“Regarding other changes to the technical rules, we will set the boost for road and street courses at 150kPa (21.75 PSI) with 160kPa (23.2 PSI) available during push-to-pass events,” he said. “That’s how we ended up this year but we wanted to formalize it for next year. The push-to-pass software may be changed to a set number of pushes rather than allowing the driver to turn it off and save it. That’s still under discussion.”

Asked if staying in that higher boost range for every type of circuit the series visits would be feasible (INDYCAR limits as little as 18.8 PSI for the Indy 500, for example), Bennett says more boost at every round would drive up costs through increased engine wear.

Dario Franchitti and Honda shocked the Chevy camp during the Indy 500 with more power and fuel economy at its disposal, and is tasked with finding a sustainable advantage in 2013. (Photo: Marshall Pruett)

“Any level of increased performance whether from boost, revs, etc., only serves to reduce the durability of the engine,” he explained. “One of the challenges we faced with E85 was that just increasing the boost past 150kPa didn't add a lot of performance. The engine becomes very knock limited and so the risk/reward [of] running above 160kPa was determined by the [IndyCar Engine Committee] group as not worth it.

"As development continues this could be improved, but we also have to consider the durability of the engine and the fact that the mileage limits are going to continue to increase.”

Bennett touched on the last change to the 2013 engine regulations, noting the slight increase in minimum mileage each engine must achieve before an approved change is made to install a fresh unit.

The original target number for 2012 was 2000 miles, but that threshold was relaxed slightly to 1850 miles when all of the engine builders struggled to reach 2000 miles without component failures.

As Chevy and Honda found increased reliability as the 15-round championship wore on, meeting the 1850-mile limit became more routine, which led the series to bump the minimum number back up to 2000 miles next year.

“It was the plan from the start to increment the mileage limit and the manufacturers are OK with it so we are going ahead,” Knowles confirmed.

Like his counterparts at Honda Performance Development, Bennett and the Chevy Ilmor team have every intention of reaching the rebuild threshold on a more consistent basis next year, but won't be surprised if a few curve balls are thrown their way.

“We continue to develop all the time and goal is more performance, fuel economy and durability,” he said. “Following the 2012 season we now have a certain amount of confidence in the durability engine.

“However as we increase performance and push the engine harder, we will undoubtedly uncover other durability concerns that will need addressing.”

Along with the limited number of items the engine manufacturers are allowed to change at will, new connecting rods and bushings are a open to a one-time redesign for 2013.

Revisions to the criteria that allows engine manufacturers to receive a performance upgrade (a two percent power deficiency, as specified in the 2012 rules) are also on the way for next season.

Marshall Pruett is SPEED.com's Auto Racing Editor, and covers the IndyCar Series. Before joining SPEED, Pruett worked in open-wheel racing for 20 years as a mechanic and engineer. He also contributes to RACER, Road & Track and Racecar Engineering. Follow him @MarshallPruett.