American open-wheel series IndyCar has announced a host of regulation and chassis changes set in stone for the 2028 season.
Dallara will again be the lead designer of the chassis, extending a 20-year partnership with IndyCar.
The new chassis, named the “IR-28,” is set to revolutionise the ‘Fastest Racing on Earth’. The revised ergonomic structure of the car will be vital for improving lap times, wheel-to-wheel racing, and driver safety.
In a press statement, IndyCar president J. Douglas Boles said. “As you can imagine, a project of this magnitude takes an incredible amount of planning, collaboration and execution.” Boles thanked Dallara and four of IndyCar’s main partnerships for their input into the upcoming changes.
He said. “I would like to thank all of our partners, including Dallara, Chevrolet, Honda, Firestone and Shell, who have worked tirelessly to create a package that will enhance IndyCar’s already incredible competition and growth.”
The Biggest Changes to the Machines
With changes to the chassis and regulations, the IR-28 will be powered by a new 2.4-litre twin-turbo V6. Designed and developed by Honda and Chevrolet, the two engine suppliers to the NTT IndyCar series.
The engine was projected for 2023, an upgrade from the 2.2-litre engine currently used, but was shelved.
So both Honda and Chevrolet have agreed to incorporate their decommissioned development into their new designs.
The 200cc increase shall allow for more power without subjecting the units to extreme internal pressures. A starting point of 760hp has been agreed, but parties hope to target 800hp in future development.
With the increase in power comes some much-needed weight reduction.
Components of the hybrid system developed by XTrac, Helix and BOLD Technologies will remove approximately 9 kg from the car’s weight.
XTrac has commissioned a new six-speed transmission that, in addition to delivering hybrid power, will reduce the gearbox’s overall weight.
The new gearbox will be 11 kg lighter than the current gearbox in the DW12.
BOLD Technology is responsible for supplying a battery-based ESS, moving away from the supercapacitors. IndyCar says this change will ‘offer 14 times the energy storage over the DW12’s system’.
Helix will handle the motor-generator unit of the hybrid, with the three manufacturers developing a lighter system than the current system supplied by Skeleton and Empel.
The IR-28 chassis will feature an all-new aeroscreen that smoothly blends into the car’s design.
A harmonious change when compared to the bolted aeroscreen added to the DW12 in 2020.
The aeroscreen will be mounted to a titanium halo and carbon-fibre frame. New digital panels on the sides of the screen will project information digitally for drivers to see.
New front and rear wings will be optimised for efficiency and used in the three aerodynamic packages. Each package differs for the street, road and oval courses in the racing series.
Dallara Has Developed the Car from Scratch
After Jay Fyre was removed as IndyCar president in February 2025, Dallara proposed a question to the vice president of competition and race engineering, Mark Sibla.
To stick with previous development on the chassis (which had been in development for a decade) or to go in a new direction they’d been planning.
In March 2025, design engineers at Dallara showed Sibla their 50% scale model wind-tunnel of the chassis.
Meaning that over the last 17 months, the IR-28 has been redesigned from scratch and is Dallara’s initial prototype they’d been developing as a side project.
First Sighting of the Ir-28
Over the previous weekend, Indy500 winners Alex Palou and Alexander Rossi tested the IR-28 for the first time on the Indianapolis Motor Speedway.
It’s reported that Rossi set an unofficial lap time of around the 1m12s mark over a 40-lap stint. Glossing off a session that had no substantial technical delays.
The Ed Carpenter Racing driver said. “I’ve been a part of some new car launches before, and I can’t say any have gone as smooth as this one has.”
Four-time IndyCar champion Alex Palou described the car with great admiration. The Spaniard said, “The car feels a lot smoother, a lot more connected. I wouldn’t say easier to drive, but it just feels like you don’t need to fight crazy with the car.”
Palou managed to drive 35 laps at the Speedway despite damp conditions affecting some of the rundown.
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