Even people who find the whole NASCAR spectacle an inexplicable form of pseudo-entertainment, with its advertising billboards disguised as souped-up autos speeding in endless circles (the mind-numbing tedium interrupted only by bone-crushing crashes), will find this documentary a fascinating and touching look at the culture that breeds love of the car-racing game. The focus of “Racing Dreams” isn’t on the drivers who’ve made it but on youngsters who aim at eventually joining their ranks by excelling in the World Karting Association competition, in which they garner points in a series of races in which they drive specially-designed go-karts that can speed to some seventy miles per hour.

Marshall Curry, the director, has cannily chosen three very different competitors as emblematic of the entire field. One is Michigan lad Josh Hobson, a clean-cut twelve-year whose performance in school seems to be about as flawless as that on the track. He’s keenly aware of every aspect of the game, engaging in fund-raisers to help defray his family’s expenses and watching televised NASCAR events to see not just the races but how drivers act out of their cars. The second is Brandon Warren, a thirteen-year old kid with a feisty personality and deep southern drawl being raised by his grandparents; his mother’s absent and his father’s in and out of jail. He’s periodically accused of rough driving, which can disqualify you even if you win a race. Brandon also develops a nice friendship with the third kid, eleven-year old Annabeth Barnes, who comes from a racing family—her dad was a driver and her mother is an amusingly obsessed NASCAR fan—and aims to break the gender barrier in the sport.

The picture follows the progress of this trio through the five meets that make up the National Championship competition, with the ultimate winner determined by total number of points awarded for finishing placement in the races. And it shows us the standing of each contestant at the close of each step along the way. There’s some pretty exciting race footage, too.

But the meat of “Racing Dreams” is on the youngsters’ lives off the track. Will Josh’s parents mortgage the family’s financial future to bankroll his move from karts to cars? Will Annabeth keep racing, or succumb to the lure of pajama parties and the other joys of normal adolescence? Can Brandon control his temper, and will the presence of his dad, who again seems headed for a fall, so distract him that it ruins his chances? Curry (who also served as one of three editors alongside Matthew Hamachek and Mary Manhardt) cannily shuffles between the races and the kids’ home lives, using each to build suspense in the other.

Beginning with its three stars, this is a picture that’s filled with characters more interesting than those you’ll find in most fiction films. Even if you consider NASCAR itself a bore, you’ll find this snapshot of what’s often called its version of Little League compulsively watchable.