Description

★ How to choose the shape of the ignition part

Considering the performance (ignitability) required of the plug, it is better if it protrudes into the combustion chamber (in other words, it is better if the spark position is closer to the center of the combustion chamber). The more the electrode protrudes, the more likely it is to receive heat and cause thermal problems (overheating, pre-ignition, deterioration of the outer electrode, etc.).
In general, the higher the performance and output of an engine, the higher the temperature in the combustion chamber and the stronger the vibration of the engine itself.
Therefore, as tuning progresses, we recommend a plug with a shape that prevents the insulator and electrode of the ignition part from being exposed to the combustion chamber.

Project (extrusion) type
Generally, it has a shape close to a normal plug. Suitable for less tuning such as muffler and air cleaner replacement. In addition, NA (naturally aspirated) engines can be expected to have high output in the entire range, and turbo cars tend to emphasize low-speed torque.
However, as the degree of tuning progresses, the thermal load and vibration applied to the plug also increase, so cracking of the insulator (insulator), melting of the electrode, breakage of the outer electrode, etc. are likely to occur.

Slant (diagonal) type
The insulator is further recessed and the electrode is also short and straight, and performance is demonstrated especially when the boost pressure is increased in a turbo car. Since the insulator is recessed into the metal fittings, it is less likely to be exposed to combustion gases. The outer electrode is also shorter and lighter, which not only prevents the electrode from heating but also increases its mechanical strength. In general, it is not possible to decide the plug from the output ratio with the normal engine, but if you want to increase the output by 50% or more in a turbo car, this type is recommended.
You can use it with peace of mind because it has a high safety margin in a highly supercharged engine where durability is emphasized.

Semi creeping type
In a way, it becomes the ultimate plug shape. If this type cracks the insulator and melts the electrode, it is almost impossible to deal with it from the plug side. However, durability and low-speed performance may be slightly sacrificed.