Enthusiasts purchase aftermarket performance products for two main reasons: 1) to make the vehicle perform better and/or 2) to improve the vehicle’s toughness and reliability. For some enthusiasts, it’s all about performance; for others, reliability is the key. However, the vast majority of tuners address both performance and reliability in the tuning process. If you only address one of the two elements you end up with a fast car that’s very unreliable or a bulletproof vehicle that has lackluster performance. During the tuning process, an often overlooked but extremely important consideration is the vehicle’s cooling system. Whenever engine performance levels are increased (more horsepower is being made), the burden of the cooling system increases. This issue, we take an in-depth look at one of the critical components in the cooling system: the radiator. Understanding its purpose, its function and its design allows a tuner to make an educated decision about choosing the best performance radiator for their vehicle.
By Michael Ferrara
DSPORT Issue #105
Less than 40-percent of the heat generated through combustion gets turned into horsepower. Over 60-percent of the heat from the combustion of the air and fuel gets rejected out your exhaust pipe and through your vehicle’s cooling system. In simple terms, if your car originally produced 200 horsepower, the factory cooling system and exhaust system will reject about 300 horsepower worth of heat. When you turbocharge your vehicle and it is producing twice as much power, the cooling system and exhaust system now must reject 600 horsepower worth of heat. Thus, it is easy to see how easy it is to max out the capabilities of the factory cooling system.
Nearly every vehicle has the same basic components in their particular cooling system. First, there is a radiator. Second, there is either an electric or engine-driven fan that pulls or “pushes” air through the radiator. Third, there is a water pump. Fourth, there is a coolant system cap. Fifth, there is a thermostat. Sixth, there are hoses that provide the connections to circulate the cooling medium and finally there is the cooling medium (coolant) itself.
The purpose of the radiator is to reject the heat in the cooling system to the atmosphere. In engineering terms, a radiator is a basic heat exchanger. Heat exchangers are devices where two moving fluid streams exchange heat without mixing. The fans and the complementary shrouding assist in moving air across the core of the radiator. While the fans move the air, the water pump moves the coolant. The water pump puts the coolant in motion as it travels from the engine to the radiator and back into the engine. To keep the system at a desired pressure, the radiator cap keeps the system closed to the atmosphere unless the cooling system pressure exceeds this desired pressure. In most systems, a mechanical thermostat works as a temperature-dependent valve that blocks flow to the radiator when the engine is cold to speed up the engine’s warm up to normal operating temperature. Of course, connections between the various cooling system components must be made (radiator and cooling systems hoses make these connections). Finally, the coolant acts as the transfer medium that carries away the heat from the cylinders and allows it to be rejected out of the radiator.
Every single component on a vehicle is engineered with respect to a given design criteria. Your vehicle’s factory radiator is no exception. Whether its Nissan, Honda, Toyota, Mitsubishi or Subaru, the vehicle manufacturer will contract a company or subdivision to provide the lowest cost radiator that meets the minimum performance criteria. The performance requirements of the radiator are based on the needs of a factory-horsepower engine that encounters the normal challenges of regular use over the period of time that the OEM desires the radiator to function properly. As with any engineered device, the engineer will typically select a radiator that provides a slightly higher performance level than the minimum requires, as a factor of safety. Hence, if you have a new vehicle that is only making 5-to-10-percent more power than stock and you never push your vehicle, you really don’t need to invest in a high-performance radiator. However, if your vehicle is more than four years old or if you are generating over 20-percent more power than stock or if you do any type of track racing, you really need to consider a performance radiator upgrade.
After you understand the benefits of a performance aftermarket radiator, chances are that you’ll be in the market to purchase one for your vehicle. For most applications, you’ll have a number of options. You can narrow your choices by finding which manufacturers offer an application for your vehicle. Be sure to ask if the aftermarket radiator is a direct-fit. If the radiator is not a direct fit, be sure to ask the manufacturer what parts are needed to make the radiator fit. Once you determine which radiator manufacturers have a fit, you need to make sure that the radiator is designed for the use it will experience. Drag racing? High-performance street use? Road racing? Radiators designed specifically for drag racing may be too small for street use. As you may have guessed, radiators designed for road racing will typically have the highest cooling capacity.[pullquote]JUST BECAUSE ONE RADIATOR SEEMS TO BE “BETTER” IN ONE DESIGN PARAMETER DOESN’T MEAN THAT IT WILL PERFORM BETTER THAN ANOTHER RADIATOR[/pullquote]
There are many factors that go into the design of a radiator. In fact, there are complex equations that can determine the optimum design parameters for maximum efficiency. In designing a radiator, the designer can vary a number of parameters: core length, core width, core thickness, number of tubes, tube spacing and fin density, just to name a few. The important thing to remember is that just because one radiator seems to be “better” in one design parameter doesn’t mean that it will perform better than another radiator. It is the combination and balance of all the factors together that will determine the efficiency and performance capabilities of the radiator.
The engine in your car works best at a high temperature. When the engine is cold, components wear out easily, emits more pollutants, and the engine becomes less efficient. Thus, another important task of the cooling system is to allow the engine to warm up as quickly as possible, and then to maintain a constant engine temperature. The main function of a cooling system is to ensure that the engine runs at its optimum operating temperature. If the cooling system or any part of it fails, it will overheat the engine, which can lead to many serious issues.
Have you ever imagined what would happen if your engine cooling system did not work properly? Overheating can cause cylinder head gaskets to explode and even crack engine blocks if the problem is serious enough. And all this heat must be fought. If the heat cannot be removed from the engine, the pistons are literally welded to the inside of the cylinders. Then you just must throw the engine away and buy a new one. So, you should take care of your engine cooling system and learn how it works.
The radiator acts as a heat exchanger for the engine. It is usually made of aluminum and has many small diameter pipes with fins attached to them. Furthermore, it exchanges the heat of the hot water coming from the engine with the ambient air. It also has a drainage plug, an inlet port, a sealed cover, and an outlet port.
When the coolant cools after being in the radiator, the water pump sends the fluid back to the cylinder block, heater core, and cylinder head. Eventually, the liquid enters the radiator again, where it cools down again.
Read more about water pumps here.
Goto OKAYPARTS to know more.
It is a thermostat that acts as a valve for the coolant and only allows it to pass through the radiator when a certain temperature has been exceeded. The thermostat contains paraffin wax, which expands at a certain temperature and opens at that temperature. The cooling system uses a thermostat to regulate the normal operating temperature of the internal combustion engine. When the engine reaches standard operating temperature, the thermostat is triggered. Then the coolant can enter the radiator.
Read more about thermostats here.
Freeze Plugs: This is actually a steel plug designed to seal openings in the cylinder block and cylinder heads created during the casting process. In frosty weather, they can pop out if there is no frost protection.
Timing head/cover gasket: Seals major engine parts. Prevents mixing of oil, antifreeze, and cylinder pressure.
Radiator overflow tank: This is a plastic tank that is usually installed next to the radiator and has an inlet connected to the radiator and one overflow hole. This is the same tank that you pour water into before driving.
Hoses: A series of rubber hoses connect the radiator to the engine through which the coolant flows. These hoses can also start leaking after years of use.
Read more: The importance of an automotive thermostat in a car’s cooling system
To explain how a cooling system works, you must first explain what it does. It’s very simple – the car’s cooling system cools the engine. But cooling this engine can seem like a gigantic task, especially when you consider how much heat a car engine generates. Think about it. The engine of a small car traveling on a highway at 50 miles per hour will generate approximately 4,000 explosions per minute.
Along with all the friction from moving parts, this is a lot of heat that needs to be concentrated in one place. Without an efficient cooling system, the engine will heat up and stop running within minutes. A modern cooling system should ensure the coolness of the car at an ambient temperature of 115 degrees, as well as warmth in the winter weather.
The cooling system works by constantly passing coolant through channels in the engine block. Coolant, driven by a water pump, is pushed through the cylinder block. As the solution passes through these channels, it absorbs heat from the engine.
Leaving the engine, this heated fluid enters the radiator, where it is cooled by the air flow entering through the car’s radiator grill. The fluid will cool as it passes through the radiator, returning to the engine again to pick up more engine heat and carry it away.
There is a thermostat between the radiator and engine. Depending on the temperature, the thermostat regulates what happens to the liquid. If the fluid temperature drops below a certain level, the solution bypasses the radiator and is instead directed back to the engine block. The coolant will continue to circulate until it reaches a certain temperature and opens the valve on the thermostat, allowing it to pass through the radiator again for cooling.
It seems that due to the very high engine temperature, the coolant can easily reach its boiling point. However, the system is under pressure to prevent this from happening. When the system is under pressure, it is much more difficult for the coolant to reach its boiling point. Occasionally, however, pressure builds up and must be relieved before it can deflate the hose or gasket. The radiator cap relieves excess pressure and fluid by accumulating in the reserve tank. After the liquid in the storage tank has cooled to an acceptable temperature, it is returned to the cooling system for re-circulation.
Keep reading: How to detect cooling circuit problems
If you are looking for more details, kindly visit Engine Cooling System Manufacturer.