A team of engineers and two crazy drivers are preparing for a history-making challenge drawn from the daydreams of every child who's ever crisscrossed his parents' living room with plastic race tracks: building, and racing on, a human-scale Hot Wheels double loop track, just like the one you had when you were a kid.

The "Hot Wheels Double Loop Dare" is set to take place at this month's Summer X-Games in Los Angeles. Drivers Tanner Foust and Greg Tracy will attempt to race through a 60-foot vertical loop modeled after the new Double Dare Snare Hot Wheels toy, in what would be the first time in history two cars mounted a vertical loop at once.

"We’ve done large-scale stuff before,"said Dave McKay, of Laissez Faire, the company that designed and created the physical structure for the stunt."But this is the biggest stunt that I've ever been apart of."

It's a race and a stunt in one, with the drivers racing two purpose-built cars at 52 mph down separate tracks that merge into one big loop, where they will face a a gravitational force of 7 G's (that's what a fighter pilot feels), before being spit out on the other side to complete a jump. First one through wins.

The real double loop track next to it's toy version. Photo: Lindsey Boice, courtesy Mattel LINDSEY BOICE

Not that these drivers aren't skilled in their craziness. Foust is a pro Rally and Drift driver, with 3 X-Games Gold Medals and two Formula Drift championships under his belt, and he broke the world record for the largest leap by a four-wheeled vehicle in another stunt for the Hot Wheels team last year. Tracy is a professional stunt driver featured in both movies and television, and is a six-time Pikes Peak Champion – an extreme racing event.

To prepare for the new stunt, Foust and Tracy underwent flight training in Northern California, where they were put on a plane rated at 10 G's. "This particular stunt, it is a different mindset, the physical undertaking is tremendous," said Foust in an interview during training.

Plans and preparation have been underway since last fall, where former NASA lab experts, roller coaster engineers and stuntmen came together to concoct the life-sized track. In the end, and after what Foust calls a "mind boggling amount of physics," the 700-foot long (about two football fields) track and 125 tons of steel loop were complete.

The physics of circular motion, though mind boggling, is what makes both the toy and its counterpart work. "When you drive through the loop and you turn towards the center and there’s an outward force," explains McKay, "We design the car, track and training the drivers to handle the 7G's of force.”

A stunt like this has to be calculated perfectly. Drive too slow, and you fall out; drive too fast and the G force become dangerous to the drivers. So the engineers modeled every scenario and came up with the optimal range of speed to make it safely through the loop.

This sort of modelling, understanding the physics of the structure, and having the correct speed, are the best safety precautions one can take, said McKay. They leave no guesswork. However, the team of engineers took other safety precautions on the vehicle, structure and drivers, designing a car that fits the radius of the loop that has no drag, nets on the loop during training, and NASCAR-issue roll-cages, neck braces and harnesses for the drivers.

The event will take place in downtown Los Angeles on June 30. "The structure itself is just beautiful," said McKay. "It's going to be really exciting."