Someone smarter than me can chime in, but the bad surging/ flutter is under high load. It wears on the bearings.
There is probably always flutter (like a stustustu sound) on the stock system, but adding an intake, scoop and BPV or blowoff valve make it more noticeable so you can hear it while driving.
There is probably always flutter (like a stustustu sound) on the stock system, but adding an intake, scoop and BPV or blowoff valve make it more noticeable so you can hear it while driving.