You're going to want a little more split in your on/off cycle. On and Off at 170 is going to leave the lower fan cycling a lot. Maybe try on at 175 and all off at 165-170?
ya that makes sense. it is adjustable so i will play around and see what works best. it also has an override option. it has a wire that you can run to a switch and run both fans manually. that will be nice at the track in the staging lanes.