Helio Castroneves led the new Penske-Acura team to the head of the field in second practice for the Rolex 24 at Daytona on Thursday, sending out a warning shot to its Prototype rivals ahead of qualifying later today.

After seeing Rene Rast lead the way in FP1 for Mazda Team Joest, IndyCar veteran Castroneves was able to lead Penske to the head of the field with a fastest time of 1:37.036, finishing three-tenths of a second clear of Nicolas Lapierre in P2 for Tequila Patron ESM.

Fernando Alonso was able to enjoy his first decent mileage of the day after sitting out first practice following co-driver Phil Hanson's crash. The #23 United Autosports Ligier JS P217 finished 12th overall, with Lando Norris setting the fastest time out of the trio.

Porsche rose to the top of the order in GTLM as Patrick Pilet set the fastest time of the day so far, edging out Corvette's Jan Magnussen by just 0.068 seconds. Richard Westbrook and Joey Hand took third and fourth respectively in the two Ford Chip Ganassi Racing cars as the top five in the class were covered by less than three-tenths of a second.

In GTD, Alvaro Parente turned in the fastest lap for Michael Shank Racing in the #86 Acura NSX GT3, finishing two-tenths of a second clear of FP1 pace-setter Miguel Molina.