Intercoolers are heat exchangers used with forced induction systems, like turbochargers and superchargers. Their
is to cool the compressed air before it's sent to the engine. This results in better engine performance.
What Does an Intercooler Do?
Intercoolers take the compressed air from a turbo or supercharger and extract the
heat to reduce the temperature. Forced
induction systems compress the air, which increases the temperature. As the temperature rises, the air density
An intercooler works with the supercharger or turbo to send cooler, denser, more oxygen-rich air to the engine. This
helps increase engine efficiency and prevent engine knock for better reliability.
Types of Intercoolers
There are two main types of intercoolers: air-to-air and air-to-water. Intercoolers are typically mounted in between
engine and the supercharger or turbo. Some intercoolers mount on the top or side of the engine. Placing an
in these locations isn’t as effective since they can suffer from heat soak. These setups need more air routing
to get the air into the intercooler.
Intercoolers have a core, piping, and end tanks. The intercooler design affects the cooling and airflow properties.
fins allow for better heat transfer, but a higher fin density can restrict airflow. The size is also important.
isn’t always better, as an intercooler that is too large can cause boost lag.
Air-to-air intercoolers usually mount in the front of the engine bay for easy access to the outside air. They're
common than air-to-water intercoolers as they’re cheaper, weigh less, and have a simpler design.
A drawback of air-to-air intercoolers is the longer intake length. Since they’re mounted in the front of the engine
more tubing is required to reach the engine. This can result in wider variations in temperature. They also rely on
air generated by the vehicle being in motion, so heat soak can be an issue when the car’s at a stop.
When it comes to the design of the core, there are two main options: tube-and-fin and bar-and-plate.
Tube-and-fin intercoolers use a network of tubes with cooling fins to reduce heat. They transfer heat as air passes
through the system, sending cooler and more dense air to the engine. They’re cheaper than bar-and-plate styles and
less of a pressure drop for better airflow. However, heat soak can be an issue and may cause overheating, which will
The tube-and-fin design is common on stock intercoolers. Performance intercoolers usually have a bar-and-plate style.
Bar-and-plate intercoolers are stronger and heavier than tube-and-fin intercoolers. They’re also more expensive but
provide greater heat transfer and cooling. The air passes through a series of plates and bars that act as a heat
They can handle more abuse compared to the tube-and-fin intercooler. Bar-and-plate intercoolers offer better
at a higher cost. They’re better in stop-and-go traffic as they can hold a cool charge better.
Air-to-water intercoolers are also known as air-to-liquid intercoolers or charge air coolers. They use water or
to transfer heat from the air as it passes through the system. Heat is extracted from the compressed air by the
that’s pumped through the intercooler. The cooled air goes to the engine while the heated water goes through another
cooling cycle. Typically through a separate radiator.
Also referred to as heat exchangers, air-to-water intercoolers are smaller than air-to-air intercoolers. This makes
great for smaller engine bays where space or intake length may be an issue. Compared to air, water is more efficient
can handle a large temperature range.
Air-to-water intercoolers are more complex, but also more effective. They’re heavier and cost more as they have
coolant and transfer lines, a pump, and a radiator. Where air-to-air intercoolers go in the front, air-to-water
have more options. They can be mounted in other places in the engine bay as long as the radiator can get proper
or has a thermo fan.
Intercoolers vs Radiators
Both intercoolers and radiators are different forms of heat exchangers. While almost every car has a radiator, not
have an intercooler. Intercoolers are only used in cars with a forced induction system. Radiators use fluid or
to transfer heat to the air to keep the engine cool. Not all intercoolers operate this way. So while they serve a
similar function, they’re not used in the same capacity.
Does a Turbo or Supercharger Need an Intercooler?
Intercoolers aren’t required with a forced induction system, but they are recommended. An intercooler won’t add any
horsepower, but the added engine efficiency can contribute to better performance. Some supercharger and turbocharger
kits even come with an intercooler included.
Sources: Intercoolers-How They Work, MotorTrend | How Does an Intercooler Work, Turbosmart | The Differences Between Air-to-Air and Air-to-Water Intercoolers, Engineering Explained
Image Credit: Creative Commons
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