By Steve Wittich When the second NTT INDYCAR SERIES practice sessions got underway at 1:10 p.m., the ambient temperature was 64F, and the track temperature was 100.4F.  The Rahal Letterman Lanigan Racing and Chip Ganassi Racing crews installed the new engines into No. 15 of Graham Rahal and No. 11 of Marcus Armstrong, and the…