In 2-stroke karts’ engines, the temperature of the cooling fluid is a parameter that must always be kept under control since it has a decisive influence on both performance and reliability. The main accessory of making sure that the engine operates at the correct temperature range is obviously the radiator which, cannot do everything by itself, but must be managed correctly by the driver during the race even when the outside temperature drops.
After all, as it is true that the temperature should not vary too much, it is equally true that the engine should not be cooled excessively, because the risk of an engine seizure due to the incorrect operation amongst components that do not work at the right temperature is always a major concern.
Keeping the temperature below the safe parameters can become a problem in the winter months. In this case, it is of fundamental importance to choose a correctly sized radiator while also equipping yourself with a series of accessories that can reduce its cooling capacity if necessary.
Marco Malverti, owner of New-Line, a leading company in the manufacturing of radiators for racing karts, explains in detail how to manage your radiator during the winter period.
Choosing a radiator of the right size, based on the external temperature and the engine used, is essential. If it is too big or too small, controlling the temperature can become very difficult even with the right accessories. As an indication, we have created a reference table with the products of the New-Line Racing and EM Technology. Beyond the numbers, however, the principle to be taken into consideration is the following: just as in the summer with higher temperatures, one must rely on models with a larger surface (or with a double cooling circuit) to increase the heat exchange rate, in mid-seasons it is recommended to install radiators with a reduced core. For the single-speed categories, there are also product specifically designed for the winter. These are the smallest radiator models on the market today. Some of them are already equipped with a curtain, an accessory which, as we are going to see, provides the best solution to reduce the air impact on the core when the temperature drops significantly.
The choice of the right radiator, therefore, is very important to maintain the correct operating temperature of the engine, which varies according to the season. In fluid-cooled engines of FIA Karting OK Junior, OK and KZ categories and ROK and Iame single-brand series, the reference range for the water temperature goes from 48°C to 52°C in the summer while, in the winter period, it is recommended to stay between the 55°C e 60°C values. Then single-brand Rotax engines work at higher temperatures in all seasons, therefore, if we keep it between the 55°C and 60°C, we will have a water temperature which will allow to make the most of the engine.