The IZOD IndyCar Series continues to fine tune its technical regulations, with further changes to the recently re-introduced "push-to-pass" overtake system in time for this weekend's race at Sonoma Raceway.
The push-to-pass button adds 200rpm of extra turbocharger boost to the power output of the 2012 specification 2.2-litre V6 engines to make overtaking moves possible on street and road course circuits, in a rough equivalent to the DRS or KERS boost seen in F1.
However, officials were disappointed when its main use at Edmonton was by race leader Helio Castoneves using it to hold off Takuma Sato in the last 15 laps of the race. Castroneves was able to deploy the system at the direction of his pit crew who could see real-time information about other competitors using push-to-pass from the live TV feed and timing and scoring system.
As a result, for the following race at Mid-Ohio the series introduced a five second delay between the pressing of the button and the power coming online, which meant that it couldn't be used fast enough in response to other cars attacking from behind and was only effective in planning overtaking moves in advance on cars in front.
After analysing the racing action from that race, IndyCar has now trimmed the activation delay down to 3.5 seconds for this weekend's GoPro Indy Grand Prix of Sonoma. The series also confirmed that drivers will have a total boost time of 90 seconds available to them for the duration of the race, in bursts no longer than 15 seconds in duration.
"All parameters of the push-to-pass system can be tailored to fit any circuit that play host to IZOD IndyCar Series races," explained IndyCar's director of engine development, Trevor Knowles. "Sonoma has shorter straightaways than what we had at Mid-Ohio, so we've adjusted the parameters of push-to-pass to fit this particular circuit. But the principles for use that were in place for Mid-Ohio have remained the same for Sonoma."
The series has opted not to introduce a recharge time between uses of the push-to-pass system at this stage. The system will be used only once more in 2012, at the following week's race in Baltimore, and will not feature in the mid-September series finale on the Auto Club Speedway oval course in Fontana, California.
Teams were able to test the tweaked power boost settings at the end of last week in their one day open test at Sonoma. Drivers used the time to get used to the revised layout of the track, formerly known as Infineon Raceway and before that as Sears Point Raceway.
The run down to the hairpin turn 11 has been lengthened by 200 feet to make a deeper turn, giving drivers more opportunity to out-brake their competitors and to get a better run out of the turn and set up a pass into turn 12. The exit from the Bus Stop (turn 9) has be widened, and turn 7 has been remodelled into a new hairpin. The changes make the circuit into a 12-turn, 2.31-mile road event.
The drivers seemed largely happy with the changes to the track after their first taste of it last Friday.