CITY OF INDUSTRY, Calif. -- Cedric Augustine, a 36-year-old maintenance worker and hip-hop fan, came to the Nextel Youth Speed Rally last Saturday for a free afternoon concert by Bow Wow and other rappers. But at the event, held at a go-cart track in this Los Angeles suburb, he was also inundated by various promotions for Nascar, the auto-racing organization of which Nextel Communications Inc. is the leading sponsor.

"I didn't know we had black race-car drivers," Mr. Augustine said after a brief onstage appearance by Bill Lester, the lone African-American driver on any of Nascar's three national racing circuits. Mr. Augustine says his interest in auto racing, which until now has been low, was piqued.

Hip-hop, the de facto soundtrack of contemporary urban youth culture, would appear to make an odd match with the 45-year-old National Association for Stock Car Auto Racing, with what is thought to be a predominantly white, heavily suburban and rural fan base. But although the contrast between the cultures of stock-car racing and hip-hop is particularly jarring, Nascar isn't alone in reaching out to more diverse audiences. The National Football League and National Hockey League have made similar efforts in recent years. Sports-industry observers have attributed these initiatives in part to the increasingly diverse population at large, aging of core baby-boomer fans and competition for younger fans' leisure dollars.

Nascar says it hasn't done its own demographic research that would spell out the characteristics of its fan base. But a survey conducted by ESPN last year found that African-Americans account for 9.2 percent of Nascar's 75 million fans, a share that Nascar and Nextel executives call unacceptably small.

The Youth Speed Rally, held the day before Nascar's Auto Club 500 stock-car race at the California Speedway in Fontana, is one of a series of efforts by the racing body to draw more minority fans, drivers and crew members.

Besides Bow Wow, the 17-year-old star of the show, the event featured appearances by actor and rapper Nick Cannon, who has appeared in movies like "Drumline," R&B singer Anthony Hamilton, and Wyclef Jean, former frontman of the hip-hop group the Fugees. Nearby, a 53-foot tractor-trailer was parked, where audience members could take a free spin in one of two $1.3 million Nascar racing simulators. "We're trying to grow our sport, like everybody else is," says Nascar Chief Operating Officer George Pyne. "This is an important initiative. We're in it for the long haul."

But in some parts of the African-American community, at least, the Nascar world has some explaining to do. There has been consternation about the widespread display of Confederate flags on fans' vehicles parked at races, and it isn't hard to find unauthorized merchandise on the Internet that combines images from Confederate flags and Nascar racers.

A Nascar spokesman says the racing body recognizes the display of Confederate flags as "a sensitive issue for everybody" and adds: "You will not find the flag on anything that Nascar controls or licenses."

Last November, according to the Miami Herald, a group called the National Association for Minority Race Fans, staged a protest outside the Ford 400 race in Homestead, Fla., at which they offered a free American flag to any fan who turned in a Confederate flag.

A Nascar spokesman dismisses that protest and others that the group staged last fall as thinly veiled efforts to extort money from the racing body. The protest group's Web site includes a page encouraging visitors to join a class action against Nascar. Representatives for the Association for Minority Race Fans did not return calls for comment.

Nascar itself has undertaken efforts such as "Drive for Diversity," a program that seeks to cultivate minority drivers on its lower-profile, regional racing circuits. Its executives have also gone on a recruiting tour of historically black colleges, seeking future executives. The organization has enlisted Earvin "Magic" Johnson, the former Los Angeles Lakers basketball star, to serve as co-chairman of its "executive committee on diversity."

On Sunday, the day after the Bow Wow concert, Nextel arranged to transport 100 mostly African-American youths about 65 miles from Los Angeles to Fontana to watch the Auto Club 500 race. The young people were treated to behind-the-scenes tours, driver meetings and other special touches _ "the same experience we give VIP customers," says Michael Robichaud, senior director of sports and entertainment marketing at Nextel.

To attract a young, urban audience to the Youth Speed Rally, Nascar publicized the event heavily on a local hip-hop radio station, whose on-air personalities hosted the event. It also promoted the rally at several inner-city Starbucks franchises owned by Mr. Johnson, as well as through his chain of eponymous movie theaters. (Asked how much all this is costing, a spokesman said, "I don't know that you could put a dollar figure on it.")

The youth rally was organized by Michael Mauldin, who handles the career of Bow Wow, and runs a marketing company that uses hip-hop to connect national brands with urban consumers. Last year, he staged a similar event, "Welcome to Atlanta Nascar Weekend," which also featured Bow Wow, as well as the hip-hop producer and artist Jermaine Dupri, who is Mr. Mauldin's son.

Also last year, Mr. Lester's racing-tuned pickup truck featured the cover artwork from a CD by the hip-hop group N.E.R.D. emblazoned on its hood by one of the driver's primary sponsors, a music-marketing company. The company, LidRock, makes miniature promotional CDs that are packed within specially made soft-drink container covers.

Bow Wow, known until recently as Lil' Bow Wow, says he first attended a Nascar race after Mr. Mauldin proposed the promotion. He says he found the experience "something new, something fresh. It was like an adrenaline rush." He says he has since been to three more races and become friendly with Nascar driver Brian Vickers, a music enthusiast who has appeared on MTV's show "TRL."

"We've discussed doing some things with his race car," says Bow Wow.

A spokesman for Mr. Vickers says there has been discussion of a possible one-shot, full-car "paint scheme" promoting an upcoming Bow Wow album, although nothing has been nailed down. Such a placement could cost as much as $500,000.

Mr. Mauldin insists Nascar is a natural fit for African-American fans, who, he says, "love automobiles and speed." The main reason he believes African-Americans have not shown greater interest in Nascar so far: "They haven't been formally introduced."

But a mere introduction may not be enough of a push for everyone. At Saturday afternoon's Youth Speed Rally, the people in front of the outdoor stage appeared much more interested in a free rap concert than in exploring Nascar.

At one point midway through the event, while DJs blared music and fans waited for Bow Wow to appear, there were only four people inside the truck carrying the racing simulators: All were members of a white family who said they had come to the go-cart track for a birthday party, unaware that there was a hip-hop concert scheduled for the same day.