iRacing’s Season 4 2025 build is set to release next week, bringing three new cars, one new track, a new UI and several other new features.
iRacing’s Season 4 2025 build is nearly upon us, and the sim’s Senior Vice President and Executive Producer, Greg Hill, has previewed several new features and pieces of content we can expect to see before the end of the month.
Fans can expect at least three new cars, one new track, multiple circuit refreshes and a whole new user interface when the build is expected to drop next week. Check out all the details below.
Car updates
New cars
- Aston Martin Vantage EVO GT3
- Dallara IL-15, Indy NXT
- Ford Mustang GT4
Aston Martin Vantage EVO GT3
The Aston Martin is the Gaydon manufacturer’s latest GT3 challenger, featuring a completely overhauled aero platform and tuning from Aston’s motorsport wing, AMR. iRacing intriguingly states this represents the beginning of a wider deal with Aston Martin for more collaboration in future, raising the chances of seeing the wild Valkyrie Hypercar in a future update.
Dallara IL-15
The Dallara IL-15 is the weapon of choice for the INDY NXT series, the main feeder category for INDYCAR. Its two-litre turbocharged engine produces 450 bhp, and it will be presented as a Class C runner in both road and oval series going forward.
The cars will also have a push-to-pass system that delivers an extra 50 bhp.
Ford Mustang GT4
The Ford Mustang takes its bow in iRacing’s GT4 class, boosting its numbers to seven (if you include both BMW M4s).
Powered by a suitably raucous five-litre V8, the Mustang was co-produced by Ford Performance and Multimatic, the Canadian motorsport specialist that also builds chassis for the Porsche 963 Hypercar.
GT4 class physics update
Much like the revised GT3 physics introduced in June, the platform’s GT4 cars have been given a significant update based on the real-world IMSA Michelin Pilot Challenge Series ruleset.
‘Top speeds will be higher and minimum corner speeds lower’, according to Hill’s recent dev blog, with tyre warmer temperatures decreased. This means players need to take care on their outlaps on colder rubber.
The main updated features of the GT4 physics update are as follows:
- TC, ABS, and ESC systems (where appropriate)
- Dampers for improved body control, particularly for curb strikes and rough tracks
- Engine torque curves
- Brake systems (particularly brake pads)
- Mass, inertia, and distribution properties
- Aerodynamic factors, particularly dynamic side force, wing trim ranges, and ride height ranges
- Fuel tank size, fill times, and fuel burn rates (standardised to smaller IMSA Michelin Pilot Challenge Series ruleset)
- BoP to improve relative competitiveness across track types for all cars
- Other QoL items include low fuel warning clear buttons, finer adjustment of spring perch offset, improved garage tech tips, and layouts.
BMW M4 GT3 gets Evo upgrade
iRacing’s BMW M4 GT3 is to get its real-world Evo upgrade, including new headlights, taillights and revised aerodynamics. The update is free for owners of the current M4 GT3, which has now been superseded and replaced.
Six out of the sim’s 10 GT3 cars will also receive gear ratio updates in line with their current Balance of Performance (BoP) calculation.
Tracks
New track
- Autódromo Hermanos Rodríguez – Mexico City
Autódromo Hermanos Rodríguez is used in both Formula 1 and NASCAR, making the Mexico City-based circuit a popular inclusion in iRacing.
The track will arrive with seven different configurations, with the location’s high-altitude simulated to allow higher top speeds at the expense of less downforce.
General track refreshes
Oulton Park receives a free spruce-up, with all its textures either remodelled or retextured to 2025 levels.
Final NASCAR track refreshes and rescans
The NASCAR Refresh project sees its final update in build 4, with five track refreshes and five complete rescans taking place.
Rescans include Sonoma Raceway and Charlotte Motor Speedway, while Watkins Glen and COTA receive 2025 updates to their kerbing, allowing players to unleash their inner Shane Van Gisbergen.
All of the NASCAR Refresh project is available free to iRacers who already own the required content.
Refreshes
- Daytona International Speedway
- Circuit of the Americas (now featuring the 2025 NASCAR config)
- Watkins Glen International (now featuring 2025 bus stop curbing)
- Chicago Street Course
- Texas Motor Speedway
Rescans
- World Wide Technology Raceway
- Charlotte Motor Speedway (partial Roval rescan)
- North Wilkesboro Speedway
- Sonoma Raceway
- Rockingham Speedway (may arrive in post-release patch)
New UI
iRacing’s UI has been a bugbear of many sim racers, thanks to its occasionally cluttered and confusing design.
However, with the onset of the Season 4 2025 build, iRacing has managed to tidy up much of its menus and functions, making it easier to navigate the sim’s myriad options and settings.
Check out the main improvements as detailed by iRacing below:
- Tooltips: The vast majority of controls now display tooltips when you mouse over them.
- Sim Options redesign: Options have had a significant reorganisation, including the merging of the Replay and Driving graphics options. We’ve also added a clickable table of contents down the left-hand side, and to the right, we’ve added more information to explain the setting.
- Alt-K to move UI: When pressing Alt-K to move elements around, you’ll find an additional toggle control to enable/disable all moveable elements, so now it’s easier to visualise those elements which normally only display when activated (such as flags and penalty notices).
- Virtual Mirror size control: Via Alt-K, you can now also select the size of your virtual mirror from a drop-down menu.
- Black Boxes: These now have minimised and expanded states. The expanded state displays additional columns.
- Real-world clock: You now have access to your local wall-clock time via the F1 menu and also via an optional dedicated widget.
- Camera Tool redesign: The Camera Tool is now accessible via a dedicated button found on the Session screen, and the tool itself is now more logically presented following a design update. The Ctrl-F12 binding is still available to toggle the Camera Tool.
VR improvements
A new foveated rendering system will be implemented in Season 4, helping prioritise your PC’s rendering capabilities on the areas of the screen you’re actually focusing on.
Using eye-tracking (if your VR headset supports this), iRacing should prove to be less resource-intensive when in VR, helping keep frame rates – and immersion levels – up.
Future developments
Hill also teased several new cars and tracks set to arrive in future builds, which are detailed below. You can find out more information on these in our companion article.
Ongoing work is being done on the sim’s graphics update too, with the career mode, AI performance and physics all being fettled in the background.
New tracks
iRacing has officially signed a deal with the St. Petersburg street course owners. The track is used across several of North America’s premier motorsport categories, so it should be a popular addition.
The Miami International Autodrome will be added to iRacing in the Season 1 2026 build, with Adelaide, Wheatland and ‘new locations in the EU and the Middle East’. Intriguing.
New cars
The FIA-approved Cross Car will also be added in the Season 1 2026 build, providing another entry-level off-roader for iRacers to enjoy.
What are you looking forward to most in iRacing’s Season 1 2026 build? Let us know your thoughts in the comments below.
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