patchSep 11, 2026
iRacing 2026 Season 4 Adds Four Cars, Three Rebuilt Tracks, and a Physics Overhaul
iRacing's 2026 Season 4 build arrives ahead of an official season start on September 15th at 0000 UTC, bringing one of the service's four annual content drops with it.
What changed
New cars:
- Aston Martin Valkyrie AMR-LMH
- Caterham Academy
- Caterham 420R
- Gen 4 Grand National
Rebuilt tracks (fully replacing older versions):
- Road America
- Mid-Ohio Sports Car Course
- The Milwaukee Mile
Major artwork updates to Summit Point Raceway and Road Atlanta.
Physics and mechanics:
- The physics processing engine has been upgraded to support multi-threading, described as making object interactions more accurate
- Significant vehicle mechanics overhauls for the Global Mazda MX-5 Cup and the Sprint Car, with both said to drive closer to their real-life counterparts
Features and systems:
- Car Rule Sets are now available on dozens more vehicles
- Full UTF-8 character support has been added across the simulation — covering chat, display names, replays, setups, and camera set filenames
- A new Reference Car UI element has been introduced (source text truncates before full detail)
- Dedicated pace cars per class, intended to replicate real-world multiclass race starts, are pending a shakedown in the Week 13 iTested series before joining the IMSA iRacing Series
For regular iRacing subscribers, the multi-threading physics upgrade and the twin MX-5/Sprint Car overhauls are the changes most likely to be felt immediately behind the wheel.