Selecting a spark plug can determine its calorific value based on the engine's compression ratio, speed, and air-fuel ratio.
The calorific value of commercially available spark plugs ranges from 5 to 13. The larger the value, the more "cold" the spark plug, the so-called cold type, high compression ratio engine requires the use of cold spark plugs. The smaller the value, the more "hot" the spark plug is, that is, the thermal type, low compression ratio engines use thermal spark plugs.
The colder spark plug is more sophisticated than ordinary products, so when the engine is running at high speed, it can ensure the accuracy and quality of ignition, thereby ensuring the maximum power of the engine at the limit. In addition, its resistance is also controlled to be very small, and the number of flashovers is not missing due to the increase in speed. Therefore, the use of a spark plug with a higher value is good for getting used to increasing the engine speed.