Tier One Honeywell has developed a variable geometry turbocharger for motorsport applications. The first application was the Le Mans-winning Audi R15 TDI LMP1 car.
Similar technology is widely used in passenger cars because it improves transient and steady-state performance and fuel consumption. It gave the Audi race team the same benefits but Honeywell worked together with Audi Sport for three years to ensure durability at 1000°C exhaust gas temperatures.
Honeywell’s chief engineer for turbo technology Craig Balis said: “Racing turbos are similar to commercial turbos in terms of materials used. To ensure they perform reliably in a high temperature environment our engineers worked closely with Audi, gaining better understanding of the new race engines’ duty cycles.”
Like many passenger car applications the race turbos use electric actuators to adjust the guide vanes, but transient response was improved further using ball instead of plain bearings.
The Audi engine is a 5.5-litre 90° V10 developing 440kW and over 1050Nm torque. Each cylinder bank is fed by one turbo. Maximum boost pressure is 2.59bar absolute.
Passenger car engines run exhaust gas temperatures of around 850°; the Audi V10 around 1000°C. Gasoline engines run up to 1050°: “The latest Audi win at Le Mans opens up variable turbine technology making an entry into gasoline-powered race series,” said Balis.
Honeywell supplies the turbos for the global race engine programme. There is speculation in motorsport that F1 and Indycar will return to boosted engines to improve the relationship between race and road technology.
Peugeot’s Le Mans diesel used two fixed geometry Honeywell turbos.