Summer, with the colder air of the winter its going to run richer cause the colder air is denser. so its best to tune it when its hot out and the car runs hotter.that will be its most extreme weather situatiuon. If u tune it for the cold air when it gets hot out it might detonate from the hotter air.
Wait, are you sure about that? I thought cars run a little leaner in the winter because the air is more dense. Denser air is more oxygen-rich, so the AFR's should go up in the winter, right?
I'm confused.