ChampCar sanctions a series of open wheel races descended from the Indy Cars of the 1990s, and also sanctions the ChampCar Atlantic support series.
In the late 70s, many of the team owners racing in the USAC championship series (aka Indy car racing) became concerned about USAC\'s management. Roger Penske and Pat Patrick led a breakaway group who founded Championship Auto Racing Teams (CART) in 1978. CART and USAC dueled for several years, eventually settling into an uneasy peace where USAC sanctioned the Indy 500 and CART sanctioned the remaining races. This relative peace lasted until the early 90s, when IMS president Tony George expressed public concerns about costs, shifts away from oval racing, and foreign drivers in the series.
In 1996, the Indy Racing League debuted, with the same cars and specifications as CART, under USAC sanction, and a full up sanctioning body war broke out. Both organizations staggered through the next several years, and the IRL debuted completely different cars and engines, rendering crossover difficult. A brief thaw in relations enabled temporary returns to the Indy 500 by Ganassi and then Penske in 2000 and 2001 respectively. After the Penske and Ganassi teams moved from CART to the IRL in 2002, many other CART teams followed suit, and CART went bankrupt. The organization was bought out by some of the remaining owners and renamed ChampCar. ChampCar has been gradually returning to health, and there is as of this writing (mid 2006) some talk of reunification with the IRL, although considerable uncertainty remains.
ChampCar Atlantic runs cars similar to the SCCA Formula Atlantic (originally Formula B in the 1960s). The series was originally sanctioned by SCCA Pro Racing with Toyota Engines, but shifted to CART/ChampCar sanction some years ago. The ChampCar series runs a spec version of the Atlantic with Mazda engines, whereas SCCA club rules still allow any homologated car that meets the requirements of the Formula Category Specification for Formula Atlantic.