Ok I know that nitrous requires colder plugs for safety but I want to know the reasoning behind it scientifically. What exactly do the colder plugs do? Just curious, want to know all i can and can't seem to find this.

 

Colder Plugs allow the electrode to be less exposed to heat. The porcilain on the plug doesn't go as deep into the body of the plug. This makes more contact with the head which draws heat away quicker. Hope this helps.

 

Mark said it very well. The basic "science" behind it is to disipate heat more quickly out of the cylinder to the heads. If you take a look at the picture I attached below, it shows a cut-away comparison of varying heat ranges. Hottest on the left and coldest on the right. Don't pay attention to the text in the picture...as different manufacturers have varying heat range numbers (ie NGK-higher # = colder, Champion lower # = colder). If you look at the colder plug, you'll notice that the insulator is very short which makes way for lots of surface area being available for thermal conduction. The heat is able to transfer to the metal casing of the plug and in turn to the cylinder head a lot more quickly then it would if the insulator nose had a larger surface area exposed to the combustion chamber atmosphere.



Nick