WSBT-TV reported the accident happened just before midnight Saturday at the New Paris Speedway, about 25 miles southeast of South Bend.
New Paris Emergency Medical Services Chief Rick Rolston told the South Bend station that debris from the crash flew into the stands, injuring six people.
The injured were taken to Indiana University Health Goshen Hospital. Officials said none of the injuries appeared to be life-threatening.
Investigators at the Elkhart County Sheriff's Department and officials at the track didn't return phone calls seeking comment Sunday.