Van der Zande was involved in a dramatic moment just before sunrise, as his Chip Ganassi Racing Cadillac clashed with the Action Express example of Kamui Kobayashi, which caused the latter to spin at Turn 1.
The Dutchman also reported that lapped traffic was causing huge problems for the front runners, as the race builds towards its finish.
“There’s some crazy stuff going on out there, I can tell you that,” van der Zande told NBCSN. “Sometimes with the LMP3 cars, they drive right in the middle.
“Basically that means you have to drive with two wheels in the grass to get by them. That makes it exciting out there. And all these drivers are half asleep by now! I think that’s the case as well.”
The #01 Ganassi car picked up pace on Sunday morning, and a nose change gave it a better balance.
“[It] worked out well, after that I found some extra pace, so it was a good change – a couple of tenths maybe, that’s it,” added van der Zande. “That makes a difference.”
The race is developing into a battle between his car and the #10 Wayne Taylor Racing Acura – the team that van der Zande switched from in the off season.
“Seems like some cars are running quicker today than yesterday, but it’s OK, we’re going OK,” he said. “We’re tuning up the balance here and there to make it better. Still a long way to go, so keep it tight, keep it clean. No mistakes is the key here.”