iRacing: Development Update August 2025

iRacing is rolling out its new Development Update for August 2025. With the Season 4 build just around the corner, it’s the perfect time to share the latest progress in our simulation development.

Without further ado, here are the official notes for this update.

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Hello iRacers,

It has been a busy summer at iRacing, with numerous milestones achieved across our various teams. The NASCAR 25 team is well-positioned for the October 14th release of N25, having just passed console certification on the first attempt. The Orontes/ExoCross team now has a robust racing game engine foundation, and are well underway on their next racing title – more to come on that in the coming days! iRacing Arcade is rounding into form, offering a fun and refreshing blend of arcade racing and customization, with real-world racing properties and licenses (check out the new teaser trailer). Meanwhile, the sim team is about to launch our most substantial feature release since rain: the New Sim UI. What an exciting time at iRacing! Over the following months, we will reveal much more about these projects, sims, and games.

Returning to a sim focus, there is one thing I can share a great deal about today – the iRacing Developer Update! Let’s go over the Season 4 build, review our new content, improvements, and features, and touch on future development projects as well.

Season 4 is packed with numerous new features and improvements. Highlights include:

• Multiple compelling new cars
• A world-renowned new track and several track rescans and refreshes
• The final third of the “NASCAR Refresh” project
• A significant car class physics overhaul
• A powerful new feature for VR users
• Expanded and improved AI features
• A significant step forward in improving iRacing’s global reach and international support
• And, of course, the new UI!

We’ll begin with content…

Car Development

iRacing is the place to be for GT3 sim racing, and with Season 4, we are thrilled to announce the addition of the Aston Martin Vantage EVO GT3. Together with Aston Martin, the Vantage EVO was developed through close collaboration and support from Aston Martin and professional racers who pilot this car in real life and also have significant experience in sim racing. The car looks stunning, is a thrill to drive, and is part of a wider collaboration with Aston Martin that will yield additional new cars in the future.

Along with the addition of the Vantage EVO GT3, the larger GT3 class has undergone tweaks to gear-ratio options on 6 of the 10 cars. This was part of the BoP process, bringing us one step closer to current real-world practice.

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Last season, I teased a new entry in our open-wheel offering, which I am pleased to announce is the Dallara IL-15, featured in the INDY NXT series. This 2.0-liter turbocharged 450hp-powered racecar is a rocket, offering an excellent option for racers seeking a high-performance yet approachable open-wheel series. The IL-15 will be positioned as Class C and available in Road and Oval Fixed series.

The IL-15 chassis is a full carbon-fiber monocoque with an integrated Halo device, and its suspension delivers precise control and responsiveness. Aerodynamically, the car provides a balance of downforce and drag, ensuring stability on ovals and agility through technical road courses.

Power is transferred through a six-speed sequential gearbox, operated via paddle shifters on the steering wheel, which replicates the shift dynamics of higher-tier vehicles.

A push-to-pass system, mirroring closely the INDYCAR implementation, delivers an extra 50 hp at the driver’s request. Activation is handled via a steering wheel button, and an on-screen gauge tracks the remaining boost time. This familiar boost-management interface ensures a seamless transition for drivers advancing from INDY NXT to the top-level INDYCAR series.

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GT4 racing has been a key focus for us over the past couple of years, and we have been working behind the scenes to expand the series with multiple new cars and licenses. This renewed effort begins with the introduction of the Ford Mustang GT4. The Mustang is an exciting new entry to the class, and the first North American brand in our GT4 series. This addition will be accompanied by a comprehensive overhaul of the GT4 class, with a release ready pending partner approval.

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GT4 Update: This update brings our latest physics modeling improvements to the entire GT4 class. Along with these improvements, we have focused on improving the correlation of the sim relative to the current IMSA Michelin Pilot Challenge Series ruleset. Baseline weight and engine power have been increased, while both dry and wet tires have been redeveloped using our latest tire model.

Top speeds will be higher and minimum corner speeds lower; this does mean the overall grip level has reduced, and iRacers should keep this in mind. This is a worthwhile trade-off for improved real-world correlation, and despite the reduced grip level, lap times are expected to improve by somewhere between 0.5 and 1.0 seconds per lap, depending on the track type and conditions. Note that the tire warmer temperature has been decreased. As with other cars that feature our latest tire model, a warm-up period is required; however, it is shorter than that of the GTP or GT3.

All cars in the class have received a chassis repass and improvements/updates that include:

• 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.

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BMW M4 EVO GT3: We have added the Evo upgrade to the BMW M4 GT3. This required substantial graphics and physics work, and the update will be applied on top of the existing BMW M4 GT3. Therefore, the update will be free for all iRacers who own the BMW M4 GT3.

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Hybrid Update: We have completed a fundamental overhaul, integrating the hybrid system into our latest power unit code structure. This has been done with flexibility in mind to accommodate the large variety of racing hybrid systems we have in the service. The GTP and hypercar class will seamlessly blend ICE and electric drive to match the maximum allowable power output at all times. In addition, the Ferrari 499P hypercar will have electric drive only when traveling at a speed greater than a specified minimum, and it will be able to drive electrically at multiple output levels. The Mercedes W12 and W13 cars will see a modest refresh, with the addition of a fast regen mode. We are planning for the LMP1 cars to have a larger refresh aimed at improving drivability. The INDYCAR hybrid system will be manual deploy only, and won’t be ready for September.

Track Development

Our Track art and production teams have been incredibly busy this summer, with a focus on balancing our numerous refresh and rescan projects with a renewed emphasis on delivering all-new, world-class racing facilities.

Autódromo Hermanos Rodríguez – Season 4 marks the debut of Mexico City. This world-class racetrack features real-world racing across multiple prominent racing series, including TCR, NASCAR, F1, Formula 4, Formula E, and numerous Touring and GT series. In iRacing, we have constructed 7 configurations that will provide racing opportunities across multiple iRacing cars and series. At 2,238 meters (7,343 feet) above sea level, the thin air results in less aerodynamic drag on the cars, allowing them to reach incredibly high top speeds on the main straight. Along with those higher speeds, there’s also less downforce as a result of the thin air, which makes cornering an interesting proposition.

Mexico City also offers a unique area where the track cuts through the stands of a former baseball stadium. This location will provide an excellent way to experience our future Audio Reverb feature.

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Oulton Park is one of the most raced tracks on the iRacing service, and a key part of many iRacing Rookie series schedules. We have been fortunate to have been racing at Oulton Park in iRacing for many years, and millions of laps have been completed. Our team has rebuilt Oulton Park’s artwork from the ground up, remodeling and retexturing all objects and scenery, retexturing the track surfaces, and updating the trees and foliage. Please note that this is an art refresh, not a rescan. This update is provided free of charge to all iRacers.

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In each of the past two builds, we have shipped art refreshes and track rescans for roughly 2/3 of the tracks that are part of the NASCAR schedule. With Season 4, we are thrilled to release the final third and mark the completion of “NASCAR Refresh”.

This final phase includes…

• 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 (we may hold this back until a patch)

It is worth noting that these ~30 track refreshes and rescans have all been made available for FREE to iRacers who already own these tracks.

That covers content, so let’s continue right along and touch on some of the great new features and improvements coming in Season 4!

Features and Improvements

I’ll start things off with what is genuinely the headliner of this season 4 build and an addition which has been years in the making and will pay dividends for iRacers for years to come – the New Sim UI!

New SIM UI

The iRacing Sim UI (let’s call it the legacy UI for clarity going forward) has served us well for many years, providing a dependable way to interact with the sim that we are all very familiar with. However, due to a dated and inflexible architecture, the legacy UI has limited our ability to expand the in-sim experience and has been overdue for a complete rearchitecture and modernization.

Approximately two years ago, we embarked on a journey to rebuild our sim UI, assembling a team of engineers, designers, and UX professionals to tackle this challenge. They evaluated several technical options before settling on integrating a modern and powerful XAML-based framework and UI platform. Through our evaluations, we were confident that the technology would meet our strict requirements for performance and multiple display types.

Throughout the project, the team has been focused on a vital factor: every critical feature available in the legacy UI had to function correctly in the new UI. iRacing is a deep and complex simulation that encompasses various genres of motorsport, each with unique requirements for how the UI presents information. When we open up and look inside the two primary simulation screens (which we refer to as the Session screen and the Drive screen), there are hundreds of toggles, sliders, dropdown boxes, control bindings, black box elements, text displays, and other interactive controls. It is far more complex than it initially appears.

At long last, the initial version of the UI is complete, and we are thrilled to be sharing it with you all.  Now for what to expect on day one…

Our focus for the release has been on delivering all the existing features represented by the legacy UI, with high quality and a familiar form, along with select expanded functionality, tweaks, and new features. Primarily, we wanted you to be able to start iRacing and continue with as little fuss as possible. That being said, we highly recommend taking some time during week 13 to familiarize yourself with the refreshed features (described below) and take a moment to customize your layout via Alt-K.

Of the refreshed features, here are the key highlights you should know:

• Tooltips: The vast majority of controls now display tooltips when you mouse over them.
• Sim Options redesign: Options have had a significant reorganization, 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 minimized 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.

It’s worth briefly touching on the new Options design. The new UI untangles and reorganizes our options into a more structured layout. The new presentation may require more scrolling and will necessitate relearning where options are located. To assist with this, our top priority feature post-release is a dynamic Search capability. The search feature will enable users to quickly find the setting and work with it immediately. Please bear with us for these first few months as we work on this needed improvement.

Moving forward:

Upon release, we expect to spend time addressing newly discovered bugs, collecting feedback from iRacers, and applying necessary tweaks. We are already working on features and additions that are part of our UI advancement roadmap, and these efforts will accelerate. What’s on our roadmap, you might ask? We’re not ready to discuss these features in detail just yet, but some of the initial features we’re exploring (and developing) include adding the aforementioned text Search feature, color themes and accessibility views, customization of the driving screen, expanded information, light telemetry capabilities, new post-race functionality, VR-specific features, minimalist considerations, and localization.

Oh, and something to do with Black Boxes……

We are incredibly proud of the new UI and excited to share it with you all. This marks a new era of opportunity at iRacing, with a new technological foundation that will power experiences and features in ways never before possible.

VR

VR is a core way to experience iRacing and has been a focus of ours since the technology’s infancy. With Season 4, we continue our push to stay at the forefront of VR technology with the addition of eye-tracking foveated rendering. This technology is an evolution of fixed foveated, and shares some of the same core benefits – processing power is prioritized in the most critical areas to maximize performance and framerate.

For headsets that support this feature, fidelity is prioritized exactly where your eyes are looking, regardless of the direction your head is pointed. This allows racers to move their eyes anywhere across their field of vision and experience a crisp, clean image at all times, with high frame rates and fast refresh rates.

Note there’s a slight chance we’ll hold this for a later update, as it still needs to pass through QA.

Rendering

As part of our longer-term initiative to rebuild the iRacing rendering engine, we have found opportunities along the way to bring more immediate benefits to the current iRacing experience. With Season 4, we continue this trend by introducing new technology that sets the foundation for significant improvements down the road: modern texture compression. This tech replaces our former texture compression and is substantially more efficient and performant.

Generally, this change should be transparent to iRacers (aside from some initial downloads), with benefits occurring behind the scenes during the rendering process. I hesitate to give too much away, but I will say that the savings in texture footprint have our car painters salivating for future e x p a n s i o n of paint capabilities…

Localization

We are excited to share that iRacing is now a far more globally accessible product – with Season 4, we will support language localization in iRacing & iRacing Web (the sim and companion app are not quite yet supported). This project involved substantial technical architecture changes, as well as the establishment of processes and workflows to translate vast amounts of text that is often contextual and nuanced, requiring subject-matter expertise. There are some features that will be rolling out during Season 4 to translate things like car & track descriptions, achievements, and other dynamic text. Stay tuned for news on those features!
To begin, we will launch with European Spanish.

Latin Spanish, German, French, Italian, Portuguese, Brazilian Portuguese, and more will follow in the December and March builds.

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That covers the bulk of the Season 4 build. We’re proud of all our builds and releases, each of which requires substantial effort and commitment from our team. Season 4 is a special release that was years in the making, and we are thrilled to share it with you all.

Ongoing Development

Let’s touch on some future initiatives, content, and plans before we close out this update.

Graphics

The new rendering engine is making tremendous progress every day. One of the more visual improvements that the team has made recently will have a substantial impact on the overall scene. You may or may not have noticed it, but the trees in iRacing do not receive shadows. This is because the technical system powering the tree rendering is not integrated into the core rendering. The new rendering engine has solved this, and trees receive shadow. The visual improvement is substantial, transforming the appearance of the world.

A few additional areas of progress since our last update:

• Shadow rendering has advanced substantially and will transform the look of the sim
• Headlights are now in, as is the ability to do separate light rigs.  Night lighting in the new renderer will be transformatively better.
• Decals and our Dynamic track system are now integrated
• We have a DLSS prototype working and performing very well

Overall, the project is moving along on schedule, and we will share additional insights over the coming months.

Tires and Physics

We have several significant physics projects underway, including foundational tire modeling, force feedback, physics rate, and peripheral system advancements and rearchitectures.

With tires, we have transitioned to a new modular architecture designed for the future, featuring clearly defined interfaces between components.  We are implementing changes to spread the work of physics/sounds/AI/etc.to multiple cores. This will enable us to operate at a higher sampling rate, thereby improving accuracy and reducing latency in response time.

Summing all this up, we expect to have very accurate tire forces transmitted through the steering wheel to your hands when and as they should be felt. The car will behave more realistically, and the connection between you and the road will feel natural.

Career Mode

Work is well underway on Career Mode, which leverages our AI driver capabilities to offer structured racing outside of our official racing series. In this mode, iRacers will advance their racing careers through various racing ladders and carve their path via success on the track. This mode leverages our AI drivers to their fullest potential, and the project has driven improvements across the entire simulation, including the addition of a Save Game feature. Career Mode in iRacing will be available to iRacers in new and exciting ways, offering tremendous value.

Beyond the opportunity for fun and competition that Career Mode offers, it also serves as a valuable platform to practice driving skills, refine racecraft, experience different cars and tracks, and more.  For many, this may be a great lower-pressure on-ramp to prepare for direct online competition.

We are not ready to provide a release window for Career Mode, but note that multiple development teams are working on it as their top priority.

Miscellaneous

A few items of interest in no particular order that surely will be of interest:

• Gen 4 drafting has been reworked and improved. This will ship with S4.
• Oval Refresh “Phase 2” did not advance with the immediacy we originally intended, and we had to take a step back and assess broader implications. The team is re-engaged and eager to improve oval racing in iRacing.
• We are exploring opportunities to improve dirt oval racing across many systems, including the tires, track dynamics modeling, and rulesets.
• Our machine-learning AI project with Microsoft is going tremendously well, and we have AI drivers performing with top-tier human-like capabilities.
• We plan for new Audio features to debut within the next several months that will be a step towards transforming the auditory experience of racing cars in iRacing.
• Race Control systems are advancing, including work on multi-class race starts and the choose rule.
• Dirt Oval AI has made significant progress, and development has advanced to incorporate our production teams.
• Adaptive AI continues to be tuned and improved, and we are working on an additional system that could provide you with an even better baseline to start each race.
• Our animation team has been chipping away at adding animated pit stops to one of our major car classes.
• Our animation team is collaborating with the physics team to establish a more seamless connection between the physics engine and the car and driver. This enhanced connection will power new features.
• Miami International Autodrome will be included with the Season 1 release.
• We have a handful of track refreshes underway for Season 1, 2, and beyond.

• We are happy to announce the addition of the FIA Cross Car to iRacing. The FIA first revealed this relationship in June, and the Cross Car will debut in iRacing with the December Season 1 build. The Cross Car provides an approachable and fun entry point to our dirt road racing series. The release will be further supported by the completion of the Off-Road track at Lucas Oil Speedway (Wheatland).
• Adelaide Street Circuit is well underway and is a substantial project.
• We have licensed the St. Petersburg street circuit, and work is well underway. It’s good timing to let you all know about this, given that NASCAR just announced that Trucks will race there next year. St. Petersburg has hosted racing events across INDYCAR, INDY NXT, USF, MX-5 Cup, and GT series. St. Pete will see heavy use across our iRacing series.
• Our production teams are gearing up for a handful of new track scans. Projects include scans and rescans of many prominent North American road circuits, as well as new locations in the EU and the Middle East.
• The car teams are busy working on future releases, as well as continuing the class updates we’ve now implemented across GTP, GT3, IndyCar, NASCAR, and GT4. We have plans to overhaul another key class of racing for S1.

We will share more information on these projects #soon, among many others in the works.

As always, we are focused on supporting and expanding our diverse range of racing categories, continuously improving the sim, and advancing our technologies to provide the most realistic simulated racing experience possible. With numerous foundational projects in the works, the iRacing sim is positioned for a tremendous next few years full of advancement with powerful new features. We are thrilled to ship one of the core building blocks for future improvement with Season 4 – the New SIM UI. The New SIM UI unlocks our developers, providing them with a powerful canvas for creating new systems and experiences in the SIM, and will take iRacing to the next level.

Thank you so much for your continued support and for choosing to do your sim racing with us here at iRacing.

See you at the finish line

-Greg