Dallara and INDYCAR have completed the next validation phase for the IR-28, running the new chassis on the Indianapolis Motor Speedway oval after an earlier road-course test.
INDYCAR reported the results on 15 September 2026. Alexander Rossi drove for Chevrolet and Ed Carpenter Racing, while Alex Palou represented Honda and Chip Ganassi Racing. The series described the programme as validation rather than a record attempt.
Track data matches the design model
The oval running followed three road-course days in August and covered two superspeedway test days. Engineers used the programme to evaluate aerodynamic sensitivity, ride-height changes and the smaller wing package required for oval competition.
INDYCAR says Dallara parts were fitted and removed to compare track behaviour with wind-tunnel predictions. According to the series, the measured changes correlated with the design data and the test produced no unexpected interference between components.
That is a development milestone rather than final homologation. The IR-28 is not scheduled to race until 2028, leaving further testing, specification decisions and team preparation before the new chassis enters competition.
Powertrain targets move to Chevrolet and Honda
The car is being developed around a 2.4-litre twin-turbocharged V6 and an evolved low-voltage hybrid system. INDYCAR says the engine can produce up to 760 horsepower and that the revised power unit should be approximately 20lb lighter than the current generation.
Chevrolet and Honda have committed to the formula. Data from the Indianapolis running will now help the series give both manufacturers horsepower targets for the oval configuration.
Neither INDYCAR nor Dallara published a chassis price, team delivery schedule, final parts list or complete testing calendar with the update. Those details will be significant for suppliers and teams planning the changeover.
The verified development is that the IR-28 has now run in both road-course and superspeedway forms, with the oval data matching the expected aerodynamic responses. It moves the programme from launch specification toward a competition-ready package, while leaving two seasons for further validation and manufacturing preparation.