How do I select the correct heat range when fitting Iridium Power to my vehicle?

In ordinary cars, use a spark plug with the same heat range as a normal spark plug. In highly tuned vehicles, select a heat range to suit the tuning level of the engine. (Ordinarily, the heat range of a highly tuned engine tends to be colder.)

Refer to the following table to compare the heat range of the Iridium Power and other spark plugs.