A two-day wind tunnel test last week proved that the Dallara DW12 chassis is now up to the task on ovals, according to IndyCar vice president of technology Will Phillips.
Questions arose during testing in November at the Indianapolis Motor Speedway as the chassis achieved only an average lap speed of 215.6mph on the 2.5-mile oval. IndyCar and Dallara arranged the full-scale, rolling test at the Windshear facility in North Carolina to discern what could be done to increase aerodynamic performance.
A 2011 Target Chip Ganassi Racing IR11 chassis in qualification trim that recorded a 227.34mph lap speed at the Speedway in May was utilized as a baseline reference.
"We then compared the 2012 car as it was run at its fastest during the testing at the Speedway," Phillips said. "We showed that aerodynamically the car was limited to 218.4mph, so the (drivers/teams) did a good job of reaching its potential. We then compared the production car, which is slightly different from the prototype in terms of different mirrors, different rear wheel fairings, subtle differences in chassis construction and better integration of the Zylon [side intrusion] panels.
"Basically, the car is more slippery. That lifted the speed as the car was run. We then looked at how we could improve the aerodynamic force of the car. Basically, by optimizing the aero setup, re-balancing the car and then putting on some aero development parts, it showed that using a nominal assumed horsepower of 575 the car is easily capable of 225mph.
"Same test at same venue using an '11 car and '12 car, and that's the only data we're using to compare," Phillips added. "It's about as clean as we can make it for a two-day test."
With the introduction of multiple aerodynamic body kits scheduled for 2013, the potential for higher speeds will be an item IndyCar officials will have to address, Phillips said.
"As we look at aero kits for 2013, the car could be exceeding expectations as they reduce drag further," Phillips agreed. "But it's not always about aerodynamics. You have to mechanically set the car up to drive it, so it's always a balance. Aerodynamically, we've proven that it can happen but we haven't proven mechanically that we can set the car up to go that speed yet."