Brandon Gieseke figured it out pretty quickly.

This was no Wisconsin Dells.

Gieseke was picked to drive the first leg of his team’s first heat in the third-annual MRCI Foundation Grand Prix Saturday afternoon, and he thought it would be like any other go-kart driving he’s done.

“It was harder than I expected,” said Gieseke, driving for the Unicel team. “I was talking trash, and saying, ‘I’ll be fine.’ But, on that first corner, I literally spun all the way around.”

When the green flag drops, the event isn’t at all like a family-vacation fun stop.

The racers are serious, the cars are fast and there’s plenty of bumping, passing and other jockeying for position.

“It’s 100 percent different,” Gieseke said. “They go a heck of a lot faster. ... When you take a corner, you have to brake.”

One of Gieseke’s teammates, Michelle Welckle, found out the hard way. She got bumped, slid out around on a hairpin turn and allowed just enough space for her nearest competition to slip between her kart and the two-foot-high plastic wall.

“It hurts,” Welckle said of the bumper-to-bumper action, “especially when your helmet’s too big.”

Unlike Gieseke, Welckle got some practice laps in on Friday evening. But the morning rain, which delayed the start of the racing and canceled the celebrity race — rain also delayed racing in the late afternoon — changed the conditions a bit.

“The track was faster than last night,” she said. “You spun and slid around the corners a lot more. It was tough.”

In all, 52 teams and 260 drivers participated in the Grand Prix, which has become the MRCI Foundation’s signature fundraiser.

According to foundation director Jennifer Hlubek, the event grossed $25,000 last year, with $17,000 going to support MRCI’s worker transportation program, which gets people with disabilities to jobs every day.

“This fundraiser is for them,” she said.

This year, Hlubek said, races are expected to bring in $30,000 in sponsorships and team fees.