ech

I assume if you change plugs (7s, 9s, 11s) that this would have an effect on ignition maps, but I have not seen anything written on this subject.

I've seen different maps for different setups, but no one ever mentions what plugs the maps are tuned for. Am I wrong in thinking they might have something to do with ideal timing? If they do can someone explain how to account for this in maps (other than to dyno tune for best HP).

I'm posting the thread to this forum, because people here seem more interrested in this kind of thing.

Bucrx7

Spark plugs shouldn't change your ignition timing/map. People use difference heat range/type plugs because it's better for their mods. More mods/hp/boost you run the more colder the heat range you want. If you are running a single turbo I assume you'll throw in 10s-11s plugs before you dyno tune your car.

ech

That's what I have heard, but I'm afraid I don't fully understand - or don't remember :\

Does colder refer to the amount of spark, or the amount of heat that the plugs retain? In either case assuming all else is static (hah) if you are running colder plugs shouldn't you be able to advance the timing a bit? Or vice versa?

peejay

It's the amount of heat the spark plug retains.

The problem is that if you run plugs that are too hot, they can cause preignition (the heat of the spark plug is enough to light the fire) or in the best case you will wear them out very rapidly.

Spark advance SHOULDN'T be affected... but obviously you should choose the proper heat range. I like to get the coldest ones that I can use, without them fouling out.

ech

Thanks, that makes sense.