colder plugs

[dstang01]

what is plug heat range, what exactly is the function of plug heat range, and how do different heat ranges affect performance? Just looking for a general explanation thanks

 

[Vipersix]

First you must realize that spark plugs have two basic functions: 1) igniting the fuel/air mixture (i.e. spark) 2) removing heat.

Basically, as compression increases, the energy involved in the spark process is also increased to overcome the additional forces in the combustion chamber. As the energy is increased, there is obviously more heat involved and thus the plug needs to be "colder" to remove the extra heat. The idea is to remove enough heat from the tip of the plug in order to prevent pre-ignition while leaving it hot enough to prevent fouling.

So performance gains/losses are really negligible. There is really only one heat range that will be acceptable to your application. Going too cold will dissipate too much heat and will foul the plugs, thus decreasing performance. While going too hot will not remove enough heat and will cause pre-ignition, another performance decreasing option.

 

[dstang01]

First you must realize that spark plugs have two basic functions: 1) igniting the fuel/air mixture (i.e. spark) 2) removing heat.

Basically, as compression increases, the energy involved in the spark process is also increased to overcome the additional forces in the combustion chamber. As the energy is increased, there is obviously more heat involved and thus the plug needs to be "colder" to remove the extra heat. The idea is to remove enough heat from the tip of the plug in order to prevent pre-ignition while leaving it hot enough to prevent fouling.

So performance gains/losses are really negligible. There is really only one heat range that will be acceptable to your application. Going too cold will dissipate too much heat and will foul the plugs, thus decreasing performance. While going too hot will not remove enough heat and will cause pre-ignition, another performance decreasing option.

Thanks alot, this is a great explanation! The reason Im curious is because I was considering nitrous, and it is recommended to go a heat range or two colder than stock plugs. I was worried that doing so would negatively affect N/A driving.. and I will be driving my stang off the spray much more than on (I might spray a few times on the weekends) Would going a range or two colder than stock cause any fouling problems when running off the bottle?

 

[Vipersix]

Pretty much the only way to determine that is to try it. Put the new plugs in and run it for about 100 to 200 miles and then pull the plugs and look at the tip. If they're oily and black you've gone too cold. If they are mostly just crispy with that white residue powder on them you're money!