On the first day of comparative testing for the 2016-spec LMP1 hybrids it was Porsche that topped the order at Circuit Paul Ricard.
Neel Jani’s 1:37.487s lap during the night-time session saw the #2 Porsche 919 Hybrid go quickest overall.
The #2 car led all three practice sessions, with Jani setting the fastest lap in the morning and evening and Romain Dumas topping afternoon proceedings.
Jani, Dumas and Marc Lieb were the only Porsche drivers to drive on Friday; world champions Mark Webber, Brendon Hartley and Timo Bernhard will put the #1 car through its paces on Saturday.
The second quickest car on day one was the #5 Toyota TS050 hybrid which set a 1:38.374 courtesy of Kazuki Nakajima during the night.
Audi’s #7 R18 e-tron quattro ended Friday third fastest overall thanks to a 1:39.393 from Benoit Treluyer.
That put Toyota 0.887s off the pace while Audi sat 1.906s behind the leading Porsche.
The privateer LMP1 battle was closely fought between Rebellion Racing and Bykolles, but after three sessions it was the #12 Rebellion R-One of Nicolas Prost that prevailed with a 1:42.417.
In LMP2, Jonny Kane recorded the fastest lap of the day in the Strakka Racing-entered Gibson 015S-Nissan. Kane produced a 1:46.976 in the afternoon session to put the British team on top, eclipsing the 1:47.340 morning benchmark set by Nelson Panciatici in the Baxi DC Racing Alpine A460-Nissan.
GTE-Pro was led by the #51 AF Corse Ferrari 488 of Gianmaria Bruni, while Pedro Lamy topped the GTE-Am category driving the #98 Aston Martin Vantage.
The four classes will regroup for the final day of the Prologue test with two sessions scheduled to start at 09:00 and 14:00 (CET).