Sonoma: Castroneves tops 2nd IndyCar practice
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| Helio Castroneves |
Helio Castroneves', driving the No. 3 Hitachi Team Penske car, topped the time chart in the second 45-minute practice session for the GoPro Grand Prix of Sonoma with a lap of 1 minute, 18.6582 seconds on the 2.385-mile, 12-turn road course.
Ryan Briscoe, driving the No. 8 NTT DATA Chip Ganassi Racing car, was second (1:18.6920) and Ryan Hunter-Reay, who was quickest in the morning session, was third (1:18.7984) in the No. 28 DHL Andretti Autosport car.
Reigning series champion Scott Dixon was fourth and Power was fifth.
The three rounds of qualifying for the 85-lap race are live on NBCSN at 7:30 p.m. (ET).
Results
| Pos | No | Name | Time | Diff | Gap | FL | Laps | Speed | Engine |
| 1 | 3 | Helio Castroneves | 1:18.658 | 0.000 | 0.000 | 14 | 16 | 109.156 | Chevy |
| 2 | 8 | Ryan Briscoe | 1:18.692 | 0.0338 | 0.0338 | 18 | 18 | 109.109 | Chevy |
| 3 | 28 | Ryan Hunter-Reay | 1:18.798 | 0.1402 | 0.1064 | 11 | 12 | 108.962 | Honda |
| 4 | 9 | Scott Dixon | 1:19.030 | 0.3722 | 0.2320 | 13 | 13 | 108.642 | Chevy |
| 5 | 12 | Will Power | 1:19.037 | 0.3788 | 0.0066 | 11 | 14 | 108.633 | Chevy |
| 6 | 11 | Sebastien Bourdais | 1:19.111 | 0.4523 | 0.0735 | 12 | 16 | 108.532 | Chevy |
| 7 | 67 | Josef Newgarden | 1:19.156 | 0.4983 | 0.0460 | 16 | 17 | 108.469 | Honda |
| 8 | 2 | Juan Pablo Montoya | 1:19.205 | 0.5470 | 0.0487 | 13 | 13 | 108.402 | Chevy |
| 9 | 10 | Tony Kanaan | 1:19.231 | 0.5723 | 0.0253 | 11 | 15 | 108.367 | Chevy |
| 10 | 25 | Marco Andretti | 1:19.262 | 0.6035 | 0.0312 | 14 | 15 | 108.325 | Honda |
| 11 | 34 | Carlos Munoz | 1:19.400 | 0.7423 | 0.1388 | 15 | 15 | 108.135 | Honda |
| 12 | 83 | Charlie Kimball | 1:19.424 | 0.7663 | 0.0240 | 16 | 17 | 108.103 | Chevy |
| 13 | 77 | Simon Pagenaud | 1:19.442 | 0.7840 | 0.0177 | 11 | 13 | 108.079 | Honda |
| 14 | 19 | Justin Wilson | 1:19.449 | 0.7905 | 0.0065 | 15 | 18 | 108.070 | Honda |
| 15 | 14 | Takuma Sato | 1:19.513 | 0.8546 | 0.0641 | 14 | 14 | 107.983 | Honda |
| 16 | 15 | Graham Rahal | 1:19.619 | 0.9608 | 0.1062 | 18 | 19 | 107.839 | Honda |
| 17 | 20 | Mike Conway | 1:19.646 | 0.9876 | 0.0268 | 12 | 19 | 107.802 | Chevy |
| 18 | 17 | Sebastian Saavedra | 1:19.690 | 1.0316 | 0.0440 | 14 | 16 | 107.743 | Chevy |
| 19 | 27 | James Hinchcliffe | 1:19.783 | 1.1249 | 0.0933 | 16 | 17 | 107.617 | Honda |
| 20 | 7 | Mikhail Aleshin | 1:19.813 | 1.1551 | 0.0302 | 16 | 16 | 107.576 | Honda |
| 21 | 18 | Carlos Huertas | 1:19.840 | 1.1816 | 0.0265 | 18 | 19 | 107.540 | Honda |
| 22 | 98 | Jack Hawksworth | 1:19.991 | 1.3330 | 0.1514 | 17 | 18 | 107.337 | Honda |