One of the reasons why turbocharged engines have more power than ordinary engines is that their ventilation is more efficient than the natural intake of a typical engine. When the air enters the turbocharger, its temperature will rise sharply and the density will decrease accordingly. The intercooler acts as a cooling air. The high temperature air is cooled by the intercooler and then enters the engine. If the intercooler is lacking and the pressurized high-temperature air directly enters the engine, the engine may be knocked or even damaged due to excessive air temperature.
Intercoolers are commonly found on vehicles with turbochargers. Because the intercooler is actually a turbocharged accessory, and its role is to improve the ventilation efficiency of the turbocharged engine.