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How Does an Intercooler Work

In this article, we’re examining the intercooler.

  • What is an intercooler?
  • How does is it work?
  • What is its purpose?

Did you know that there are two type of intercoolers? Read on below to find out more!

What is an Intercooler?

An intercooler is an intake air cooling device used commonly on turbocharged and supercharged engines.

What is its Purpose?

The intercooler cools the air compressed by the turbo/supercharger. Thus, reducing the temperature and increasing the density of the air supplied to the engine.

How does it work?

When the air is compressed by a turbo/supercharger it gets very hot, very quickly. Therefore, its temperature climbs and its oxygen content (density) drops. When the air is cool, an intercooler provides a denser, more oxygen-rich air to the engine. Thus improving the combustion by allowing more fuel to be burned. 

It also increases reliability as it provides a more consistent temperature of air intake to the engine. This allows the air-fuel ratio of the engine to remain at a safe level.



Did you know that there are two type of Intercoolers?

There are two type of Intercoolers

1. Air-to-Air Intercooler

The Air-to-Air intercooler extracts heat from the compressed air by passing it through its network of tubes with cooling fins. As the compressed air is pushed through the intercooler, heat is transfered through the tubes and, into the cooling fins. Travelling at speed the cool air absorbs the heat from the cooling fins. Thus, this reduces the temperature of the compressed air.


  • Simplicity
  • Lower cost 
  • Less weight

This also makes it by far the most common form of intercooling.


  • Longer intake length due to having to get the intercooler to the front of the car
  • More variation in temperature than air to water.


The best placement for an air to air is at the front of the vehicle. The “front-mount” is considered to be the most effective placement.
When the engine layout or type of the vehicle do not permit the “front-mount” placement. The intercooler can be mounted on top of the engine, or even on its side. However, these are not considered as effective. This is because the airflow is not as effective. Thus, the intercooler can suffer from heat soak from the engine when the external airflow drops. These placements will often require additional air ducts or scoops to route the air directly into the intercooler.

2. Air-to-Water Intercooler

An Air-to-Water intercooler uses water as a heat transfer agent. In this setup cool water is pumped through the air/water intercooler, extracting heat from the compressed air as it passes through. The heated water is then pumped through another cooling circuit (usually a dedicated radiator). While the cooled compressed air is pushed into the engine.

These intercoolers (also known as heat exchangers) tend to be smaller than their Air-to-Air counterparts.


  • This makes them well suited to difficult installations where space, airflow and intake length are an issue. Water is more efficient at heat transfer than air. Thus, has more stability to be able to handle a wider range of temps.


  • However, this system requires the added complexity, weight and cost of a radiator, a pump, water, and transfer lines. Common applications for these are industrial machinery, marine and custom installs that don’t allow the easy fitment of an air to air, such as a rear-engined
  • vehicle.


The air to water can be mounted anywhere in the engine bay. As long as the radiator is mounted in a position with good airflow, and or with a Thermo, fan attached to it.

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