Your HPFP is an integral part of the B9 3.0T & 2.9T platforms direct injection (DI) system and provides exceptionally high-pressure fuel (exceeding 2900psi) to the injectors. When running turbo upgrades or ethanol fuel, the stock HPFP internal volume becomes the limiting factor when increasing power. IE's HPFP internals install into your factory pump housing and increase the bore and piston size of the pump internals, adding more flow, delivering more fuel, and safely allowing for higher horsepower & torque output.