TDI technology was proven by VAG at Le Mans, and in the WTCC with the Audi R10 in 2006-2008 and the SEAT Leon TDI (2ltr) which ran from 2008-2011 in the WTCC and BTCC, so if thats a VAG car (Audi, SEAT and VW use this tech), the TDI tech comes directly from these Motorsport programmes, that VAG used, at great expense, to improve their diesel systems.
Those 2ltr TDI lumps have bag fulls of torque!
Its impossible to introduce road going relevance to F1. Sportscar and Touring Car racing is where the big car manufacturers go to develop new tech!