Nascar is low-tech in many ways. The car bodies must fit production sedan templates, so the the chassis is welded tubular steel instead of carbon monocoque like on F1 or Indycar. The engines are carbureted instead of fuel injected. There's no turbochargers (although Indy just got those back this year as well). There are strict rules about spoiler size and type.
They do make extensive use of sensors and telemetry, but the cars themselves are pretty retro.
They do make extensive use of sensors and telemetry, but the cars themselves are pretty retro.