Draft:CART–IRL split

The CART-IRL split refers to the split within the top series of open wheel racing in the United States, known as Indy car racing between the Indy Racing League (IRL) and Championship Auto Racing Teams (CART), two sanctioning bodies over the top level of American open-wheel racing. The split was over the costs related to compete and the focus on ovals. In 1994, the IRL was founded as an oval-forward Indy car series to start in 1996 by then Indianapolis Motor Speedway owner Tony George. Before the founding of the IRL, top-tier American open wheel racing was unified under the CART sanctioning body from the 1980s after the CART–USAC split.

The split led to a period from 1996–1999 where no CART teams ran at the Indianapolis 500, which was sanctioned by the IRL after taking over from USAC in 1998, including an attempt at a direct competitor to the Indianapolis 500 in 1996, with the running of the 1996 U.S. 500 in Michigan on the same day as that year's Indianapolis 500. The split continued until 2008, when the Champ Car World Series, the successor to CART from 2004 onward, folded after the 2008 Grand Prix of Long Beach; This left the IRL, renamed to IndyCar Series in 2003, as the only remaining series.

USAC-CART split
In 1979, there was a split between CART and the United States Auto Club (USAC), resulting in the second major split in American open wheel racing. After dissatisfaction with the way USAC operated, Dan Gurney, along with other racing team owners, founded a competing organization that also ran Indy cars, and this was called Championship Auto Racing Teams, which was shortened to CART. This split led to acrimony initially, with USAC refusing to allow CART cars to compete in the Indianapolis 500, the most notable race in American open wheel racing, for the 1979 edition of the event. This attempted ban on CART cars did not come to fruition, as a court order required that USAC allow for CART cars to enter, stating that USAC's position was in violation of antitrust laws. In 1980, the two had attempted to reunify under the Championship Racing League, which lasted for five races in the 1980 season, until the CART–USAC agreement fell apart. After this season, CART went on to gain much more prominence, and by 1985 USAC's only sanctioned top level open wheel race was the Indianapolis 500.

CART-IRL split beginnings (1994–2000)
While CART had become the premiere organization for American open-wheel racing; there grew growing discontent with how CART was run from the management of the Indianapolis Motor Speedway, with Tony George complaining of being regularly shut out from having any input into CART. CART, for its part, had placed Tony George on their board; however, as a non-voting member, and it has been reported that many of George's suggestions to the CART board were rejected. With the conflict between Tony George and CART management reaching a boiling point in 1994, George announced the creation of a new racing league called the Indy Racing League (IRL), which began racing in 1996. In July 1995, months before the IRL had started racing, the IRL sent out a PR document that 25 of the 33 seats at the 1996 Indianapolis 500 and all Indianapolis 500 races going forwards, would be reserved for cars in the IRL; this is generally known as the 25-8 rule. This broke with tradition of the Indianapolis 500, where traditionally, regardless of what series a car ran, as long as a car within the specifications qualified within the top 33, that the car could race. CART responded to this by announcing a race of its own, the 1996 U.S. 500 at Michigan International Speedway on the same day as the 1996 Indianapolis 500, effectively leading to a CART boycott of the Indianapolis 500. This boycott continued into 1997, where CART ran a race the 1997 Motorola 300 at Gateway Motorsports Park in suburban St. Louis the day before the Indianapolis 500. The IRL withdrew the 25-8 rule after the 1997 Indianapolis 500; however, this did not bring back any CART teams for the 1998 Indianapolis 500, with no CART teams entering the Indianapolis 500 until Chip Ganassi Racing entered cars in the 2000 Indianapolis 500.

Beginning of CART's demise (2001–2004)
After the Ganassi Racing cars entered in the 2000 Indianapolis 500, Team Penske entered three further cars for the 2001 Indianapolis 500 with 6 total CART drivers – Michael Andretti, Gil de Ferran, Hélio Castroneves, Jimmy Vasser, Bruno Junqueira, and Nicolas Minassian – slated to participate in the race. Following this, for the 2002 Indy Racing League, Team Penske moved to the IRL from CART. While in 2002, Ganassi Racing had three cars in CART, there was also one entry from the team in the IRL that season, and in September of 2002, annouced it would only run in the 2003 IndyCar Series (renamed from the Indy Racing League) and would not be running any more cars in CART moving forward. CART's woes continued through the 2003 CART season, hitting a nadir with the 2003 Grand Prix of Long Beach having more race-day attendees than television viewers. Furthermore, the 2003 season saw three engine manufacturers entering cars into the IRL, with only one engine manufacturer providing engines for CART's 2003 season. Furthermore, two teams made a transition from CART to IRL for the 2003 season with Andretti Green Racing makinga full time debuts with multiple cars. Also, Team Rahal and Fernández Racing both entered one car into CART and one car into IRL for the 2003 season, with both teams having all of their cars in the IRL for the begininng of the 2004 IndyCar season.