Supercars drivers fear a hairy qualifying for the Sandown 500, with a borderline track surface and wet weather forecast creating a wild situation.
Track records fell on Friday at the Melbourne circuit, which seven-times champion Jamie Whincup said was "radically different" from his previous visits.
A thunderstorm, up to 10mm of rain and potential hail on a cold day present a huge challenge for the field on Saturday as they gear up for the first endurance event of the season.
Track owners Melbourne Racing Club made adjustments to the track to ensure its preparedness for the weekend, including additional safety measures at the notorious turn six.