Brisk and NGK are one of the world best spark plugs manufactures. Here's a short explanation of heat ranges and what they mean.
Spark plug heat ranges are sometimes a mess, and in addition to the stock characteristics of an engine (like combustion chamber, head design, compression), the amount of additional power also effect the correct rating. As a rule of thumb, go with the stock rating for a stock engine, a notch colder for an averagely tuned engine and two or three colder for some insane builds. Both of our main brands - Brisk and NGK - make great plugs, where the highly heat-resistant iridium models are the most popular plugs.
In short, the heat rating of a spark plugs tells you how well the plug center electrode can dissipate heat. A colder plug conducts heat away more effectively, resulting in - hooray, a colder plug. A hotter plug on the other hand has a longer way the heat needs to travel before it can dissipate into the head, so it runs a little hotter.
In Brisk heat ratings a higher number means a hotter plug: DOR14 is hotter than DOR12. In NGK the ratings go the opposite way, so a BKR7EIX is colder than a BKR6EIX. We always keep the usual plugs on the shelf in our stock, so we can offer the fastest shipping.
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