A spirited series of drives allowed North Canterbury teenager Jackson Culver to snatch the lead in the Australia's junior Formula 4 championship with one round remaining.

His race win, two runner-up spots, pole and two fastest laps at round four of the five round series at the Bend International Raceway in South Australia, secured him a narrow one-point lead in the Gen 1 AU4 championship with the final less than a month away in Queensland.

The 14-year-old Rangiora High School student says the solid work in testing paid dividends on race day.

"I'm satisfied with the round win. We put a lot of hard work in on the Thursday and Friday to get the car where it needs to be, but that's what you have to do," said Culver who relies on simulator training back home to prepare, unable to travel to Australia for testing between rounds.

"The track and the simulator were pretty close to identical so then it was just figuring out how fast you can take it in the real car and learning the track a bit better."

But it wasn't all smooth sailing as a mechanical issue on Saturday prevented him from setting a competitive lap time and he was forced to start the opening race last, in sixth position of the Gen1 cars.
"The first qualifying was a little frustrating because we had a gearbox issue where it just wouldn't downshift so we lost the entire qualifying. We had just one lap but it was super low because we had the down change problem but I was pleased to come back in Q2 and get pole by two-tenths."

He said he was just sitting in the car trying to put his mind at ease, memorising the lap and figuring out what he had to go out and do.

"The boys did a really hard job to get the gearbox fixed in time so I was super happy," he said.

Off pole for the final race Culver struggled against Wilson on older tyres.

Drivers are only permitted one set of tyres for the weekend, and must manage them through qualifying and all three races.

Championship point leader going into the Bend, Aussie Lewis Gotch, was disqualified for changing his tyres before the race elevating Culver to the top of the championship by the slimmest of margins.

With just 13 points covering the top three going into the final round, it will be a winner-takes-all grand finale at the Queensland Raceway, on September 25 – 27. Culver has won two of the four rounds.

"It'll be quite a tense last round to be honest, but I really hope we can come out on top and I'll be putting all the work in and go back out in four weeks and see what we can," said Culver.

The older series Gen1 Formula 4 cars run behind a grid of modern Gen2 machines. Drivers must be over 15-years of age to race the top category.