Temp is just a guide. It was said on the 1st page find someone who can help you tune and then you will know how it's suppose to sound. Tune for smoke and performance. That means that it should idle well and spool up nice and then back down. Tuning a nitro engine can be difficult if you don't know what you are doing but watch an experienced tuner dial it in and learn. IMO 220-280 is acceptable as long as it sounds good and has a little bit of smoke. I have ran engines warmer than that and I knew the consequences but never colder than 220, it's just as hard on an engine being too cold as too warm. Different fuels will smoke differently too depending on the oil package