Simplify the following text for a Grade 7 native English-speaking person.
Original: Cosworth designed a series of replacements for the DFS to be used in IndyCar and Champ Car racing : the X-series , beginning in 1992 with the XB .
Simplified: Cosworth needed to replace the DFS engines used in IndyCar and Champ Car racing . Cosworth designed the X-series , beginning in 1992 with the XB .