The development of Garrett^® VNT™ turbocharger started in 1990 when the TD2502 was first launched based on the old TB25 model. Controlled by a pressure actuator connected by hose directly to the compressor outlet, this was VNT™ technology in its simplest; the vanes were at the minimum flow position at engine start up and during low speed/low load running while at higher engine speeds and loads, the vanes opened up. This ensured that the acceleration of the turbine wheel and compressor wheel was maximized under low energy conditions to give rapid torque rise at low engine rpm and yet still allow high gas flow and reduced back pressure for maximum engine power.

The VNT™ principle was then applied to our GT range of turbos and the development has taken it from the original version (dubbed the generation 0) all the way to the current 3^rd generation enhanced by the latest optimization. The different VNT™ generations can be identified by their model numbers; starting with GT (1^st generation), GTA (2^nd generation), GTB (3^rd generation) and GTC (optimized 3^rd generation). Each one of these generations represents a significant improvement in the design, performance and durability of the VNT™ mechanism.

The advanced design of the latest 3^rd generation turbo allows us to optimize the material choice for each individual component to meet our OEM customers performance requirements. For the nozzle assembly, we are using 8 different materials, each one chosen specifically for the job that it has to perform. Some parts are also Gas Nitrided, which delivers improved surface hardness, wear resistance, fatigue life and corrosion resistance.