The #5 Mustang Sampling Racing Cadillac DPi of Christian Fittipaldi, Joao Barbosa and Filipe Albuquerque continued to set the pace on the opening day of the ROAR before the 24, with the trio doubling up in both sessions on Friday.
Albuquerque was the fastest on the day, with his best time of 1:37.196s enough to head the field, while co-driver Fittipaldi also set a time that would have been quick enough to lead the way.
CORE Autosport prevented a second consecutive Cadillac lockout by slipping their ORECA LMP2 machine into second place, with the quartet of Romain Dumas, Jon Bennett, Colin Braun and Loic Duval ending 0.107 seconds off the pace of Albuquerque.
Cadillac machinery did finish the session third and fourth, with the #10 Wayne Taylor Racing trio of Jordan Taylor, Renger van der Zande and Ryan Hunter-Reay ahead of the #90 Spirit of Daytona Racing trio of Tristan Vautier, Eddie Cheever III and Matt McMurry, although the #90, whilst in the hands of Cheever, caused a red flag when it stopped at turn six with twenty minutes remaining.
The #78 Jackie Chan DC Racing JOTA ORECA LMP2 of Alex Brundle, Antonio Felix da Costa, Ho-Pin Tung and Ferdinand Habsburg ended up fifth, ahead of the sister #37 of Daniel Juncadella, Lance Stroll, Robin Frijns and Felix Rosenqvist, while the fourth of the Cadillacs, the #31 Whelen Engineering Racing machine, ended seventh.
JDC-Miller Motorsports ended the day with eighth place with their #99 machine, with the two Tequila Patron ESM machines completing the top ten, the #22 ahead of the #2.
Fernando Alonso continued to gain experience of the Daytona International Speedway and the United Autosports Ligier LMP2 machine during the session, and the #23 he shares with Phil Hanson and Lando Norris ended up thirteenth fastest, behind the #6 Team Penske Acura and the #38 Performance Tech Motorsports ORECA.
GT Le Mans
The Porsche GT Team led the way in the second session on Friday, with the #912 of Laurens Vanthoor, Gianmaria Bruni and Earl Bamber finishing ahead of the sister #911 of Patrick Pilet, Nick Tandy and Fred Makowiecki.
The #912 set a best time of 1:44.065s to deny the #911 by just 0.076 seconds, while the leading Ford GT from Ford Chip Ganassi Racing, the #67 of Richard Westbrook, Scott Dixon and Ryan Briscoe ended up third, just 0.326 seconds back.
The #66 Ford GT of Joey Hand, Sebastien Bourdais and Dirk Mueller was fourth ahead of the #3 Corvette Racing machine of Jan Magnussen, Mike Rockenfeller and Antonio Garcia, with the sister #4 finishing seventh, just behind the #62 Risi Competizione Ferrari.
BMW continued to be off the pace of the rest of the class with their new M8 GTLM, with the #25 from BMW Team RLL of Connor De Phillippi, Alexander Sims, Bill Auberlen, Philipp Eng and Colton Herta more than three-and-a-half seconds off the pace, while the sister #24 had limited time on track, and was almost seven seconds down.
For the second time in the day, the #11 GRT Grasser Racing Team quartet of Rolf Ineichen, Franck Perera, Rik Breukers and Mirko Bortolotti led the way in GT Daytona in their Lamborghini Huracan GT3, with their best time of 1:47.175s 0.065 seconds clear of the second placed #59 Manthey Racing Porsche.
Magnus Racing, making their return to the IMSA WeatherTech SportsCar Championship in 2018, was third quickest with Markus Winkelhock, Andrew Davis, John Potter and Andy Lally in their #44 Audi R8 LMS GT3, with the #48 Paul Miller Racing Lamborghini of Bryan Sellers, Madison Snow, Bryce Miller and Andrea Caldarelli fourth.
The #29 Montaplast by Land Motorsport Audi placed fifth ahead of the #73 Park Place Motorsports Porsche and the #93 Michael Shank Racing Acura NSX GT3, with the #33 Mercedes-AMG Team Riley Motorsports Mercedes, the #14 3GT Racing Lexus RCF GT3 and the #86 Michael Shank Racing Acura completing the top ten.