BorgWarner Unveils R2S Turbocharging System with Two VTG Turbochargers, efficiency and reduces emissions for clean engine concepts VTG turbocharger for low- and high, geometry (VTG) turbochargers delivers powerful boost, and facilitates rapid acceleration while significantly reducing emissions and fuel consumption. "Combining two of our latest VTG turbochargers, turbocharging technology consists of two electrically actuated VTG turbochargers arranged in series. A small high-pressure turbocharger provides most of the boost at low engine speeds. As engine speed increases.