The 90hp TDi engines use a conventional Garrett GT15 turbocharger ( 90hp Vnt15 ) with an variable-geometry exhaust housing. These turbo's are designed for up to 15 psi sustained boost with peaks of 18psi. For higher boost levels, improved performance, and lower EGT's, PDR recommends the Garrett variable-geometry 110hp VNT15 and 150hp VNT17 turbochargers. These are factory Volkswagen turbochargers from the European 110HP and 150HP VW TDi diesel engines. These turbos upgrades are for the 90HP TDi engines and will not work for the 100HP PD diesel engines.

With the variable geometry turbo there is no waste gate. All of the engine exhaust passes through the turbine all the time. At low engine speeds a set of vanes inside the turbine housing move to direct the exhaust gases through the turbine at a shallow angle and higher speed. This causes the turbine to spool faster, reaching optimal boost levels sooner. As engine speed increases the vanes move toward a more open angle. This allows less energy to be transmitted to the turbine wheel so boost levels are controlled.

VNT15 turbo from the 110HP European engine is designed for sustained boost levels of 18psi and peaks of 20psi. This turbo is a good choice for milder engines upgrades. The VNT15 turbo offers a bolt-in replacement for the existing Garrett 90hp Vnt turbo.

VNT17 turbo from the 150HP European engine is designed for sustained boost levels of 22psi, and intended for any set-up that can push past a sustained 18psi. This turbo is the only choice for the more aggressive engine upgrades and those pushing the limits. The VNT17 turbo will require other modifications to complete the installation, due to the different position in which the turbo fits in engine compartment. The intake hose and/or exhaust housing may need to be changed to fit the turbo to the existing intake and exhaust systems.