For two days on the streets of downtown Detroit, the red #31 Cadillac Whelen V-Series.R was the fastest car in IMSA GTP from the moment it rolled out of its transporter on Thursday.
And after finally kicking down the door to its first win of the 2026 season, Action Express Racing, Jack Aitken, and Earl Bamber are firmly in the drivers seat going into the second half of the WeatherTech SportsCar Championship.
“As soon as it hit the track, it was super-quick,” Bamber said after winning the Chevrolet Sports Car Classic. The veteran driver from New Zealand put the #31 Cadillac on the pole on Friday – his first IMSA pole since the 2015 Petit Le Mans – and led the first 27 laps of Saturday’s race.
“We sort of built on what we had last year, we knew that it was good. And I managed to pull a gap (in the first stint), and just managing the energy,” Bamber recounted of his opening stint.
“We had a little bit of a tricky moment with the #23 (Aston Martin Valkyrie). I think they had a drive-through or something like that; I don’t really know why they were near us. But we sort of started to get boxed behind them.”
Instead of getting stuck in traffic and potentially losing their advantage, the Cadillac Whelen team brought Bamber into the pits a bit ahead of schedule while they had a comfortable gap. “We were one of the only cars to also change right-hand side tyres, and we were just making the job easier at the end of the race if the yellows came for Jack. Which, was the right call,” Bamber continued.
“Our team is great with the strategy at the moment. Whatever gets thrown to them, they know how to react. And the fact that we can take tyres when no one else could just shows what they’re doing, in the lane and on the strategy stuff. And then, Jack just did a faultless drive to the end.
“I think that’s probably a pretty perfect weekend.”
With his two fresh right-side tyres providing extra grip down the stretch, Aitken led the final 46 laps (he and Bamber combined led 73 out of 82). But as the last 20 minutes were peppered with incidents and Safety Car interventions, Aitken would lose a 14-second lead and instead had to nail down two perfect restarts to secure the win.
They were the headlining performers in a double victory for GM, right at the doorstep of their famous Renaissance Center complex. Cadillac won in GTP, and Corvette Racing won in GTD Pro for Chevrolet. It was GM’s first clean sweep of an IMSA race since the 2018 Grand Prix of Long Beach.
“I think it’s a win that we’ve been searching for for a while, since this program started,” remarked Aitken, the new GTP Drivers’ Championship leader. “With Detroit being the home for GM, for Cadillac, for so many of the people on the programme, it was very meaningful.
“We’ve come close with podiums, but to get the win – on the same day that the Corvettes managed to do the same, it’s pretty overwhelming, but amazing!
“Very grateful to have the team around me that I do. From Earl, who was just incredible with his pace this weekend and from his pole position, to handing me the car in the race in the lead, it made my life very easy, which was nice. But the car was very, very impressive as well. We had a very good car from the get-go. The Whelen Cadillac guys really nailed it.
“There was no cruising, because on a track like this, when you start to ease up, it can bite you in the a— quite quickly.”
In this near-perfect weekend, Aitken and Bamber led every session except the Saturday morning Practice 3 – which was a morning warm-up session in all but name.
Aitken leaves the weekend with a 144-point lead in the GTP drivers’ standings, and only four more races left for IMSA’s premier class. Bamber’s FIA WEC commitments leave him out of a share of the drivers’ title, but he was beaming with pride to reward everyone at Cadillac, Action Express, and all their partners with such a victory.
“When we’ve got such an amazing car, it makes it a lot easier,” Bamber said.
“But there’s also just a huge amount of work going on behind the scenes. The simulator work. The tyre correlation stuff we do with Michelin. And it’s paying dividends. I think we all spend – myself, like 60 days last year in the sim. When we can roll out on track and the car matches, we can do a lot of pre-work. And that shows at these sort of tracks.
“It’s all through the hard work. There’s so much work going on at the tech centre as well. We just get to execute on a weekend like this, and get the glory on the podium. But there’s a whole army of people that make it happen too.”
Detroit’s winners will soon pack their bags and travel eastward for the 24 Hours of Le Mans, where they’ll drive the #38 Cadillac Hertz Team JOTA entry alongside Sébastien Bourdais. On paper, it’s a trio that can be, and should be, considered among the favourites for the overall win at Le Mans.
And with the momentum on their side going into this year’s edition of the Grand Prix d’Endurance, there may be another special moment yet to come for Aitken and Bamber, the duo that’s been leading the charge for Cadillac this year.
Images © Jack Webster / dailysportscar.com
