The #2 Sonic Motor Racing Services driver clean swept both of Sunday's 18-lap races for his first wins in the series, following a second place in Race 1 on Saturday.
Sunday's Race 2 saw Hillyer take the lead early from polesitter and Race 1 winner Zak Lobko, who was also jumped by Eddie Beswick before a tussle with Jake Santalucia, who passed Lobko for fourth on Lap 3.
Lobko returned fire, retaking third place from Santalucia who became locked in a four-way battle led by fifth-placed Thomas Davies, Xavier Kokai and Conor Somers – the latter having charged from 13th to seventh place in only ten laps.
The quartet would finish in that order, behind race winner Hillyer and runner up Beswick.
Kyle Evans and Harrison Sellars came home eighth and ninth, fending off a charging Daniel Frougas, who recorded a tenth-place finish after starting in 17th.
Race 3 saw Hillyer engaged in an enthralling wheel-to-wheel battle with both Lobko and Kokai, the trio brought together after a Safety Car period on Lap 7.
When the green flag was waved on Lap 10, it was Kokai – who'd started sixth – who capitalised, charging his way to third before adding more pressure to Hillyer as both he and Lobko looked for a way past the race leader.
Despite the dogfight, Hillyer maintained took the Race 3 victory from Lobko and Kokai, with Davies, Somers, Frougas, Evans, Sellars, Lachlan Strickland and Imogen Radburn making the Top 10.
Hillyer leads the AFFS standings on 56 points from Lobko (51) and Kokai (34 points).