a revolution limiter of 8500 rpm. Brake mean effective pressures of these naturally aspirated engines were very close to the maximum achievable values for the racing engine technology of the late nineties, and certainly still a good reference point for development of new racing engines. Geometrical and operating parameters of these engines are provided in detail, as well as similarity rules for derivation of new engines.