— SALE ON IGNITION COILS AND HIGH IGNITABILITY PLUGS —
Use your unique promo code to receive your discount. Don't have a code already? Click here.
NGK.com specializes in hard to find NGK products. We are not NGK Spark Plugs USA. To contact them, click here.
Modifications are typically aimed at increasing power, which increases an engines operating temperature and the amount of excess heat a spark plug needs to remove. While an unaltered engine will run best with the spark plug heat range originally installed, modifications such as adding a turbo or supercharger, increasing compression, timing changes, using alternate fuels, and sustained use of nitrous oxide may necessitate the use of a colder plug.
A good rule of thumb is, use one heat range colder for every 75-100hp added. When making heat range changes, it is best to err on the side of too cold a plug - running a plug that is too cold will cause fouling, whereas running a plug that is too hot may cause severe engine damage.
Caution: The heat range numbering system used by spark plug manufacturers is not universal. See the article, "What is a Spark Plugs Heat Range?" for more information on how the heat range works and how to select a colder plug.