Chevrolet 'disappointed' by Honda's IndyCar development concessions

Though both manufacturers have permission to make limited upgrades during the winter, Honda will be able to submit additional changes for approval after IndyCar agreed it was at a significant performance disadvantage.

The championship's regulations allow for extra concessions to be made if the disparity between rival aero kits is considered "detrimental" to the series.

Jim Campbell, vice president of performance vehicles and motorsport for Chevrolet US, felt the existing development opportunity should have been sufficient for Honda.

"The existing rules already allow each manufacturer the opportunity to improve on the performance of their aero kit and engine for 2016," he said.

"So we are disappointed in the decision to invoke rule 9.3 [allowing extra changes].

"Chevrolet remains 100 per cent focused on preparing for 2016 competition to again give our teams the best opportunity to win."

Although Chevrolet took a comprehensive victory in the IndyCar manufacturers' championship and dominated qualifying, Honda drivers won six of the series' 16 rounds and Graham Rahal fought for the drivers' title with Honda equipment.

IndyCar CEO Mark Miles said both manufacuters "probably don't agree with everything we're doing, but so far have at least seemed to understand", and he stood by the series' desire to try to equalise performance.

"I'm going to make no apologies to anybody for following our rules and implementing them in a way that takes into account the concerns and the situation for all of our teams," he said.

"We think we're doing that responsibly."

Campbell argued that Chevy and Honda were given a level playing field, and his company simply did a better job.

"All manufacturers received the same set of aero regulations and subsequent updates," he said.

"I am proud of how our Chevrolet engineering team and partners worked continuously for nearly four years to prepare our kit for the optimal combination of downforce, drag and engine performance to give our teams the best opportunity to win poles, races and championships."