GFB EX44 44mm V Band External WastegateThe EX44 features a 44mm valve and comes standard with 15psi springs installed (1 x 10psi outer and 1 x 5psi inner spring). By removing one or the other spring, you can achieve base boost pressures of 5psi, 10psi, or 15psi. Also available is a 7psi middle spring, which can be used in various combinations with the supplied spring to achieve base boost pressures of 5, 7, 10, 12, 15, 17, and 22psi*. When it comes to external wastegates, some things you