DAVID RUSSELL has topped the Porsche Paynter Dixon Carrera Cup Australia pecking order in practice at the VAILO Adelaide 500, setting the first ever lap below 80 seconds in a Porsche 911 GT3 Cup Car.

Russell's 1m19.9611s lap was set towards the end of today's second practice session and stands as the quickest ever Porsche lap of Adelaide's world-renowned street circuit.

It ensures the man currently second in the championship - and looking to defend that position from the chasing pack this weekend - started his weekend in the best possible way.

The TekworkX driver jumped to the top of the outright and Equity-One Pro class results with a string of flying laps late in the second session, held in perfect 23-degree conditions and in bright sunshine.

His 79-second flyer for a time saw him more than three-tenths clear of the entire field; the next 15 cars all covered by a second, however the gap closed late in the 25-minute session.

A late flyer from Jackson Walls saw the Objective Racing driver fall just short of beating Russell on Thursday, the Michelin Junior champ ending up second, just 0.06 seconds behind the pacesetter.

Champ-elect Harri Jones was third, while Ryder Quinn charged up the order into fourth place not far from the leading times.

The pace was hot in Adelaide as the field navigated both the circuit and themselves across the pair of incident-free sessions, the 29 cars - the largest ever Adelaide Porsche grid - making finding clear race track a significant challenge for everyone today.

Behind the top four, Glen Wood rounded out a strong day in fifth position with milestone man David Wall a stout sixth aboard his Wall Racing entry - the Sydneysider set to notch up his 250th Carrera Cup race on Saturday this weekend.

Gold Coast winner Bayley Hall was seventh, Dylan O'Keeffe eighth, Dale Wood ninth and Fabian Coulthard tenth.

Six different teams featured in the top 10 and while Sonic's best was Angelo Mouzouris in eleventh position, an 0.1 second gain for the Victorian would have seen him in the top five.

Such was the competitive nature of the field in practice, exactly one second covered the top 14 cars and just 1.2 seconds the top 18.

Having trailed the home-town hero in the first session, Adrian Flack returned serve on Sam Shahin in the second session to top the runners in SP Tools Pro-Am, the pair each less than two seconds away from the outright pace in the Pro field.

Stephen Grove - an Adelaide veteran - was third in Pro-Am and Dean Cook fourth, with Rodney Jane, Matt Belford, Marc Cini, Adelaide debutants Anthony DiMauro and Matt Slavin and Indiran Padayachee completing the order.

With practice now complete, attention turns to Qualifying on Friday morning with race one to follow in the afternoon.

Both races will be broadcast live on Fox Sports 506, Kayo and Sky Sports NZ.