Jayden Ojeda topped Thursday's testing at Mandalika ahead of GT World Challenge Asia powered by AWS's first-ever appearance in Indonesia this weekend.
Given the lack of previous running it was understandable that lap times improved across the first three sessions before heavy rain arrived a little after the final test began.
Craft-Bamboo's Pro-Am Mercedes-AMG set its fastest time in the third session, just like the rest of the combined top eight. Ojeda's 1m28.584s was a tenth faster than Alessio Picariello managed in Origine's Porsche, while leading Silver-Am contender Maxime Oosten slotted KRC's BMW into third overall.
The combined times were perhaps a little unfair on Picariello who set the fastest individual times in sessions one, two and four.
JMR's Corvette were next up thanks to Jordan Love and Ben Green, who joins Sepang race winner and championship leader Prince Jefri Ibrahim for the first time this weekend.
Phantom Global's Dorian Boccolacci, Ralf Aron (Climax Racing) and the top Silver class entry - FAW Audi Sport Asia Team Phantom - rounded out the first eight.
Just four cars set their best times in the final session before the rain fell. The fastest of them was Absolute Corse's Thierry Vermuelen in ninth overall, while his team-mate Edoardo Mortara - albeit driving a Lamborghini - set his entry's best lap in test #2.
Further back, Ben Porter (AMAC Motorsport) recorded the fastest Am class time by three tenths from EBM's Mercedes-AMG.
Official track action begins on Friday with Free Practice and the Bronze Test preceding Pre-Qualifying.