Turbo flutter, often written as stututu, is the chattering sound made when a turbocharged engine releases compressed air back through the turbo instead of through a blow-off valve, a characteristic prized in modified car culture. Clips of Fortuners and other turbo diesel SUVs producing the effect have circulated widely in short car videos, where the sound instantly identifies a tuned setup. Its appeal endures because it is short, recognisable and easy to drop over acceleration footage, making it a staple for automotive edits, memes and reels.