Subaru do Motorsport team's efforts to elevate to second place in the CAMS Australian Rally Championship continue apace in South Australia this weekend, in the penultimate round of the 2019 series.

With just two short stages remaining in today's Heat 1 of the Adelaide Hills Rally, the Orange Motorsport-prepared All-Wheel Drive Subaru WRX STI proved its solid credentials across this morning's first four stages.

Heat 1 is a marathon 10 stages that began at 8am and won't see teams back at service until after 9pm tonight.

Molly Taylor and co-driver Malcolm Read grew in confidence throughout the morning, despite at times torrential showers and the added challenge of unfamiliarity with several new and altered stages on often fast, sweeping shire roads.

Consistent second places across the first four morning stages were clear proof of the team's potential.

This afternoon's four stages proved more testing, with technical gremlins relegating Taylor and Read's placing to third overall ahead of two short night stages.

Despite the challenges, the pair acquitted themselves well to achieve third on their first run through the rally's longest stage, the 30.94 kilometre SS6 Monarto 1.

They recovered further to take second on the second run through Monarto, holding third place overall.

Heat 1 concludes tonight with two 1.6 km runs at The Bend Motorsport Park, taking the total competitive distance for the day to 107.5 km.

Molly said: "We felt after the first couple of stages this morning that the car had a lot more in it.

"That gave us the confidence to start pushing a bit harder and step it up to another level.

"That paid off for us until we had some technical glitches this afternoon, but overall, not a bad Heat so far."

Tomorrow's Heat 2 covers an additional 10 stages over 97.37 km.

It concludes with a podium presentation at Mount Barker at 5.30pm.