Note - Modfying this stuff is not suggested. It's located in 'BeamNG.Drive/content/vehicles/common/sounds Replace the .ogg with an 'empty/muted' sound.
thanks, but i also found the method i used before. i modified line 244 in the \lua\vehicle\turbocharger.lua file from "bovSoundVolumeCoef = min(max(turbo.bovSoundVolumeCoef or 5, 0), 1)" to "bovSoundVolumeCoef = 0"