How can I adjust the turbo boost ?

Adjusting the boost is straightforward. However, it depends on the type of boost controller. For a standard Wastegates actuator, simply recalibrate the actuator to open (more or less) for a given pressure. Changing the length of the rod that attaches to the Wastegates lever accomplishes this adjustment. For mechanical boost control systems, adjustments may involve changing the setting on a regulator valve(s). For electronic boost control systems, adjustments may need to be made to the vehicle’s engine management system. For an external Wastegates, adjusting the boost often requires turning the adjustment screw (when equipped) to increase/decrease spring load, changing Wastegates springs, or shimming Wastegates springs.
IMPORTANT: WHILE ADJUSTING THE BOOST IS STRAIGHTFORWARD, OFTEN THIS CHANGE REQUIRES MODIFICATIONS TO THE ENGINE FUEL MANAGEMENT SYSTEM!