Cars stuff

Intercooler

06.18.2008 | 6:34 am | Car Accessories, Car Modifications

An intercooler (commonly known as charge air cooler) is a heat exchange device used to increase the intake air charge density of supercharged or turbocharged engines. The intercooler can be air-to-air or air-to-liquid. Intercoolers increase the output of the engine by decreasing the air intake temperature. This decrease in temperature provides denser intake charge for the engine and allows a bigger quantity of air and fuel mixture to be combusted on every engine cycle. Intercoolers come in various sizes, shapes, and designs, depending on the supercharger system they are attached to.

The system also has to meet the space requirements in order to successfully fit on an engine. Regarding the spatial design, the most common intercoolers are the front mounted intercoolers (also called FMIC), top mounted intercoolers (also called TMIC), and hybrid mount intercoolers (also called HMIC). All of these types of intercoolers can be cooled using an air-to-air system, air-to-liquid system, or even a combination of both.

Why should you need an intercooler? If you plan to mount a supercharger or turbocharger to your car, the intercooler is an important part of the system. The supercharger and the turbocharger are designed to push more air into the engine’s intake manifold and into the combustion chamber. Because of this, the air is heated, thus decreasing the performance of the supercharger (or even damage the cylinders or the engine). The intercooler compensates for this heat by cooling the intake charge. When air passes through an intercooler, it is cooled and its pressure is reduced. This increases the density of the intake air mass. By spraying fluid on the intercooler’s surface or on the air itself, you can achieve an even better cooling.

Where should you place your intercooler? The intercooler that exchanges heat directly with the atmosphere should be placed in areas with maximum air flow. These systems are usually placed in front, and called front mounted intercoolers (FMIC). Nissan Skyline and Mitsubishi Lancer Evolution both use this type of intercoolers. Many of the old turbocharged cars, such as Toyota Supra and Nissan 300ZX Twin Turbo have side-mounted intercooler systems (SMIC). The SMICs are smaller because of the space constraints. In some cases, to reach the capacity of a bigger intercooler, two side-mounted intercoolers have to be mounted. The top mounted intercoolers (TMIC) can be found on Subaru Impreza WRX or MINI Cooper S. In this case, the airflow is ensured by a hood scoop.

Which is better? Every intercooler has its cons. The TMICs are installed very close to the engine and can suffer from heat diffusion, which will reduce their efficiency. The FMICs require an open bumper design for maximum performance and are vulnerable to debris. The SMICs are small because of the space constraints.

The intercooler is very useful in controlling the temperatures of a turbocharged engine. Turbocharged engines have a great power output and this leads to higher combustion and temperature. To make an idea about the temperatures, exhaust gases passing through the turbocharger are around 450 degree Celsius (or 840 deg. Fahrenheit) and can get as high as 650 degree Celsius (or 1200 deg. F). If these temperatures are added to the ones in the cylinder, the whole engine is in great danger. By using an intercooler, the air from the induction system is cooled, resulting in higher performance without damage. The air-to-liquid intercoolers work exactly as the air-to-air ones, the only difference being the fact that they reject intake charge heat to an intermediate fluid. This fluid is usually water, which rejects the heat into the air through some kind of a radiator. Air-to-water intercoolers are heavier due to some additional parts (water pump, radiator, fluid). However, this intercooler uses lower overall pipe and intercooler length. This provides a faster response and gives the peak boost faster than regular air-to-air intercoolers.

If you want to tune your car with a turbocharger or a supercharger, the intercooler is a must. Not using intercoolers can lead to engine failure due to high temperatures. Also, the intercoolers will increase the performance of your turbocharger/supercharger by cooling the intake air mass.