Marc Davis was doing what Nascar drivers do all the time—getting even.

With 10 laps to go in a tight 200-lap race at Hickory Motor Speedway, Davis, then 16 years old, was fighting hard for the win when a rival tapped his rear bumper and sped around him as he tried to recover. On the next lap, Davis repaid the favor by thumping his competitor and causing him to spin out. Both ended up at the back of the pack. For the drivers, this was no big deal. Retaliation is part of the sideshow that gives Nascar its edge. But this episode had an extra element: Davis is black, and his rival, also a teenager, was white. (View slideshow.)

And Hickory, 50 miles northwest of Charlotte, North Carolina, is Nascar bedrock, America’s oldest continuously operating motor speedway and the hallowed minor-league track where such legends as Dale Earnhardt and Richard Petty cut their teeth. It attracts a hardcore following, an overwhelmingly white crowd that was perfectly happy when Nascar was just a backwater redneck sport. So though Davis had already proved his Nascar mettle by winning six races at Hickory that year, his tangling with a white driver caused an uproar among about a hundred fans, who stormed a fence surrounding the track, some of them chanting, “Go home, nigger!” Several were ejected from the stands.

As for Davis? He walked away like a driver from a bad crash, determined not to let the episode dampen his ambition to become one of the best drivers in the history of America’s second-most-watched sport. He had already inked a six-year deal with Joe Gibbs Racing, the powerhouse established by the famed Redskins head coach and run by his son J.D., and home to Nextel Cup Series contenders Tony Stewart and Denny Hamlin. By the 2007 season, Davis had graduated from the Hickory farm club to the Busch East Series, an East Coast racing circuit known for developing young racers, and finished in the top 10 among more than 70 drivers. When he turns 18 this June, Davis, a daredevil since his elementary-school years, is expected to climb yet one more Nascar rung, bringing him closer to his goal of racing against the likes of Jeff Gordon and Jimmie Johnson. Of the racial incident, Davis’ father and manager, Harry, says, “It is what it is, but I will not allow it to be a roadblock. Our only purpose is to race.”

Nonetheless, the 2006 Hickory dustup reinforced the perception that, for all of its money, clout, and visibility, Nascar remains an intolerant backwoods sport. The incident called attention to what is perhaps the worst-kept secret in the business: America’s top racing franchise, with more than $380 million in revenue and a combined live and TV fan base of about 75 million, has a race problem. In the 60 years since Big Bill France founded Nascar in Daytona Beach, Florida, only three black drivers have ever competed in a top-tier race, and only one—Wendell Scott—has ever won one. The number of blacks driving in the three major Nascar series these days fluctuates between zero and one. Forty-five years after Scott’s victory, Nascar is still searching for its Jackie Robinson (or its Tiger Woods).

But lately, that quest has become more imperative, for after two decades of supercharged growth, huge attendance, and stunningly lucrative corporate sponsorships and TV deals, the oval-track racing circuit has hit a rough patch. Race-day seats are going unsold, and TV ratings are flat or falling—a development that factored into NBC’s decision to pull out at the end of the 2006 season after having broadcast races since 2001. (The contract has since been picked up by ABC and ESPN.)

The job of reversing these trends has fallen to Brian France, Big Bill’s 45-year-old grandson and the son of Bill France Jr. Though he officially took over as Nascar’s C.E.O. only four years ago, France is known as a business progressive and is widely credited for some of Nascar’s best growth years. For example, France—sometimes over the objections of Nascar’s fans, drivers, and owners—moved races out of various Southern boondocks and into big media markets like Chicago, Los Angeles, and Las Vegas, all in the name of increasing Nascar’s visibility. For a publicity gimmick in November, he had Nascar racers zoom down Broadway through New York’s Times Square.

Now, having wrung the easy growth out of moves to urbanize the circuit, France is convinced that Nascar can continue to grow only if it broadens its minority fan base, which sits stalled at about 18 percent of its audience and is divided equally between blacks and Hispanics. In his state-of-the-sport address given at the beginning of the 2007 racing season, France spoke openly about the need for change. “I remain not only committed but convinced that if we don’t get diversity right, this sport will not achieve what it needs from a popularity standpoint, won’t get the best drivers, won’t get the best talent on the management side, won’t get the fan base that we deserve,” he told reporters. He later admitted there’s a tricky part to this: How does Nascar attract a more diverse audience without alienating those good-old-boy fans? Or put another way: Could doing the right thing turn out all wrong for Nascar’s growth plans?

Marc Davis may one day break out as a top-ranked, lucratively sponsored black driver, but the story of 46-year-old Bill Lester is probably more illustrative of the challenges black drivers have faced during the past decade. For several years, Lester drove in the third-tier Craftsman Truck Series (Nascar’s tiers aren’t all that different from Major League Baseball’s farm club system) and was the only minority driver competing full-time in Nascar. When he made his Nextel Cup debut at Atlanta Motor Speedway in 2006, he was the first black driver to reach Nascar’s highest rung in 20 years. As the 2007 season got under way, team owner Billy Ballew announced plans to enter Lester in at least four Nextel Cup races. By the end of the season, however, Lester not only hadn’t competed in a race, but his career at even the Craftsman level was essentially over. Though Nascar boasts 106 Fortune 500 companies as sponsors, Lester was unable to secure a financial backer, Fortune 500 or otherwise, and ended up sidelined in mid-August with 10 races to go.

One African American with a bird’s-eye view of Nascar and extensive knowledge of its diversity efforts is former N.B.A. star Brad Daugherty, who once owned a Nascar Craftsman Truck Series and Busch Series team and now provides commentary on Nascar races for ESPN. Daugherty, who got hooked on the races while growing up in North Carolina, says the sport’s overwhelmingly white, Southern fan base makes many corporate sponsors reluctant to put their money behind a black driver for fear of a fan backlash against their products. “I had trouble with the corporate people, because they wanted to dictate who was on my race team and who I put in that truck,” Daugherty says of his efforts to sign up a black driver. “If you’re going to put an African American or a face of color in your truck, your corporate sponsors have to agree,” he says. “I’ve sat in meetings with Fortune 500 companies that are interested in helping me put together a program, but at the end of the day, all they want to know is ‘How does Nascar feel about it?’ ”

It’s clear how Brian France feels about it, and he can point to some recent success in making Nascar less homogeneous at the corporate level. Nascar’s managing director of public affairs, Marcus Jadotte, is black, as is Max Siegel, a former Sony BMG executive who was named president of global operations for Dale Earnhardt Inc. in 2007. Indeed, France can say that the percentage of blacks in the Nascar executive suite—about 15 percent—is almost double the proportion of its black fan base.

But so far, the commitment to change at the executive level hasn’t translated into diversity behind the wheel. Beginning in 2004, Nascar formally confronted the issue by launching Drive for Diversity, a program designed to produce elite minority and female drivers by providing financial support from sponsors including Sunoco, Domino’s Pizza, and Eastman Kodak. Each fall for the past four years, prospective drivers have gathered in South Boston, Virginia, to race in front of Nascar recruiters at a scouting combine in the hope of securing a contract with an established team. Nascar officials even brought in Magic Johnson to serve on a committee to help create programs that would find and develop black, Hispanic, and female drivers and crew members.

To date, though, Drive for Diversity has produced little in the way of results. A few drivers have been selected to compete in low-level circuits and development series, but not a single program participant has yet competed full-time in a Nascar series. Supporting a driver full-time in the development series can cost more than $750,000. The $150,000 in sponsorship funds that Drive for Diversity offers participating teams comes nowhere near to covering that. People with knowledge of Drive for Diversity will say on the record that it’s a decent effort, albeit a work in progress. Off the record, most call it a sham—an underfunded shillfest that has killed more careers than it has made, angering whites while alienating the very minorities it’s meant to encourage. Tommy Gray, a Concord, North Carolina, teacher and mechanic who has worked on Drive for Diversity teams, says that in far too many cases, the program’s money was diverted to cover overhead and never reached the drivers. “There were several programs that never spent the money on the cars or on the team,” he says.

And as for Magic Johnson, years after his much-heralded appointment, he is largely a Nascar no-show. (Johnson didn’t respond to emails and phone calls seeking comment.)

Drive for Diversity touts Marc Davis among its successes, but Davis left the program after just one year, when his school schedule didn’t permit him to attend the 2006 scouting combine. (And Chase Austin, another rising young black driver, declined even to participate in the program.) In fact, Davis’ route to the brink of Nascar’s big leagues is largely the result of the diversity efforts of the Joe Gibbs Racing team and the Davis family’s commitment to do whatever is necessary to nurture his passion for racing. “When I call him my million-dollar baby, it’s not because that’s what he earns. It’s because that’s how much we’ve spent on his career,” says his father, who previously worked in Washington, D.C., as a network-news cameraman.

Davis drove his first racecar at age seven, moved to the Junior Dragsters program in the National Hot Rod Association, and competed for three years in the Bandolero series, a nationwide circuit that invites kids as young as eight to race in standardized souped-up go-carts. By the time he turned 13, Davis raced almost every weekend, traveling 15 hours each way from Maryland to Florida for a 25-lap competition. The efforts paid off with two national championships in the Legends series (contests using smaller replicas of 1930s-style street racers). “That was an amazing season, one of those seasons you might never have again,” Davis recalls.

After Davis’ father retired in 2005, he and Marc left family and friends behind and relocated to Mooresville, North Carolina, where many of the Nascar teams have their headquarters—a move they considered a necessary sacrifice to reach the next level. While Davis was establishing himself as one of the best young drivers in the country, Joe Gibbs Racing was searching for a way to recruit more minorities. Years before Siegel became president of Dale Earnhardt Inc., he and a friend, N.F.L. Hall of Famer Reggie White, wanted to start a Nextel Cup team with a minority driver. Because of the prohibitively high costs and the challenge of finding sponsors for an untested team, their plans never materialized. Ultimately, White formed an alliance with Joe Gibbs Racing and started its diversity program, which held its first scouting combine in 2003. After White’s untimely death from cardiac arrhythmia in December 2004, J.D. Gibbs, Joe Gibbs Racing’s president, forged ahead with the program, though he doesn’t harbor any illusions of finding a quick fix for Nascar’s diversity problem. Bringing up a young driver “is so expensive, no matter what your background,” Gibbs says. “The diversity side just takes time. You’ve got to find some young guys and train them.”

It was while racing almost every weekend at Hickory that Davis, 15 at the time, first came to Gibbs’ attention. “Our guys saw him and said, ‘He doesn’t have much in the way of equipment, but he’s running really well with what he’s got. We’d better keep an eye on him,’ ” Gibbs recalls. Davis’ performance earned him a six-year contract. But getting a ride with an established team is easier than finding sponsors, especially when race is added to the mix. For Nascar’s three top-tier series—Craftsman, Nationwide (formerly Busch), and Sprint Cup, as the Nextel Cup will be called in the 2008 season—the single-season price tag for sponsors is roughly $4 million, $8 million, and $20 million, respectively, to cover the cost of multiple cars, drivers’ salaries, and pit crews. (Sponsors pay more for exposure in the huge, nationally televised races like the Nextel Cup Series.)

Gibbs doesn’t view the difficulty in lining up sponsors as a strictly racial matter but rather one of corporate priorities. Compared with the Nationwide and Nextel series, Craftsman draws far fewer spectators, and Nascar’s rookie-development series attracts an even smaller number of fans. Corporations are understandably reluctant to fork over hundreds of thousands of dollars for so little exposure. Gibbs notes that he’s had no better luck getting a sponsor for racing phenom Joey Logano, whom he signed around the same time as Davis. At 17, Logano, a white Connecticut native, was the youngest driver ever to win the Busch East Series. Yet despite Logano’s record, Gibbs couldn’t secure backing for him and ended up sponsoring both him and Davis on his own. “Everybody wants to be a part of something new, different, and great. I think once Marc gets some momentum and makes a name for himself, we’ll get the sponsors for him,” Gibbs says.

Nascar’s efforts to reel in Hispanic fans seem to be faring somewhat better, in part because Indianapolis 500 champ Juan Pablo Montoya defected from Formula One to the circuit. Before a 2007 race at California Speedway, in suburban Los Angeles, racetrack officials covered bodegas and cafés with Montoya posters and hung advertisements on thousands of doors in Hispanic neighborhoods. All displayed a toll-free number that, when called, played an invitation to the race from Montoya in Spanish. Similarly, when Montoya raced at the Homestead-Miami Speedway, in Florida, Nascar set up a special Montoya-rooting section in the grandstand.

Still, even successful efforts like these can stir a backlash. The trend of foreign drivers defecting to Nascar has drawn a rash of angry letters to Nascar Scene, a weekly fan publication. “On the subject of foreign drivers, enough is enough,” one reader wrote recently. “We want American drivers with the names of Americans. Let the foreigners drive in Europe and Formula One.”

Without a prominent black driver, Nascar has had an even harder time attracting black fans, which is why J.D. Gibbs and Nascar officials have high hopes for Davis. But Davis himself is unflustered by the attention. His day-to-day life is a lot like that of any other high-school kid and race junkie: classes at the Mooresville Christian Academy from 8 a.m. to 2 p.m. followed by a mandatory workout session with his personal trainer at the Gibbs race shop from 3 p.m. to 5 p.m. He spends most evenings with friends, customizing, painting, and rebuilding his growing collection of souped-up cars. Davis is accustomed to being asked this question: Why would a black kid from Maryland focus on Nascar, some of whose fans wave Confederate flags from R.V.’s in the infield on race day and become infuriated at the sight of Toyotas and even white foreign-born drivers participating?

Davis shrugs. He’s not racing as a “black driver.” What drew him to the sport—the speed, his competitive nature—is what keeps him there. Moreover, Nascar is the best fit for his ambitions. “I used to do a lot of road-course racing, but I was always a little bit better at oval tracks,” he says.

If Davis happens to become a black role model, so be it. “But I never really thought about the racial things,” he says. “I race because I love it.”