Is One Better Than The Other & Why?
Hotter sparkplugs CAN burn more fuel (or burn fuel better so more can be added), so if done right will make more power...within reason.
I agree. I’ve seen plugs in engines so hot you could weld with them. One example was a customer we did a 14:1 BBM for (I can’t remember what heads were on that engine but IIRC they were a set of Stage IV heads) and always on the invoice I write down the exact plug to start with. And of course, he didn’t want to dyno the engine.
Somehow, he got to the races (a divisional) and forgot to put spark plugs in it before he left. So he goes through the pits and borrows a set of plugs.
At 14:1 he should have been using a Champion C55 or equivalent. He ended up with an NGK that was the equivalent of a Champion 12!!!!!
Needless to say, he crapped that engine. So I had to leave the shop, drive to his place, grab his spare and drive to the track and help him swap them out.
The upshot is I couldn’t figure out how he killed the engine in two passes. Well, about 100 feet into the second pass.
Luckily, I grabbed some plugs off the shelf before I left the shop. I was screwing them into the back up engine and I asked him where the plugs were out of the dead engine.
He walked over to the garbage can and pulled out those welding electrodes he was using.
He was off by 5 ranges.