Roughly 2 and a half hours into this year's Petit Le Mans, the #1 Cadillac was two laps down and looked, for all intents and purposes, to be out of the running for the overall win.
With the two Penske-run factory Porsches leading, Renger van der Zande was in amongst the LMP2 field, 16th overall. The Dutchman, in his final race with Cadillac after seven years with the American manufacturer, had only just climbed into the car, replacing Sebastien Bourdais, who had been in the pink Cadillac — pink for Breast Cancer Awareness Month — up until that point.
Bourdais had started the car fourth, but the race quickly went sour as the Cadillac team were pinged with a mechanical black flag from the stewards for overpowering. The team duly told Bourdais to come into the pits, where they plugged a laptop in and fixed what they thought was a faulty torque sensor.
This unscheduled 1:10 pit stop, 20 minutes into the race, cost them a lap. However, luck was on the American manufacturer's side: a full course caution had been called after the team came into the pits, meant they lost less time than they should have done, and they could immediately gain back the lap they lost.
At the restart, then, Bourdais sat 11th and last in class, but in a substantially better position than he'd have been in had the race not been temporarily neutralised.
In the next hour or so, he wasn't able to make much progress, getting up to ninth ahead of Andrea Caldarelli in the #63 Lamborghini SC63, plus Jordan Taylor in the #40 WTRAndretti Acura ARX-06, who'd just pitted from the lead.
The second full course caution was called for the large Andersen-Keating-Milner crash at turn 6. Every GTP, apart from J. Taylor, pitted, including Bourdais.
However, the sensor issue reared its head again. The team duly plugged the laptop back in, and as Chip Ganassi Racing team manager Mike O'Gara told IMSA Radio, they were just turning off sensors until they identified the faulty one.
This stop was longer, getting on for three minutes. Luckily the field was at a much-reduced pace, giving the engineers time to try and figure out the problem. Luckily, this time they fixed it — for good.
This left Bourdais, who had remained in the car, a lap down, not regaining it under safety car as he had done an hour previous. He remained in 20th, behind the LMP2s, for much of the next 40 minutes, only getting back to 11th when the LMP2 field pitted en-masse in green flag conditions.
He was, though, still a lap down. As The Racing Line's data analysis shows, his pace in the first two hours was not electrifyingly quick, having to pass for position multiple LMP2s and running in GTP traffic for almost all his two and half hours in the car.
Because the next pitstop was done under green, though, van der Zande exited the pits two laps down.
It didn't take the Dutchman too long to gain one of these laps back, as the overall leaders progressively made pitstops. However, with so few full course cautions — the race ran cleanly for three hours after a short yellow caused by an incident between two GTD cars — gaining that lap back was hard work.
With pace up amongst the fastest cars, usually in the top 5 fastest cars in the class in the second half of the race, the trio began to move up the order. Dixon, who replaced van der Zande in the car just after the four mark, sat seventh at the start of his stint, and by the end of his 2 hours in the car, had climbed up to fourth position.
Bourdais made his way into the podium positions when he climbed out of the car, to be replaced by van der Zande, with just over 2 hours left to run.
The Dutchman actually led a lap on lap 393, before pitting for the penultimate time and dropping to fifth.
However, he was still over a minute back from the leaders.
Time was rapidly running out to catch up and attempt to go for the win, in what was Chip Ganassi's final race with Cadillac, plus Sebastien Bourdais's last full-time IMSA race (at least for a while) before an expected switch to WEC with JOTA Cadillac, and van der Zande's final race with both Chip Ganassi and Cadillac before joining Meyer-Shank and Acura for 2025.
What they really needed was a full course yellow. Unusually for Petit Le Mans, the race had run under green flag conditions for the last 4 and a half hours, and while the team had got back onto the lead lap through sheer grit and determination — not to mention excellent pace and quick work in the pits — making up an entire minute in the remaining hour was a herculean task.
But then, a large crash at the top of the hill after the esses, involving the #55 Ford Mustang GT3 of Corey Lewis and the #120 Wright Motorsports Porsche 911 GT3R of Jan Heylen made it all possible again.
That wasn't all though. Lewis's car had hit the barriers hard and lost its front headlights, with the Mustang bouncing back on track facing oncoming traffic, while being totally unlit and after a blind crest. Terrifying isn't the word.
While most cars passing him avoided the Mustang, some by mere inches, Ricky Taylor in the second-placed #10 WTRAndretti Acura ARX-06 wasn't so lucky. He hit the Ford on drivers' left, wiping the left-hand side of the Acura out.
While R. Taylor did manage the return the chrome-blue Konica Minolta-sponsored car to the pits, it was clear immediately that it would be an instant retirement, with less than an hour left.
This, combined with fast work from the Chip Ganassi crew at the car's final stop, enabled van der Zande to advance up to second, behind leader Nick Tandy in the #6 Porsche.
The race restarted for the last time with 35 minutes to go. Tandy was defending well, but van der Zande used traffic to his advantage to pass the Brit into turn 1 with just 12 laps to go.
Tandy was then temporarily set back by #24 BMW's Philipp Eng's overly aggressive pass, putting the Briton briefly onto the grass,, he dropped valuable seconds giving van der Zande a small but workable buffer with less than 10 minutes remaining.
You'd think it was plain sailing from then, but no. The Cadillac's headlights had been faulty for a while, but one not working at various times. Up until that point, however, one had always stayed working.
With the time and laps remaining now both in single digits, all the beleaguered car had to do was make it to the flag. But then, disaster: both headlights flickered out, leaving the 38-year-old at the wheel in total darkness.
Fiddling around in the cockpit, van der Zande managed to get one headlight back on. From there, he just had to nurse the car to the finish, although in all the drama, Tandy had caught up. The gap at the line was just 2.9 seconds.
In the post-race press conference, the Dutchman explained what was happening in the car in those final few minutes.
"This manual we get from Cadillac is a lot of buttons and a lot of options," he said, "so I started to press all kinds of buttons this way, and it was still not good enough.
"Then it stuck more and more and more, then they told me press the white button. So I pressed the white button, and it worked. So we got the lights back."
As you can see from the graphs interspersed through this article, the #01 Cadillac was fastest in the last half of the race, as Bourdais, Dixon, and van der Zande pushed to catch the leaders.
They were slowest in the race's first quarter, when Bourdais had his issues with the torque sensor and had to pit twice to have it fixed. This meant he had to pass LMP2 cars for position, meaning he was around seven and a half tenths a lap slower than the leading car on pace in the first quarter, the #7 Porsche of Dane Cameron, Matt Campbell, and Felipe Nasr.
No doubt, though, they were helped by full course cautions, in particular the first full course caution, and the last. In the former's case, if they'd had to pit early to fix the faulty torque sensor in full green flag conditions, they'd have lost more time to their rivals in the GTP class, plus they wouldn't have gained back the lap they lost.
And, in the latter's case, this not only promoted them a position due to the #10 WTRAndretti Acura's retirement, but helped them close up the minute gap they had to Nick Tandy in the #6 Porsche.
But, that's the name of the game in IMSA: to use the inevitable cautions to your advantage. This, combined with the #01 Cadillac's pace in the second half of the race, made them the winners at Road Atlanta this year.
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