By the time you read this the 2025 Season 4 Release Build is already live. Depending on how you feel about it, the new in‑Sim UI, rebuilt on a modern framework has already impressed or frustrated you! Although it might not look like much the changes bring a welcome update to the overall experience. There are however a few minor updates that you may have missed. Read to the end to see what these are in my opinion!
New content: cars and tracks
Three new cars join the fleet: Aston Martin Vantage GT3 EVO, Dallara IL‑15 (INDY NXT), and Ford Mustang GT4. The BMW M4 GT3 is updated to EVO spec with new physics and art. On the track side, Autódromo Hermanos Rodríguez (Mexico City) arrives with seven configurations, while Charlotte, North Wilkesboro, Sonoma, and World Wide Technology Raceway have been rescanned and remodelled.
I am personally quite excited about the addition of Sonoma and the Mexico City tracks. Both bring some unique characteristics that in the right cars should provide some great racing.
Physics & systems updates
Season 4 includes a multifaceted physics/tyre performance overhaul for the entire GT4 class, plus a hybrid system overhaul across hybrid car types. These changes are aimed at realism and consistency in how power units and class behaviour are modelled. I have not sampled either class of car but if the GT3 update is anything to go by I am quite keen to try GT4’s in the near future.
Rain readiness, AI, and dynamic track
All three new cars ship ready for rain racing. AI now supports the Aston Martin Vantage GT3 EVO, Ford Mustang GT4 and the NASCAR Gen4 cars, with AI retraining at multiple refreshed venues. The Dynamic Track Model also gets attention to better set initial conditions (weather/time effects) and align off‑track and on‑track surface temperatures. These are all changes that should further improve the immersion.
Beyond the rescans, several NASCAR‑schedule tracks and Oulton Park receive art overhauls. There’s also VR headset eye‑tracking / foveated rendering support listed among Season 4 highlights. This update is for those who, can turn laps in VR without needing a bucket next to their rig…
Patches and updates worth a second look
Patch 1 improved the overall UI by fixing some field of view calculations and allows for larger virtual mirror and delta bar options – something that bothered me when loading in after the initial update. Other updates such as expanded car setups, an auto fuel glitch, new spotter messages, updated visuals for damage etc. have all been made.
There were two general updates that I found quite interesting and might be worth looking into if you are a true iRacing nerd. Firstly, there have been very minor BoP updates to the likes of the Mustang, Mercedes GT and Porsche GT3 in the GT3 class. On the track front, track limits and slow down rules have been amended on selected tracks too. These updates may not be major, but worth a tenth or two to those that are chasing it!
Why this matters for your race week
Overall, the changes, once you get used to it, bring a welcome modernization to the aging UI and overall user experience. The car and track changes may or may not affect you depending on your preferred series. However, if you race in the classes where the recent changes where made, or like spending some ‘Randellas’ on the latest releases, the new content will be a welcome addition!
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