Editing Forced induction (section)

=== High altitude uses ===
A reduced density of intake air is caused by the loss of atmospheric density seen with elevated altitudes. Therefore, an early use of forced induction was in aircraft engines. At {{convert|18000|ft|m}}, the air is at half the pressure of sea level, which means that an engine without forced induction would produce less than half the power at this altitude.<ref name="knuteson">{{cite journal |title=Boosting Your Knowledge of Turbocharging |last=Knuteson |first=Randy |issue=July 1999 |journal= Aircraft Maintenance Technology |access-date=18 April 2012 |url=http://www.kellyaerospace.com/articles/Turbocharging.pdf |archive-url=https://web.archive.org/web/20120617094358/http://www.kellyaerospace.com/articles/Turbocharging.pdf |archive-date=17 June 2012 |url-status=dead }}</ref> Forced induction is used to artificially increase the density of the intake air, in order to reduce the loss of power at higher altitudes.

Systems that use a turbocharger to maintain an engine's sea-level power output are called "turbo-normalized" systems. Generally, a turbo-normalized system attempts to maintain a manifold pressure of {{cvt|29.5|inHg|kPa}}.<ref name="knuteson" />