I used to race 1/8 buggies and we used to run our engines around 220. I have a Caliber now and I am still breaking in the engine so I'm still running it on the rich side. One good old fashion way to check it is to spit on your finger and touch the head by the glow plug, if it just sits there, you can lean out, if it starts to sizzle alittle, your pretty good, and if it just dissappears instantly, your to hot.