iRacing Season 4: new cars, rebuilt tracks and a September 15 start

iRacing’s Season 4 build is available ahead of the official season start on September 15 at 00:00 UTC. The September 9 release updates established circuits and race-management tools as well as adding cars, so the changes reach beyond drivers buying new content. [1]

Four cars and three rebuilt circuits

The Aston Martin Valkyrie AMR-LMH, Caterham Academy, Caterham 420R and Gen 4 Grand National join the simulator. Both Caterhams are sold together, and they and the Valkyrie support rain from release. [2]

New cars and wet-weather running

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Road America, Mid-Ohio and the Milwaukee Mile receive complete replacements based on new scans. Summit Point and Road Atlanta receive artwork upgrades. These are different kinds of updates: the three rebuilt venues replace their earlier versions, while the latter two are listed as visual improvements. [1]

Circuit layouts and artwork updates

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More information during practice and pit stops

A Reference Car interface shows control inputs in solo sessions. New Pit Summary and Car Damage widgets expand the in-car display, with damage information limited to supported cars. A Minimal interface mode lets drivers reduce clutter while retaining pinned elements. Team registration also gains a verification step showing the drivers and team before submission. [1]

The updated in-car interface

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Multiclass starts remain conditional

Per-class pace cars are planned for IMSA after a successful Week 13 test. The release notes also describe multithreaded physics processing and major Global Mazda MX-5 Cup and Sprint Car revisions. [1]

MX-5 and Sprint Car updates

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A September 11 hotfix is already available

The first Season 4 hotfix addresses Caterham rear-suspension damage settings and two simulator crashes. This means the launch build is already followed by a corrective update before the championship calendar starts. [3]

For teams preparing a season opener, keeping the build date, hotfix date and race-calendar date separate makes the release easier to follow. A new car being available in the simulator does not mean its first scheduled championship race has begun. Likewise, the dedicated pace-car system has its own testing condition within the wider release.

Offline racing also expands

iRacing’s separate AI announcement lists eight additional cars and 19 track configurations. The four new cars are joined by the Corvette C7 Daytona Prototype, Formula Renault 2.0, legacy BMW Z4 GT3 and legacy Riley MkXX Daytona Prototype. That extends the update to drivers using solo races to learn machinery or prepare for online competition. [4]

AI racing

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