Narvey Vilaythong wrote on Wednesday, September 23, 2009 - 11:11 pm:Its a bad thing, it is put there so that your car would make a fullyhecticksickkiller sounds. It works by not letting air vent back into the system, just surging it back through the turbo compressor which make the turbo stall. Not a good thing, i say you should fit a stock or aftermarket plumb back BOV to your car. My two cents.