The iRacing 2026 Season 4 Release Build is moving out onto the track! This is one of four major annual releases for iRacing, and it adds new content, features, upgrades, and a hauler-full of fixes and tweaks. iRacing 2026 Season 4 officially starts on September 15th at 0000 UTC!
iRacing welcomes FOUR brand new cars into our garage, including the Aston Martin Valkyrie AMR-LMH, two versions of the Caterham - Academy and 420R, and the Gen 4 Grand National. A diverse set of vehicles showcasing the many ways drivers race! We’ve also added THREE entirely re-scanned and re-built tracks to update the iRacing 2026 landscape: Road America, Mid-Ohio Sports Car Course, and The Milwaukee Mile. Each of these tracks fully replace the older versions and are top-notch racing locations. Both Summit Point Raceway and Road Atlanta have also received a major artwork update, taking their appearance into the modern age. Finally, we plan to introduce a new system that more authentically replicates real-world multiclass race starts: dedicated pace cars for each car class. Please note that this feature must pass a final shakedown in Week 13’s iTested series before officially joining the IMSA iRacing Series.Our physics processing engine has been upgraded to allow for multi-threading, making object interactions more accurate than ever before. Car Rule Sets have been made available on dozens more vehicles, providing even more structure and options to the ways you can race. Our vehicle development team has completed a significant vehicle mechanics overhaul for both the Global Mazda MX-5 Cup and the Sprint Car - these cars should feel nearly brand new, and drive much closer to their real-life counterparts.The iRacing Simulation has been updated from stem to stern for complete UTF8 character support - this includes chat messages, display names, and all files associated with iRacing such as Replays, Setups, and Camera sets filenames. A new UI element has been added: Reference Car UI, which allows you to see live controls inputs from a reference car in solo sessions so you can learn and advance your own technique. TWO brand new UI Widgets are now available: Pit Summary which provides control and visibility to everything related to a pit stop, and Car Damage for a select few cars which displays the general health of your vehicle. The F9 Black Box has been reimagined as a Quick Access panel to add easy use for a variety of impactful options. A new UI Mode is also now available: “Minimal” where you can strip down your interface to only the essentials and anything else you’d like to keep pinned. Following up from last Season, the Fuel Calculator Widget algorithms have received more data and have improved estimates. The Track Map Widget has also been updated with some quality improvements for ease of use.The iRacing Launcher Team has completed a full rebuild of the Team Registration process, making it easier than ever to clearly see how your team is registered for an event, and what everyone is signed-up for. The Leagues area has been refreshed, leaving runway for upcoming improvements. Past Results may now be viewed as individual pages. When launching a solo session from an Official Session, you may now also carry in the BoP from the event to your test session, allowing you to practice better. The team also completed a re-build of the iRacing Companion App recently which will allow for even better future development - if you haven’t gotten the latest updates for it yet, be sure to grab them from your device’s preferred app store!Finally, AI racing has been expanded to EIGHT new cars, including: Aston Martin Valkyrie AMR-LMH, Caterham - Academy and 420R, Gen 4 Grand National, Chevrolet Corvette C7 Daytona Prototype, Formula Renault 2.0, [Legacy] BMW Z4 GT3, and [Legacy] Riley MkXX Daytona Prototype - 2008. AI racing is also now available at NINETEEN new track configs, including: Auto Club Speedway - Competition, Interior, and Moto, Federated Auto Parts Raceway at I-55, Kansas Speedway - Infield Road Course and Road Course, Mid-Ohio Sports Car Course - All configs, Oswego Speedway - Dirt, Road America - All configs, The Milwaukee Mile - Both configs, and USA International Speedway - Dirt. Rain racing availability comes pre-loaded with the new Aston Martin Valkyrie AMR-LMH and both Caterhams as well as all non-Oval new track configs.
Season highlights include:
Aston Martin Valkyrie AMR-LMH
Caterham - Academy and 420R
Gen 4 Grand National
Road America (Updated Laserscan & Fully Rebuilt)
Mid-Ohio Sports Car Course (Updated Laserscan & Fully Rebuilt)
The Milwaukee Mile (Updated Laserscan & Fully Rebuilt)
Summit Point Raceway (Major Art Update)
Road Atlanta (Major Art Update)
Multiple Pace Cars Multiclass Starts available in select official series, beginning with the IMSA iRacing Series
Multi-threaded Physics Processing
Full UTF8 character support
New SIM UI Widget: Pit Summary
New SIM UI Widget: Car Damage (Global Mazda MX-5 Cup, Toyota GR86, BMW M2 Racing (G87), Renault Clio R.S. V, Ray FF1600, Mini Stock, and Lucas Oil Off Road Pro 2 Truck)
New Sim UI Black Box: F9 Quick Access
Sim UI Update: Minimal/Pinned UI Mode
Sim UI Update: Fuel Calculator Widget improvement
Sim UI Update: Track Map updates
Global Mazda MX-5 Cup (significant vehicle update)
Sprint Car (significant vehicle update)
Car Rule Sets are now supported on 81 vehicles
iRacing Launcher Feature: Team Registration Refactor
iRacing Launcher Feature: Bring Official Session BoP into Test Drive
Rain racing for THREE more vehicles! (Aston Martin Valkyrie AMR-LMH, Caterham - Academy and 420R)
AI Racing is now available with EIGHT new cars: Aston Martin Valkyrie AMR-LMH, Caterham - Academy and 420R, Gen 4 Grand National, Chevrolet Corvette C7 Daytona Prototype, Formula Renault 2.0, [Legacy] BMW Z4 GT3, and [Legacy] Riley MkXX Daytona Prototype - 2008
AI Racing is available at NINETEEN new tracks: Auto Club Speedway - Competition, Interior, and Moto, Federated Auto Parts Raceway at I-55, Kansas Speedway - Infield Road Course and Road Course, Mid-Ohio Sports Car Course - All configs, Oswego Speedway - Dirt, Road America - All configs, The Milwaukee Mile - All configs, and USA International Speedway - Dirt
Hundreds of the highest quality vehicle setups
Visit our 2026 Season 4 features page here: https://www.iracing.com/seasons/2026-s4/
Full release notes can be found at: 2026 Season 4 Initial Release Notes [2026.09.09.01] — iRacing Forums