Racing Plug 5566

【NGK R0373A-11 Racing Plug 5566 ngk r0373a-11-5566】
Racing plugs recommended for two-wheeled and four-wheeled vehicles are available in various types for further performance improvement when used in races, circuit driving, or with increased engine output due to tuning.
Therefore, their shape may differ from the manufacturer's standard plug, and plug life or low-speed performance may be slightly sacrificed.
However, on the other hand, they are developed and designed to fully demonstrate their performance even in extremely tuned engines or under very severe operating conditions, and are available in a wide range of heat ratings.
Please select the appropriate plug for your individual engine to achieve its full performance.
Precautions when choosing a racing plug
Please determine the thread size, plug type, and shape from the part number of your genuine plug or the plug you are currently using, and then select the corresponding type.
Please refer to the manufacturer's website for how to choose the firing end 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 plug's firing end temperature within the optimal range.
Simply increasing the heat rating alone will not improve engine performance.
For mainly street use, numbers 7-8 are typically used; for track day specifications, 8-9; and for race specifications, 9-10.
The presence or absence of a resistor in the plug makes almost no difference nowadays due to the improved performance of ignition systems.
Resistor types will become the mainstream in the future.
Conversely, non-resistor types may cause engine problems in some models of some vehicle types.
In such cases, please be sure to use a resistor type.
*Images are for illustrative purposes only, and the design and specifications of the products shown are subject to change without notice. Please be aware of this.