The #7 Toyota TS050 HYBRID topped all four sessions of the official pre-event test ahead of this week's Sebring 1000 Miles round of the World Endurance Championship.
Mike Conway was fastest in three of the sessions and Kamui Kobayashi the other aboard the Toyota TS050 HYBRID they share with Jose Maria Lopez, who was on Formula E duty in Hong Kong and not at the test.
Conway ended up fastest over the two days of testing with a 1m41.152s set on Sunday afternoon.
Fernando Alonso was quickest in the #8 Toyota he shared with Kazuki Nakajima in the absence of Sebastien Buemi, who was also racing in FE this weekend.
Two-time Formula 1 world champion Alonso ended up on a 1m41.204s set, like Conway's time, on Sunday afternoon.
Conway, who unofficially broke the Sebring lap record, said: "It's a nice feeling to go around Sebring quicker than anyone has before.
"There could be even more to come during the race week; we might be able to go quicker again.
"The main thing this weekend was to get ourselves well prepared for race week and we have done that."
The fastest privateer LMP1 lap around the Sebring International Raceway, which hosts the eight-hour WEC round on Friday, was set by SMP Racing newcomer Sergey Sirotkin.
The ex-F1 driver recorded a 1m42.357s on Sunday morning aboard the #17 BRE-AER BR1 to outpace team-mate Brendon Hartley, who has also joined the team for Sebring, by three tenths.
The two Rebellion-Gibson R-13s were fifth and sixth, Gustavo Menezes posting the team's fastest lap with a 1m42.926s
Nyck de Vries topped the LMP2 times aboard the Racing Team Nederland Dallara-Gibson P217 with a 1m47.086s.
That put the Dutchman just under one hundredth ahead of Nicolas Lapierre aboard the Signatech Alpine ORECA-Gibson 07, which has switched to Michelin tyres from Dunlop for Sebring.
Third fastest was Matthieu Vaxiviere in the TDS Racing ORECA.
The Jota Sport-run Jackie Chan DC Racing ORECA squad, which leads the LMP2 points, did not take part after running in a private test organised by Toyota at the start of last month.
Porsche ended up quickest in GTE Pro when Richard Lietz improved to a 1m57.302s on Sunday afternoon aboard the #91 factory 911 RSR.
That bettered Andy Priaulx's 1m57.411s set on Sunday morning aboard the #67 Ganassi Ford GT.
Davide Rigon was third fastest aboard the quickest of the factory AF Corse Ferrari 488 GTEs on a 1m57.771s.
Billy Johnson was fourth in the second of the Fords on a 1m58.078s, which was just six hundredths up on the Ferrari of James Calado.
Sixth quickest was Nicky Catsburg in the fastest MTEK BMW M8.
Matteo Cairoli was fastest in GTE Am in the best of the Dempsey-Proton Porsches.
The Sunday morning session was interrupted when the GTE Am Project 1 Porsche with Jorg Bergmeister driving caught fire and suffered significant damage.
The team said it would "analyse the status of the car and work on a solution for the upcoming week".
Free practice for the WEC round, which shares the bill with the Sebring 12 Hours IMSA SportsCar Championship enduro, begins on Wednesday and the race start is at 4pm local time on Friday.