page_title: Intercooler
section_title: In supercharged engines
hierarchical_section_title: Intercooler / Internal combustion engines / In supercharged engines
caption_attribution_description: The engine bay of a 2003 BMW MINI Cooper'S with the intercooler circled in red.
context_page_description: An intercooler is a mechanical device used to cool a gas after compression. Compressing a gas increases its internal energy which in turn raises its temperature and reduces its density. An intercooler typically takes the form of a heat exchanger that removes waste heat in a gas compressor. Intercoolers have a variety of applications, and can be found in air compressors, air conditioners, refrigeration, and gas turbines, and automotive engines, for example. They are widely known as an air-to-air or air-to-liquid cooler for forced induction internal combustion engines, used to improve volumetric efficiency. This is accomplished by increasing intake air density through nearly constant pressure cooling.
  Automotive intercoolers were first introduced in 1977 on the Porsche 911.
context_section_description: Turbochargers and superchargers are engineered to force more air mass (and thus more oxygen molecules) into an engine's intake manifold and combustion chamber. Intercooling is a method used to compensate for heating caused by supercharging, a natural byproduct of the semi-adiabatic compression process. Increased air pressure can result in an excessively hot intake charge, significantly reducing the performance gains of supercharging due to decreased density. Increased intake charge temperature can also increase the cylinder combustion temperature, causing detonation, excessive wear, or heat damage to an engine block or pistons.
  Passing a compressed and heated intake charge through an intercooler reduces its temperature (due to heat rejection) and pressure (due to flow restriction of fins). If the device is properly engineered, the relative decrease in temperature is greater than the relative loss in pressure, resulting in a net increase in density. This increases system performance by recovering some losses of the inefficient compression process by rejecting heat to the atmosphere. Additional cooling can be provided by externally spraying a fine mist onto the intercooler surface, or even into the intake air itself, to further reduce intake charge temperature through evaporative cooling.
  Intercoolers that exchange their heat directly with the atmosphere are designed to be mounted in areas of an automobile with maximum air flow. These types are mainly mounted in front mounted systems (FMIC). Cars such as the Nissan Skyline, Saab, Volvo 200 Series Turbo, Volvo 700 Series (and 900 series) turbo, Dodge SRT-4, 1st gen Mazda MX-6, Mitsubishi Lancer Evolution and Chevrolet Cobalt SS all use front mounted intercooler(s) mounted near the front bumper, in line with the car's radiator.
  Many other turbo-charged cars, particularly where the aesthetics of the car are not to be compromised by top mount scoops, such as the Toyota Supra (JZA80 only), Nissan 300ZX Twin Turbo, Nissan Silvia (S13/14/14a/15), Nissan 180sx, Mitsubishi 3000gt, Saab 900, Volkswagen, Fiat Turbo diesels, Audi TT, and Turbo Mitsubishi Eclipse use side-mounted air-to-air intercoolers (SMIC), which are mounted in the front corner of the bumper or in front of one of the wheels. Side-mounted intercoolers are generally smaller, mainly due to space constraints, and sometimes two are used to gain the performance of a larger, single intercooler. Cars such as the Subaru Impreza WRX, MINI Cooper S, Toyota Celica GT-Four, Nissan Pulsar GTI-R, Acura RDX, Mazdaspeed3, Mazdaspeed6, and the PSA Peugeot Citroën turbo diesels, use air-to-air top mounted intercoolers (TMIC) located on top of the engine. Air is directed through the intercooler through the use of a hood scoop. In the case of the PSA cars, the air flows through the grille above the front bumper, then through under-hood ducting. Top mounted intercoolers sometimes suffer from heat diffusion due to proximity with the engine, warming them and reducing their overall efficiency. Some World Rally Championship cars use a reverse-induction system design whereby air is forced through ducts in the front bumper to a horizontally mounted intercooler.
  Because FMIC systems require open bumper design for optimal performance, the entire system is vulnerable to debris. Some engineers choose other mount locations due to this reliability concern. FMICs can be located in front of or behind the radiator, depending on the heat dissipation needs of the engine.
  As well as allowing a greater mass of air to be admitted to an engine, intercoolers have a key role in controlling the internal temperatures in a turbocharged engine. When fitted with a turbo (as with any form of supercharging), the engine's specific power is increased, leading to higher combustion and exhaust temperatures. The exhaust gases passing through the turbine section of the turbocharger are usually around 450 °C (840 °F), but can be as high as 1000 °C (1830 °F) under extreme conditions. This heat passes through the turbocharger unit and contributes to the heating of the air be
caption: The engine bay of a 2003 MINI Cooper S. The top-mounted intercooler is circled in red.
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