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TKART magazine How To | All the accessories to lower the engine’s temperature
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Max Bernardi
12 August 2020
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Two-stroke engines, the most popular in the world of karting, are designed to work within a limited temperature range to offer the best performance. Values which for water-cooled 125cc engines are usually around 50 degrees, depending on the model. If the operating temperature exceeds 56 degrees, there will be a sudden drop in power until, in the most serious situations, it breaks down.
It is important to have a cooling system in good working condition, although this may not be sufficient in the summer with high atmospheric temperatures. Let us then find out together the different accessories which we can install to further lower the temperature of the cooling fluid when the normal radiator we usually use is no longer enough, and when the special “extra cooling” radiators are not sufficient to keep the engine’s operating temperature within the parameters indicated by the engine’s manufacturer.
In order to make the most of the KZ engine’s potential, the operating temperature must be maintained around 50°C. If during the summer period the water temperature increases and exceeds 56°C, a threshold beyond which the engine starts to lose power, it is recommended to install some accessories to lower the temperature.
Before analyzing the accessories that can help us lower the operating temperature of the engine, it is important to check the condition of the radiator. The primary issue that inhibits optimal functioning is limescale. To eliminate it, it will be necessary to add an anti-limescale detergent and start the kart’s engine at idle on the stand for ten minutes. This operation will dissolve the encrustations in the entire cooling system. The limestone layer creates a film between the radiator’s metal and the water, significantly decreasing the heat exchange between the two and the cooling efficiency. As for the core, on the other hand, attention must be paid to the state of the fins which compose it. In particular, it is necessary to straighten out the warped ones as they decrease the passage of air into the radiator. To analyze this topic in depth, we suggest you to read the article “Radiator maintenance”  where TKART, with the help of Marco Malverti owner of dove TKART and owner of New-Line Racing, a leading company in the manufacturing of radiators for karts, recommended all of these processes that are necessary to keep the radiator working efficiently.
Maintenance of the radiator is important to maintain its ability to cool the engine. At the end of each session it is good practice to blow the core with compressed air to remove debris and pieces of rubber collected while on the track.
Bent or warped fins must be straightened as they reduce the correct flow of air through the radiator core and reduce its ability to cool the water circulating inside it.
Limescale is an invisible enemy for the efficiency of the radiator. It forms inside the radiator and significantly decreases the thermal exchange with the water.
The purpose of the deflector is to speed up the disposal of hot air coming out of the radiator to improve the cooling capacity. The deflector is a shaped metal divider to be installed on the left side of the radiator (the one towards the fairing). The deflector must be installed just outside the edge of the radiator itself, a few millimeters away from the structure as it allows a channel and flow of fresh air which moves the hot air out and exiting the radiator’s core quicker. Additionally, the shape of the deflector moves the hot air away from the left rear wheel of the kart. This prevents the tire from undergoing an increase in pressure due to the overheating of the hub-rim-tire unit itself. Besides improving cooling, the deflector protects the radiator from debris thrown by the left rear tire, a considerable advantage in extending its life. The deflector can remain installed all year round, both in shifter and single-speed karts.
The purpose of the deflector is to speed up the disposal of hot air coming out of the radiator to improve the cooling capacity.
A passage channel is formed between the deflector and the radiator. The air that goes through has the task or blowing away the hot air coming out of the radiator.
If the deflector is installed adjacent to the radiator, it will not bring any benefit in the removal of hot air exiting the radiator’s core.
There are various types of deflectors. The model offered by GreyHound Racing Seat integrates a conveyor to increase the air flow.
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