Spark Plugs

[Chaotic_Warlord]

I'm about to get the parts for a full service tune up and I have a question about spark plugs. I'm looking at some irridium plugs and they have different heat indexes. Now I'm not mechanically stupid and know what each part is and basically what to get but I'm confused about the heat index on spark plugs. Can someone please tell me the difference between a heat index of 7 and a heat index of 8 please. Whatis the difference, do you use one for turbo applications and one for NA applications, or is it rated by A/F mixture? Any help given will be much appreciated.

[2_Liter_Turbo]

Depends on the manufacturer. Autolight plugs for example; the higher the number the higher the heat range. NGK's on the other hand are the oppisite. The lower the number the hotter the plug. If you run a turbo I would run only Iridium Plugs. Platinum plugs, while good for N/A cars that are running a little rich, are horrible for a turbo car. Platinum plugs run very hot and if you are too lean on your A/F ratio then you can acually destroy your motor. Iridium plugs while having a superior spark, acually run "cooler" than platinum ones, thus lowering your chance to ruin your engine if you are too lean. Hope this helps.

[Chaotic_Warlord]

geez, why they gotta make choosing the right spark plug so damned difficult, I'll just get a set of Genso Platinum plugs, they have a solid reputation and I don't have any mods to my car yet so even though Irridium will be what I run with once I upgrade my ignition system and get enough money to turbo my car, Platinum plugs with do the job + some for right now.

[PalmerWMD]

Our new sponor has an application menu:http://www.sparkplugs.com/

Please use them.

Fred..

[gabossie]

Dan at Midway (another sponsor) can always hook you up with the right plugs too.

[Chaotic_Warlord]

Thanks for the help guys, especially with the links.