In South Africa, we have tough ambient temperature conditions and this places extra strain on turbocharged vehicles. The most common areas affected on turbocharged vehicles are turbos, cylinder heads, and pistons. Many people believe that turbos fail because of a lack of lubrication and bearing failure, which will result in damage to the turbo driveshaft. Although this can happen, it is only the case in the minority of turbo failures. The main reason for turbo failures is excessive exhaust gas temperatures. Average EGT’s under full load should vary between 650°C – 800°C for modern turbo diesel vehicles and 700°C – 900°C for modern turbo petrol vehicles. Temperatures exceeding 900°C may cause turbo failure.

Excessive EGT’s will cause fatigue to the turbo material and will create heat cracks and eventually result in component failures. Intercooling will cool down the charge air and will result in cooler EGT’s. In other words, intercooling is one of the best ways to prevent turbo failures. An intercooler will definitely help keep all engine components at a stable temperature. Cylinder head and piston failures will also be the result of excessive heat causing fatigue to these components. As for turbo’s, intercooling will result in lower operating temperatures for both cylinder heads and pistons.

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

What does an intercooler do?

An Intercooler cools the air compressed by the turbo/supercharger reducing the temperature whilst increasing the density of the air supplied to the engine.

How does an intercooler work?

As the air is compressed by a turbo/supercharger it gets very hot, very quickly. As its temperature climbs its oxygen content (density) drops, so by cooling the air, 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 intake air to the engine which allows the air-fuel ratio of the engine to remain at a safe level.

There are two types of intercoolers; Air-to-Air and Air-to-Water. An 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 it transfers the heat to the tubes and, in turn to the cooling fins. The cool air from outside, traveling at speed, absorbs the heat from the cooling fins reducing the temperature of the compressed air. These systems advantages are simplicity, lower cost and less weight. This also makes it by far the most common form of intercooling. The downsides can be a longer intake length due to having to get the intercooler to the front of the car and also more variation in temperature than air to water.

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 making them well suited to difficult installations where space, airflow, and intake length are an issue. Water is more efficient at heat transfer than air and has more stability so it can handle a wider range of temps, but 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 engine vehicle.

Intercooler Placement

The best placement for an air to air is in the 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, an intercooler can be mounted on top of the engine, or even on its side, but these are not considered as effective as the air flow is not as good and 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.

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

Since the year 2000, the number of turbocharged vehicles in South Africa is steadily increasing. And the growing trend continues. There are many reasons for this: Turbo engines are a convincing choice thanks to low fuel consumption, improved engine efficiency, optimised exhaust emissions and a reduction of the thermal load on the engine. In addition, power increases over the entire engine-speed range can be achieved by this means.

While all of this is really good news for the motorist there are some implications when there is a mechanical failure in the compressor side of the turbocharger. In the event of mechanical damage to the turbocharger, the intercooler should be replaced as well. It cools down the 150-degree-Celsius hot air compressed by the turbocharger before it reaches the combustion chamber of the engine. The cooling takes place via the ambient air (air flow) or the engine coolant.

In addition to the original parts we sell, we are in certain instances able to provide you with the choice of a quality, value for money alternative on some of the popular applications. Rest assured that we have thoroughly qualified these parts to ensure that they are able to perform at the required level. In the unfortunate event that you do need an intercooler replacement, contact Silverton Radiators today!


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