After setting the second fastest lap of the morning session, Tony Kanaan shaved nearly two-tenths of a second in the second session, topping the day's speed charts with a lap of 214.797 mph around the high-banked two-mile Michigan International Speedway.
Tomas Scheckter, who was the only driver to top 214 mph in the morning, didn't gain as much as Kanaan in the second session, ending the day third overall with a lap at 214.277 mph.
Kosuke Matsuura enjoyed a huge gain in the afternoon, posting the second fastest lap of the day. Knocking over half a second from his morning best, Matsuura was one of four drivers to break the 214 mph barrier. "I was very confident to finish in the top three today, but it doesn't mean anything," said Matsuura. "I'm thinking of how to race 200 laps. I don't think the race will be easy."
Buddy Rice ended up fourth, recording a lap at 214.276 mph in the afternoon. "With our recent success, we can come off the trailer in an aggressive or offensive mode rather than a defensive mode," said Rice. "In the past, we had so many things to change on the car that you can't get it all together. That isn't the case with this team. It is just little things that can be adjusted now."
Until this afternoon, Chevrolet-powered cars struggled to make it into the top-ten in practice. Scheckter's performance, with the fastest lap in the morning, and third fastest overall, fueled rumors that Chevrolet had made significant improvements to their engine. While Chevrolet did not announce any specific changes, GM Racing IRL program manager Joe Negri said, "Our development program for the Chevy Indy V-8 is continuing, and we've focused on the next step in the evolution of our speedway engine specification for the Michigan Indy 400. The 400-mile race distance is second only to the Indy 500, and we expect that teams will run different fuel strategies. We're optimistic that we have come up with improvements that will help Chevrolet-powered teams in Chevy's home race."
Four Chevrolet powered cars placed in the top ten today, with Scheckter's teammate Townsend Bell sixth and Ed Carpenter seventh. Carpenter's teammate Alex Barron rounded out the top-ten.
"I think Chevrolet has been working hard, and it's showed," said Scheckter. "This team was struggling last year, but Chevrolet stepped it up for them over here, and hopefully they'll do it again for us this weekend."
Toyota-powered cars struggled today with Sam Hornish delivering the marque's best lap at 213.068 mph, 12th fastest on the day. Despite being nearly three tenths of a second off Kanaan's time, Hornish was optimistic. "We're still not quite where we need to be, but the team is working hard to make sure we're ready for Sunday. We focused on race setup and running in traffic to see how the car is handling. Tomorrow morning we'll trim the car out and make sure we're ready for qualifying."
Townsend Bell was involved in the only incident of the day when he spun exiting turn two and made contact with the outside wall. "It just kind of got away from me," said Bell. We'll have to look to see what happened. Something went wrong, I'm not really sure." Bell was checked and released from the infield care center and has been cleared to drive.
In the abbreviated practice session for the Menards Infiniti Pro Series, Paul Dana was fastest, followed by Al Unser, Arie Luyendyk Jr. and Thiago Medeiros.
The starting line-up for the NASCAR Craftsman Truck Series race will be determined by team owner points after rain washed out qualifying.