What does colder heat range plug do?

[msfamilia]

I have read about it on ngk's site but I have a question......

does different heat range of plugs make the car run richer or leaner in anyway?

[PharmacyMSP]

colder plugs allow you to prevent detonation... its more about the spark happening b4 it is supposed to rather than the amount of fuel.

colder plugs are a must if you plan on raising the boost from stock.

[wicked]

a cooler heat range isn't exactly as it implies,it actaully has more to do with how fast heat is disipated from the plug.

a engine that tends to runn a cooler combustion chamber needs a hotter plug to keep the heat in to aid in it's combustion.

a engine like a turbo engine,or high compression engine need cooler plugs to help keep combustion temps under 2500 deg F,or else the engine has the same affects as if it were to lean,it detonates,negativly affecting the life of the engine,and producing unwanted gasses the are VERY negitive to the atmosphere and our health(Nox)