Boost controller
A boost controller is a device in a turbocharged or supercharged car that regulates boost pressure. They can be as simple as a manual boost controller which one can easily fabricate oneself, or an electronic boost controller such as those made by Apexi. Increased boost pressure produces more power from the engine, and to prevent damage, one must install a boost gauge to monitor boost pressure while driving. Some factory turbocharged cars have a switch to regulate boost pressure, such as a setting designed for gas economy and a setting for performance. Because a boost controller will affect the air/fuel ratio to the engine, it is beneficial to have an air/fuel gauge or an exhaust temperature gauge inside the car in addition to a boost gauge. Due to the nature of an air/fuel gauge, (which is a voltmeter that usually takes a reading from the O2 sensor) the different readings are not always accurate, but it will provide an indication of if the mixture is running lean or rich. However, an exhaust gauge temperature can provide a more accurate indication of the air/fuel ratio. Generally a manual boost controller will not be accessible from inside the car, though some are designed to be. The installation inside the car will be sligthly different from in the engine, as the tubing must be longer and a hole must e drilled. It is possible and beneficial to use two manual boost controllers at different settings Electronic boost controllers, such as the Apexi AVC, are mounted inside the car, as it is necessary for the driver to see the screen and access the controls.