Getting To Know: The IMSA iRacing Series

The term “endurance racing” conjures visions of man and machine competing over 24 hours, covering vast distances fighting the elements, other cars, reliability, as well as the clock. Examples of this are the 24 Hours of Le Mans and the 24 Hours of Daytona, which are both classic races amongst many others.

But, can you take that essence and convert it into a bite-sized, virtual form? With the official iRacing IMSA SportsCar Series, you can get the delights of modern-day endurance racing condensed into a much shorter but just as exciting format. Let’s learn more about the series.

The Cars

Just like in the real-world IMSA WeatherTech SportsCar Championship, three classes of cars compete in the iRacing IMSA SportsCar Series, comprising two prototype categories and one for GT cars. 

Despite there being multiple categories of classes within each race, you only need to concern yourself with the other cars in your class. The category you choose will change how you have to manage traffic throughout the encounter, for example, if you race in GTP you’ll be continuously overtaking slower cars while in GT3 you’ll be being overtaken yourself more often.

GTP

Grand Touring Prototype (GTP) is the premier class in IMSA, featuring cars that represent the pinnacle of prototype technology with performance to match, partly due to the inclusion of a potent hybrid-drive system. iRacing currently has five cars in this category built to the LMDh regulations that feature hybrid technology and huge amounts of downforce, fast cornering, and very high top speeds.

• Acura ARX-06 GTP: This machine is built upon an Oreca-designed LMP2 chassis and features an HPD-built turbo V6 paired with a 50kw electric motor. The ARX-06 currently competes in the IMSA SportsCar Championship and has won several races, including the 2023 Daytona 24 Hours.
• BMW M Hybrid V8: The car is based on a Dallara-built chassis featuring a BMW twin-turbo V8 engine and a 50kW electric motor. The car currently competes in the IMSA SportsCar Championship and has already won one race. It will be entering the FIA World Endurance Championship next year.
• Cadillac V-Series.R: Based on the same Dallara chassis as the BMW, the V-Series R uses a normally aspirated V8 engine combined with a 50kW electric motor. The V-Series.R has already won two races in the IMSA SportsCar championship and finished third and fourth in the 24 Hours of Le Mans.
• Ferrari 499P: Unlike its GTP class rivals, the 499P features a custom chassis designed and built by Ferrari themselves. It also contains a bespoke twin-turbocharged 3.0-liter V6 with the prancing horse’s own hybrid system. This is because it is built to the World Endurance Championship LMH rules in real life, which allow manufacturer-designed systems. It’s BOP’d to the other GTPs in reality and in iRacing though.  
• Porsche 963 GTP: The 963 is based on a Multimatic-designed chassis and features a twin-turbo V8 mated to a 50kw electric motor. This vehicle currently competes in both the IMSA SportsCar Championship and the World Endurance Championship. It won races in both series, becoming the first LMDh car to do so.

Coach Dave Academy provides specially built setups for each of the GTP racers featured within iRacing, so you’re covered in whichever direction you decide to tread. 

LMP2

Le Mans Prototype 2 (LMP2) is one step down from the GTP class, but some may argue that it’s maybe one step up in terms of driveability and enjoyment. The class only features one model, and that’s the Dallara P217 – a prototype that runs on a chassis similar to the GTP cars but does not have any hybrid technology. 

It’s not too far off the pace of the GTP field but does not have any complicated ERS modes to worry about during the race. It’s lighter than its GTP counterparts too, which aids low-speed maneuverability. In parallel though it also boasts less downforce, so you won’t be able to carry as much pace through faster corners. 

GT3

The GT3 (known as GTD in IMSA competition) class comprises ten cars representing ten different manufacturers, all complying with the FIA-specified GT3 regulations. The cars have relatively high downforce, ABS, and traction control. The relative performance of each vehicle is equalised by iRacing’s Balance of Performance (BOP) system.

• Acura NSX GT3 Evo 22
• Audi R8 LMS GT3
• BMW M4 GT3
• Chevrolet Corvette Z.06 GT3.R
• Ferrari 296 GT3
• Ford Mustang GT3
• Lamborghini Huracán GT3
• McLaren 720s GT3 EVO
• Mercedes-AMG GT3 2020
• Porsche 992 GT3 R

Need Setups For The Series?

Our iRacing Setup Subscription allows you to focus purely on your on-track performance. And, with access to our free Coach Dave Delta app, installing them couldn’t be any easier.

Race Format and Strategy

There are two different IMSA SportsCar formats available within iRacing. There is an open setup series that allows unrestricted changes to the car setups. These races are 45 minutes long, with one compulsory pit stop.

There is also a fixed-setup race format, which limits any setup tweaking to the brake bias setting. These contests run over a slightly shorter 35-minute distance compared to the open events, though still feature a pit stop.

• Both series begin under a rolling start procedure following an eight-minute qualifying session that grants you two laps to set your best time.
• At all tracks, you are able to run a BoP-restricted, smaller tank of fuel at the start which should see you get far past the 50% race distance mark. You must plan your stop to give you the best performance advantage.
• Being able to fuel-save in both series can provide a huge advantage, as the less fuel you use the less you’ll need to take in the pit stop, and thus the faster your stops will be.

Alongside your fuel level, you’ll also have to worry about your tyres, but these can last the full race distance. However, depending on the track type, track temperature, driving style, and car setup, you may find yourself with heavily worn tyres by the chequered flag. 

• Many drivers do stop for tyres but only take two per stop as the time taken to change them is covered by the amount of time it takes for fuel to be added.
• Changing tyres on only one side will likely cause handling imbalance, so caution must be taken, especially on out laps if you elect to change them.

All in all, you’re going to lose a lot of extra time by changing tyres in the IMSA iRacing Series, so it’s something you’re going to want to avoid doing in most circumstances.

Bolting on a Coach Dave Academy-prepared setup can help you save your rubber more effectively as you won’t need to push as hard to make lap time. 

Traffic Management

It’s important to note that traffic management is vital in achieving good results in IMSA, and knowing where and when to pass slower cars can make a huge difference in lap times and your overall race time. 

• Focus on racing the cars in your own class, it’s best to steer clear of cars in other classes. 
• If you’re in a slower-class car, it’s good practice to maintain your racing line when a faster-class car is attempting to lap you. 
• This is a predictable and consistent way for other drivers to know your intentions, meaning they can use the performance of their car to pass you without interfering with your race or getting tangled up in an unnecessary incident. 

What License Is Needed To Race?

Both IMSA iRacing series require an A level license to participate, making it the highest-level multi-class series you can reach in the service.

Running in the C license level Falken Sportscar Challenge is a good way to prepare for the kind of competition you can expect to find in the IMSA series.

Series Costing

The pair of IMSA iRacing series championships are towards the higher end in terms of pricing to complete the season due to the paid track-based schedules they run.

For 2025 Season 1 all 12 tracks that make up the 12-week season are paid for, which adds up to around $180 to run every round. Add this to the $11.95 cost for a vehicle eligible to race in the series, and you are looking at a minimum of around $200 to run the full season. However, there are a plethora of ways that you can save money when starting out in iRacing as detailed by our guide here.   

Conclusion

The iRacing IMSA SportsCar Series is the most popular multi-class series on iRacing and features full grids and multiple splits over most of its time slots. The racing is very competitive, with traffic management quite often determining the winner. However, learning how to manage traffic and not getting into unnecessary incidents may be the difference between winning and losing.

Also, remember to download the free Coach Dave Delta app today to access the full range of setups to fight for supremacy whenever you hit the track!