Dallara IR18 is the chassis currently used in the IndyCar championship, known for close racing, raw driving experience and complexity required to master ovals, road and street circuits in the calendar. With the new licence agreement secured with IndyCar, it presents the perfect opportunity to experience this car in iRacing now it has returned to the platform.
Introducing Dallara IR18
Following the tragic loss of fan-favorite driver Dan Wheldon in 2011, IndyCar introduced the updated DW12 chassis for the following season. Despite its unconventional appearance, the DW12 was hailed as a significant advancement for the championship. It maintained thrilling racing while significantly enhancing driver safety, particularly on oval tracks.
The DW12 chassis has undergone three iterations since its introduction. Initially offered in its spec form by Dallara, the first iteration of DW12 remained in service until the 2015 season. Subsequently, IndyCar allowed teams to implement aerodynamic updates from the two active engine manufacturers, Honda and Chevrolet.
The specifications were frozen again in the 2017 season, ahead of the planned introduction of a new universal aero kit for 2018. The third iteration of the DW12 chassis, the IR18, featured a sleeker and more aggressive design than its predecessor.
The Aeroscreen, a cockpit safety device similar to Halo in Formula 1, was added to the IR18 for the 2020 season. Unlike the Halo, the Aeroscreen featured a fighter jet-style full cockpit wraparound screen.
This latest spec of IR18 is used in IndyCar and is expected to remain in service until the 2026 season.
The IR18 was first introduced to iRacing in 2018 and later updated according to the real car, but then vanished from the platform for a short while. iRacing secured a new licence deal with IndyCar in 2024, so you can experience official championships on the platform again, including the legendary Indianapolis 500 special event from May 27th to June 2nd, 2024.
The Basic Car Characteristics
The Dallara IR18 is powered by a 2.2-litre, twin-turbocharged V6 engine supplied by Honda or Chevrolet, depending on the team’s choice. These engines produce approximately 550-700 horsepower, depending on the circuit configuration and turbo boost levels mandated by IndyCar regulations.
As for the overall performance and iRacing Formula career ladder, the IR18 is below Formula 1 but above all junior series from Formula 3. The IndyCar championships usually require a B licence to participate.
The IR18 is one of the few cars in iRacing used on road and oval circuits. The setup, handling and even some sporting regulations are quite different, and we will cover them separately.
Road and Street Circuits
If you have followed the iRacing career ladder and moved from Formula 4 to Formula 3, progressing to Dallara IR18 or Super Formula will be a logical step forward. Compared to Super Formula, IndyCar offers no power steering and it is arguably more difficult to master in driving, strategy and setup.
Firstly, one familiar feature is push-to-pass (P2P). It temporarily increases power output by 40 horsepower to facilitate overtaking or defend against other cars. Drivers can activate P2P at any point on the track for 200 seconds during a race without delay between activations. P2P is available only on road and street circuits.
Secondly, you have a tyre strategy with two compounds, Primary (Hard) and Alternate (Soft). The primary compound is slower but more consistent, and the Alternative is faster but degrades quickly. Drivers are required to use both compounds during a race. This does not apply to ovals, where only one compound is available for everyone.
The third and most interesting aspect of the IR18 is the fuel strategy. Unlike in most popular Formula championships, refuelling is allowed and you have 8 engine map settings to regulate fuel consumption. For example, you can use Fuel Map 1 (the highest power and consumption) the whole race for a two-stop strategy with two stints on Alternatives or Fuel Maps 2-5 for a one-stop strategy with one stint on Alternatives, which will require saving tyre. These situations often happen in IndyCar and reward preparation and planning over raw pace.
Finally, IndyCar uses rolling starts. It helps to space out the grid before turn 1, which results in fewer crashes than in formula championships with standing starts.
Oval Circuits
Fuel consumption is the main strategic consideration during an oval race. You can massively save fuel by running in the draft of another car and either save one pit stop or do it at a more appropriate time during the period of yellow flag.
The IR18 chassis for ovals has access to weight jacker adjustment during races. It serves as a mechanism mounted to the right-rear spring, enabling in-car adjustment of cross weight. When activated on the right rear suspension, the weight jacker will cause a diagonal load to place more weight on the left-front tyre, reducing understeer for the driver.
Remember that setups for oval and road circuits are completely different. You will also see changes in setup settings available for specific circuits. For example, the rear differential or third springs will not be adjustable for ovals, and some aero settings will vary even between short and large ovals.
Where You Can Race It
C Licence
The C formula licence is enough to participate in the official IndyCar iRacing Series – a huge 16-race championship that lasts multiple iRacing seasons. The 2024 schedule started on March 5th at Sebring International Raceway and will conclude on September 10th at Nashville Superspeedway. Like in the real IndyCar, the calendar includes road, street and oval circuits and the races last for the full distance.
The championship has only four timeslots for the race week: Thursday 1:00 GMT, Friday 20:00 GMT, Saturday 18:00 GMT and Sunday 2:00 GMT. This series is a real challenge for the drivers as they must master setups and race strategies for completely different circuits.
B Licence
If you prefer a more focused experience, there are three more championships for the holders of B oval or formula licences: the IndyCar Oval Fixed Series, the IndyCar Series Open and the IndyCar Series Fixed.
These championships offer races every 2 hours and follow a weekly schedule for circuit rotation during the 12-week season. Even though the IndyCar Series requires a Formula B licence, 5 circuits out of 12 are ovals. The calendar for the road circuits is very heavy on circuits in North America and loosely follows the real IndyCar calendar.
The race distance for the IndyCar Oval Fixed and the IndyCar Series Open is about half the full race distance used in the IndyCar iRacing Series. The races in the Fixed series are approximately four times shorter than the full race distance.
Here is the summary of all regular races available on iRacing for the Dallara IR18. The maximum grid per split is 26 drivers and at least 6 drivers are required to make the session official.
| Series | Licence | Setup | Type | Schedule |
| IndyCar iRacing Series | C (Formula) | Open | Road, street, oval | 4 timeslots per raceweek |
| IndyCar Oval Fixed Series | B (Oval) | Fixed | Oval | Every even 2 hours |
| IndyCar Series Open | B (Formula) | Open | Road, street, oval | Every even 2 hours |
| IndyCar Series Fixed | B (Formula) | Fixed | Road, street, oval | Every odd 2 hours |
Final Thoughts
The Dallara IR18 is arguably the most complicated and rewarding open-wheel car in iRacing. Although it is slower than the modern Formula 1 car or Super Formula, the balance between power and downforce, complex setup, race strategies and the diversity of circuits make it hard to master. This guide should help you on your way to becoming a better IndyCar driver.
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