GFB puts the key to boost control in YOUR hands! All turbocharged vehicles utilize some form of factory boost control, most of which display a tendency to be conservative in allowing the boost to build up, and then taper away noticeably toward redline (see diagram). A GFB Boost Controller however, not only allows quick and easy boost level adjustment, but it can also reduce the boost threshold (the RPM at which boost starts to rise) and maintain a rock-steady upper limit.