I noticed when changing the time of day, my laptimes where different. Is this the case or is there something else I don't know about?
Not that I know... But yeah that happened to me as well.. especially when running at sunset or sunrise, when there are too many shadows on the asphalt (or when it's darker): my breaking points sometimes shift and I've to re-calibrate.
I'm not sure about that, but it can be that the temperature affects the lap times (after all the base is the isi engine). For sure the grip changes from practice session to qualifying, a sort of real road (as was in Gtr2)
Dawn and sunset are too dark in this sim to race in, since there is no real light simulation from headlights and track lights. I become depressive if driving in this dark brooding doomsday atmosphere. I only use morning, noon, afternoon, therefore.