The COBB XLE BOV can operate in one of three modes with simple adjustments. Full recirculation is achieved by plumbing the primary output back into the intake pre-turbo with the auxiliary port closed. Full atmosphere is possible by opening both the primary port and auxiliary port to atmosphere. A hybrid mode is also possible by pluming the primary port into the intake and leaving the auxiliary port open to atmosphere, causing much of the air to recirculate to retain driveability, while still creating an audible exhaust of some of the boost pressure.
Spring preload determines the pressure differential across the BOV piston required before the BOV opens and releases the pressurized intake charge. The COBB XLE BOV can be adjusted by loosening the locknut and turning the hex-head shaft clockwise for more preload or counter-clockwise for less preload. Once preload is set, the locknut is retightened and ensures the adjustment is secure.
Materials used to construct the COBB XLE BOV ensure ease of maintenance and long service life. The mounting flange, body, vent cover and piston are constructed of 6061 T6 aluminum, the spring seat is made from 303 stainless steel and the primary outlet is polished cast aluminum. O rings are used around the piston and on the mounting flange to ensure optimal sealing. The valve body is hard anodized for strength and corrosion resistance. The piston is dry filmed lubricated, providing enduring maintenance free service.