Dick Johnson Racing's Scott Pye set the pace during the opening practice session of the weekend at Phillip Island.
Pye, who had also topped a Friday session at the recent Castrol Edge Gold Coast 600, moved to the top with a 1:31.64s 12 minutes into the 20 minute hit-out.
Craig Lowndes ended up second ahead in his Red Bull Holden of James Moffat, James Courtney and David Reynolds.
“The car has obviously rolled out pretty good, but it was the same on the Gold Coast and we had a power steering failure in qualifying,” Pye told Speedcafe.com post-session.
“Hopefully we can keep it up there, but practice is one thing and qualifying tomorrow will be completely different.
“The Gold Coast got away from us and hopefully we can bounce back here.”
Cool and overcast conditions greeted the drivers for the morning session, with a gusting headwind down the front-straight adding to the challenge for drivers re-adjusting to the high-speed circuit.
“Going from the data that's what it looks like (a headwind) but I think I've still got more time to find in myself going into Turn 1,” noted Pye.
“I was being a bit soft into there, but the rest of the lap didn't feel too bad.
“We'll keep tuning it up through the day and see where we end up.”
Those to struggle with mechanical niggles during the session included Garth Tander, who reported intermittent power steering on his way to the 12th quickest time.
Shane van Gisbergen meanwhile ended up 15th having not set a flying lap until just two minutes remained.
The Tekno Holden was plagued by front-end vibrations throughout the 20 minutes, with the team changing the front-splitter mid-session.
“It wasn't good for us and we need to find out what was going on,” said Van Gisbergen.
The Kiwi also endured an off-track excursion while he battled the problems.
Whincup was another to taste the outfield – flying off at Turn 12 on his first flying lap.
Just under two seconds separated the field at the chequered flag with Dale Wood's Holden, which is trialling V8 Supercars' new-for-2015 camera and telemetry system today – slowest.
The second session will kick-off at 1145 local time.
PRACTICE 1 – Phillip Island
Pos | No. | Driver | Team | Car | Time | Gap |
1 | 16 | Scott Pye | Wilson Security Racing | Ford Falcon FG | 1:31.6148 | |
2 | 888 | Craig Lowndes | Red Bull Racing Australia | Holden Commodore VF | 1:31.7727 | 0:00.1579 |
3 | 360 | James Moffat | Norton Hornets | Nissan Altima | 1:31.7772 | 0:00.1624 |
4 | 22 | James Courtney | Holden Racing Team | Holden Commodore VF | 1:31.7791 | 0:00.1643 |
5 | 55 | David Reynolds | The Bottle-O Racing Team | Ford Falcon FG | 1:31.9888 | 0:00.3740 |
6 | 222 | Nick Percat | Walkinshaw Racing | Holden Commodore VF | 1:32.0360 | 0:00.4212 |
7 | 4 | Lee Holdsworth | Erebus Motorsport V8 | Mercedes E63 AMG | 1:32.0377 | 0:00.4229 |
8 | 5 | Mark Winterbottom | Ford Pepsi Max Crew | Ford Falcon FG | 1:32.0447 | 0:00.4299 |
9 | 8 | Jason Bright | Team BOC | Holden Commodore VF | 1:32.0571 | 0:00.4423 |
10 | 6 | Chaz Mostert | Ford Pepsi Max Crew | Ford Falcon FG | 1:32.0725 | 0:00.4577 |
11 | 36 | Michael Caruso | Norton Hornets | Nissan Altima | 1:32.1133 | 0:00.4985 |
12 | 2 | Garth Tander | Holden Racing Team | Holden Commodore VF | 1:32.1329 | 0:00.5181 |
13 | 17 | David Wall | Wilson Security Racing | Ford Falcon FG | 1:32.1753 | 0:00.5605 |
14 | 1 | Jamie Whincup | Red Bull Racing Australia | Holden Commodore VF | 1:32.1955 | 0:00.5807 |
15 | 97 | Shane Van Gisbergen | Team Tekno VIP Petfoods | Holden Commodore VF | 1:32.1973 | 0:00.5825 |
16 | 47 | Tim Slade | Supercheap Auto Racing | Holden Commodore VF | 1:32.2676 | 0:00.6528 |
17 | 14 | Fabian Coulthard | Lockwood Racing | Holden Commodore VF | 1:32.2776 | 0:00.6628 |
18 | 33 | Scott McLaughlin | Valvoline Racing GRM | Volvo S60 | 1:32.2912 | 0:00.6764 |
19 | 15 | Rick Kelly | Jack Daniel's Racing | Nissan Altima | 1:32.7301 | 0:01.1153 |
20 | 7 | Todd Kelly | Jack Daniel's Racing | Nissan Altima | 1:32.7618 | 0:01.1470 |
21 | 9 | Will Davison | Erebus Motorsport V8 | Mercedes E63 AMG | 1:32.8108 | 0:01.1960 |
22 | 18 | Jack Perkins | Team JELD-WEN | Ford Falcon FG | 1:32.8277 | 0:01.2129 |
23 | 23 | Russell Ingall | Repair Management Aust Racing | Holden Commodore VF | 1:32.8321 | 0:01.2173 |
24 | 34 | Robert Dahlgren | Valvoline Racing GRM | Volvo S60 | 1:33.5286 | 0:01.9138 |
25 | 21 | Dale Wood | Team Advam/GB | Holden Commodore VF | 1:33.5385 | 0:01.9237 |