A turbocharger is an upgrade for internal combustion engines that uses forced, super-cooled air to create more power. An engine upgraded with a turbocharger is no longer normally aspirated. A normally aspirated engine relies upon vacuum to draw in air to cool the engine. According to Bauer's Automotive Handbook, both turbocharged engines and normally aspirated engines have their own drawbacks and benefits.
According to Jeff Hartman, author of "Turbocharging Performance Handbook," initial cost is a primary difference between a turbocharged and a normally aspirated engine. Purchasing a turbocharger as an aftermarket upgrade inherently comes with a price. Similarly, engines outfitted with turbochargers at the factory typically cost more than normally aspirated engines.
A turbocharged engine requires maintenance more often than one that is normally aspirated. The extra pressure inside the engine caused by a turbocharger puts a higher strain on the engine's components. Normally aspirated engines do not suffer this increased component wear.
According to Corky Bell, author of "Maximum Boost," turbochargers increase an engine's power, in turn increasing its top speed. However, until the engine has reached high enough RPMs, the vehicle is slower than it would be with a normally aspirated engine.
