Selection method
For many car fans, the intercooler in the front bumper is a dream modification part in their hearts, and it is also an indispensable performance symbol, just like the sound of the pressure relief valve. However, what is the knowledge of various intercoolers that look the same on the outside? What matters should be paid attention to if you want to upgrade or install? The above questions will be answered one by one in this unit.
The purpose of installing an intercooler is mainly to reduce the intake temperature. Perhaps readers will ask: Why do we need to reduce the intake temperature? This requires mentioning the principle of turbocharging. The working principle of turbocharging is simply to use the exhaust gas of the engine to impact the exhaust blades, and then drive the intake blades on the other side to force the compressed air to be sent to the combustion chamber. Since the temperature of the exhaust gas is usually as high as 800 or 900 degrees, the turbine body is also in an extremely high temperature state, which will increase the temperature of the air flowing through the intake turbine end, and the compressed air will also generate heat (because the distance between the compressed air molecules becomes smaller, they will squeeze and rub against each other to generate heat energy). If this high-temperature gas enters the cylinder without cooling, it is easy to cause the engine combustion temperature to be too high, and then the gasoline pre-combustion will cause detonation, which will further increase the engine temperature. At the same time, the volume of the compressed air will also greatly reduce the oxygen content due to thermal expansion, which will reduce the boost efficiency and naturally fail to produce the power output it should have. In addition, high temperature is also an invisible killer of the engine. If you don't try to lower the operating temperature, once you encounter a hot weather environment or drive for a long time, it is easy to increase the probability of engine failure. Therefore, it is necessary to install an intercooler to reduce the intake temperature. After knowing the function of the intercooler, let's explore its structure and heat dissipation principle.
The intercooler is mainly composed of two parts. The first part is called Tube. Its function is to provide a channel to accommodate compressed air so that it can flow through. Therefore, Tube must be a closed space so that the compressed air will not leak pressure. The shape of Tube is divided into three types: square, oval and long cone. The difference lies in the trade-off between wind resistance and cooling efficiency. The second part is called Fin, which is commonly known as fins. It is usually located between the upper and lower layers of Tube and is tightly attached to Tube. Its function is to dissipate heat, because when the compressed hot air flows through Tube, the heat will be transferred to the fins through the outer wall of Tube. At this time, if there is air with lower outside temperature flowing through the fins, it can take away the heat and achieve the purpose of cooling the intake temperature. The structure that is formed by the two parts overlapping each other continuously until there are 10 to 20 layers is called the core, which is the main body of the intercooler. In addition, in order to allow the compressed gas from the turbine to have a buffer and pressure storage space before entering the core, and to increase the air flow rate after leaving the core, parts called tanks are usually installed on both sides of the core. Its appearance is like a funnel, and circular inlets and outlets are set on it to facilitate the connection of silicone tubes. The intercooler is composed of the above four parts. As for the heat dissipation principle of the intercooler, it is just like what I mentioned above. It uses many horizontal tubes to divide the compressed air, and then the direct cold air from the outside of the front of the car passes through the cooling fins connected to the tubes to achieve the purpose of cooling the compressed air, so that the intake temperature is closer to the outside temperature. Therefore, if you want to increase the heat dissipation efficiency of the intercooler, you only need to increase its area and thickness, increase the number, length and cooling fins of the tubes, etc., to achieve this goal. But is it that easy? Actually, this is not the case, because the longer and larger the intercooler is, the more likely it is to cause intake pressure loss, which is also one of the main issues discussed in this unit. Why does pressure loss occur? An intercooler that emphasizes performance must not only have good heat dissipation capabilities, but also reduce pressure loss. However, suppressing pressure loss and improving cooling efficiency are completely opposite in terms of techniques. For example, if an intercooler of the same size is designed entirely for heat dissipation, the tube inside needs to be made thinner and the number of fins needs to be increased, which will increase air resistance; but if it is designed to maintain the pressure level, the tube needs to be thickened and the number of fins needs to be reduced, and the heat exchange efficiency will be poorer in comparison. Therefore, the modification of the intercooler is not as simple as we think. Therefore, in order to balance cooling efficiency and pressure maintenance, most people will start with the tube and fins.
The next part is the fins. The fins of a general intercooler are usually straight strips without any openings, and the width of the intercooler determines the length of the fins. However, since the fins play a major role in the heat dissipation function of the entire intercooler, as long as the area of contact with the cold air is increased, the heat exchange efficiency can be increased. Therefore, many intercooler fins have various designs, among which the wave-shaped or so-called shutter-shaped fins are the most popular. However, in terms of heat dissipation efficiency, overlapping cooling fins are still the best, but the wind resistance they generate is also the most obvious. Therefore, they are more common in Japanese D1 racing cars, because these racing cars are not fast, but they need good heat dissipation to protect the engine running at high speeds. Modify the intercooler. [2]
Depending on the turbine capacity
After discussing the various modification theories of the intercooler, what are the matters that need to be paid attention to during the actual modification? Generally speaking, modified intercoolers are mostly divided into original exchange types and large-capacity kits that require a significant change in the pipe configuration. The specifications of the direct exchange type are similar to the original ones, the only difference is the different design of the internal tube and fins and a slightly wider thickness. This kit is suitable for vehicles that have not been modified from the original factory, or occasions where the modification is not large, and can stimulate the potential of the original engine. As for the large-capacity intercooler, in addition to increasing the windward area to enhance heat dissipation, the thickness will be increased to ensure constant temperature. Taking the intercooler produced by Haoyang as an example, the general type is about 5.5 to 7.5 cm (suitable for 1.6-2.0 liter vehicles), and the enhanced type is about 8 to 105 cm (suitable for vehicles above 2.5 liters). In addition, a large funnel-shaped air storage tank is used to minimize the resistance of airflow. Of course, the use of enhanced intercoolers is more suitable when equipped with medium and large turbines. For example, it is not recommended to use engines with turbines below 6, because the hysteresis will be more serious and not conducive to low-speed supercharging response. However, in NA-to-Turbo vehicles, it is better to have a larger intercooler because the cooling efficiency of the original design may not be enough. In addition, even if the supercharging setting is low, the intercooler cannot be omitted. After all, a lower intake temperature can not only extend the durability of the engine, but also help the stability of power output.
On the other hand, in addition to using air to dissipate heat, intercoolers also use water cooling. Toyota Mingji 3S-GTE is an example. Its main advantage is that its Cooler body is located just in front of the throttle, so the intake pipe is extremely short and has the characteristics of high response. In addition, the water itself has a very high constant temperature, which is also very helpful for the stability of the intake temperature, especially when there is no impact effect on the front of the car, such as in a traffic jam. However, since it needs to be connected to a dedicated water pump and a radiator, and the temperature reduction is not as large as direct air cooling, air-cooled intercoolers are still the mainstream.
Straightening is the priority
As for the installation position of the intercooler, it is generally divided into two types: front-mounted and top-mounted. In terms of heat dissipation, the front-mounted type located in the front bumper is of course better, but in terms of responsiveness, the top-mounted type is more advantageous. This is the direct effect of the boost caused by the short pipe. For example, in order to shorten the pipe of the front intercooler, the Impreza WRCar reverses the throttle to reduce the pressure loss caused by the long pipe. It is not difficult to imagine that the overall matching of the intake pipe is also a key point that must be paid attention to when modifying the intercooler. Therefore, when upgrading or installing an intercooler, in addition to paying attention to the size of the intercooler, the length of the pipe should be shortened as much as possible, and it should be straightened to reduce bends and welding points, etc. These are all ways to increase the air flow rate, because if there are too many welding points and bends, the smoothness of the air flow will be affected.
