Replace the leaky, slow responding plastic OEM Blow off valve (BOV) wirh the quicker responding more reliable valve from Perrin. This valve features adjustable spring tension when the valve vents. A looser setting will make it act smooth and more like stock. Harder setting will cause it vent later and with increased boost levels. You can also adjust flow control independently to help maintain the perfect amount of boost. not sure where to set it? no problem each valve comes out of the box, set up to work perfectly, for most setups.