A “telling day” is in store for the Gen3 Supercars as they race for the very first time, around the gruelling streets of Newcastle.

Friday practice at the Thrifty Newcastle 500 was arguably a major success for the new breed, with few obvious technical problems despite the rushed nature of the rollout.

Indeed, even the recurrence of the wheel fitment issue at Walkinshaw Andretti United, which had reared its head at various teams during pre-season, should be a non-issue come qualifying later this morning, and fixes will be implemented to address cabin heat.

However, it will be mid-afternoon, when the Repco Supercars Championship field sets off for 250km over racing over 95 laps off the bullring that is the Newcastle East Street Circuit, when the next big hurdle has to be cleared.

While teams have attempted race simulations during shakedowns and testing, cars were not forced to run in close proximity to each other and the walls which help trap the heat and fumes, nor were they pounded over particularly tough kerbing.

Asked if today is the big test of reliability, Triple Eight Race Engineering Team Manager Mark Dutton told Speedcafe.com, “Definitely, definitely, because that is huge and no one that I’ve seen in these cars on a test day – or got feedback about – has done that long a race run.

“It’s tough and around here, it’s a pretty gruelling street circuit.

“Parts will be getting worn out, and even just normal parts; learning where sills rub more than others and comparing to what they did last year [for example] so that you really know the nuances of the new car.

“You have a little bit of an idea because of the testing that we’ve done so far, but until you do a full-on race with all the cars out there…

“There’s more heat, there’s more rubber, there’s more pick-up, there’s more everything, there’s more intensity, so tomorrow will be a very telling day.”

WAU Team Principal Bruce Stewart highlighted the close-quarters of racing as another area to watch.

“That’s when you see the rubbing and racing and bump and grind of Supercars,” he told Speedcafe.com.

“It’s going to be tight out there and when people are fighting for the same space, you’re always going to have moments when someone’s got to yield or there’s going to be contact, and that makes it exciting.”

Ironically for Triple Eight, the most notable issue which Shane van Gisbergen had in his #97 Red Bull Ampol Camaro was a brief gear selection drama, just before he set the lap time which was good enough for second in the Friday timesheets.

That transaxle is one of the very few carryover parts from Gen2 and while Dutton says the team will analyse the problem, he was overwhelmingly pleased with how smoothly the opening day went.

“It was awesome,” declared Dutton.

“Obviously up and down the field, drivers were driving very smart and sensibly, and working up to it. It’s not like they were avoiding the kerbs, but everyone was very sensible.

“They didn’t go and smash them straight away; they felt what the capability of the car is, so I think it’s pretty impressive for the whole category.

“I haven’t had too many reports of major issues, so it’s very successful for everyone.”

Triple Eight scored second and 10th in Friday practice thanks also to the efforts of Broc Feeney, while WAU’s Chaz Mostert (Mobil 1 Optus Racing) and Nick Percat (Mobil 1 NTI Racing) ended up third and sixth, respectively.

“It is only the first day, but importantly, the cars are all straight and we had a chance to test them out and spend some good track time understanding this new Gen3 Mustang,” remarked Stewart.

“For me, if the cars are straight and you’ve got two in the top 10, you’re reasonably happy, but there are no points.

“It was a reasonable start, but we’re not going to get ahead of ourselves.”

Qualifying for Race 1 starts at 11:15 local time/AEDT, followed by a Top 10 Shootout at 12:35 local time/AEDT.