It depends on which engine you have. Every engine has a plug they recommend and the plugs also have different heads, different lengths and different engine temps.
i have the 3.3 and my normal air temp is around 86f and my engine temp normally runs around 240-260f at a good performance level. is the medium or hot plug better? i run 20% nitro.
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also the coil tends to warp when i run it a little leaner or once the temp goes up. guess thats normal?
The coil should never warp, that's from lean running. A good plug should last you 1 gallon in those conditions.
A medium plug is generally going to give you better high end performance, with a little less throttle response.
The hot plug is more suited for a lot of on and off throttle, and helps your engine idle better, while losing a little off the top end. I run hot in my small blocks because I like a nice smooth idling engine.
It all varies between manufacturers though, some plugs are better than others.
IMO ,I run hot plugs with small blocks ,cold plugs with big blocks.. This is just the way I've had the best luck and longest life with plugs. I run the os plugs and they seem to last the longest lc3 or lc4 for my 3.3