You can watch this episode on Prime Video or read a summary on the Initial D Wiki . Initial D Fourth Stage Part 1
In the seventh episode of Initial D Fourth Stage , titled "The 85's Raging Turbo," Itsuki equips his AE85 with a turbocharger and Takumi later uses it to challenge arrogant Tokyo drivers in a Silvia S15, showcasing the difference between circuit racing and touge drifting.