Also, the electronic systems, extra hoses, solenoids and control systems add cost and complexity. Nonetheless, in recent times most automobile manufacturers use boost controllers on their turbocharged engines.{{citation needed}}
== Past and futureAlternatives ==
ThereIn arethe otherpast, outdatedboost methodspressures ofhave boostbeen control,controlled suchby asrestricting or bleeding off some intake restrictionair orbefore bleedit reaches the [[intake offmanifold]]. ForDesigns instance,which itrestrict isthe possibleintake toair installcan ause largea [[butterfly valve]] in the intake to restrict airflow as desired boost is approached. ItDesigns iswhich alsobleed possibleoff tothe actuallyintake releaseair large amounts of already compressed airfunctioned similar to a [[blowoff valve]], but on a constant basis to maintain the desired boost at the intake manifoldpressure. The currently popular exhaust gas bypass via wastegate is quite superior if compared to creating intake restriction or wasting energy by releasing air that has already been compressed. These methods are rarely used in modern system due to the large sacrifices in efficiency, heat, and reliability.
[[Variable geometry turbocharger]] can be used to manage boost levels, negating the need for an external boost controller. Also, the [[wastegate]] itself has a similar function to a boost controller, in that it is used to manage the turbocharger's boost pressure.
Other methods may come into widespread use in the future, such as [[variable geometry turbocharger]]s. With a sufficiently large turbine, no wastegate is necessary. Low speed response and faster spool up are then obtained using variable turbine technologies rather than a smaller turbine. These systems may replace or supplement typical wastegates as they develop. Control methods for the variable mechanical controls, such as the principles of closed loop will still apply even if they no longer involve [[pneumatics]].
