Racing Plug 4940

【NGK R0373A-10 Racing Plug 4940 ngk r0373a-10-4940】
Racing plugs, recommended for two- and four-wheeled vehicles, are designed in various types to further improve performance when used in races, circuit driving, or with increased engine output due to tuning.
Therefore, their shape differs from the manufacturer's standard specified plugs, and plug life and low-speed performance may be slightly compromised.
However, on the other hand, they are developed and designed to fully demonstrate their performance even in highly tuned engines and under extremely severe operating conditions, and are set with a wide range of heat ratings.
Please select the appropriate plug for your individual engine to achieve full performance.
Points to note when choosing racing plugs
From the part number of your genuine plug or the plug you are currently using, determine the thread size, plug type, and shape, and select the corresponding type.
Please refer to the manufacturer's website for how to choose the igniter shape.
The heat rating needs to be selected considering the increase in combustion temperature due to increased engine output and operating conditions, in order to keep the igniter tip temperature within the optimal range.
Simply raising the heat rating alone will not improve engine performance.
Generally, heat ratings 7 to 8 are used for street use, 8 to 9 for track day specifications, and 9 to 10 for race specifications.
The presence or absence of a resistor in the plug makes almost no difference nowadays due to improvements in ignition system performance.
Resistor types will become the mainstream in the future.
Conversely, non-resistor types may cause engine trouble in some models of some vehicle types.
In such cases, always use a resistor type.
* The image is for illustration purposes only, and the design and specifications of the products shown are subject to change without notice. Please understand.