iRacing Season 2026 Season 4: four new cars, three rebuilt tracks

iRacing has released a major seasonal update marking the start of 2026 Season 4, introducing four new vehicles to the platform. The additions are the Aston Martin Valkyrie AMR-LMH, Caterham Seven Academy, Caterham Seven 420R, and NASCAR Gen 4 Grand National. The two Caterham models are sold as a single package.

Three circuits have been comprehensively rebuilt from laser scans: Road America, Mid-Ohio, and Milwaukee Mile. Road America now includes two additional short-course configurations, while Milwaukee Mile gains a road course layout threaded inside its oval banking.

The physics engine has undergone substantial revision for the Mazda MX-5 and Sprint Car, with updated tire models, suspension behaviour, aerodynamics, and related parameters. The underlying simulation code now runs multithreaded, reducing CPU load by more than 50 percent during dense traffic and large field sizes.

Additional features in the update include expanded AI racing modes, class-specific safety cars for multiclass events, and new on-screen widgets for damage display and pit-stop information.