Castroneves tops times

It was the second time this week that the Brazilian, who is gunning for his third Indianapolis 500 victory in four years, found himself on top of the timesheets.

The 221.156mph lap recorded by Castroneves' in his Toyota-powered Dallara bumped Roger Yasukawa out of the top spot, minutes after the IndyCar Series sophomore had done the same thing to Castroneves' teammate, Sam Hornish Jr. Speeds were off slightly during Thursday's rain-delayed session. On Wednesday, Tony Kanaan notched the fastest lap of the week, 222.668 mph.

"The speed came down because of the rain," Castroneves said. "The track is a little green and a little more drivable because of the cooler temperatures.

"This place is very tough. You just have to be patient and go lap-by-lap and not panic."

With just over half an hour of practice remaining, Yasukawa's Rahal Letterman G Force-Honda knocked Buddy Rice off the top. Hornish started the final-minute barrage by topping Yasukawa with a 220.956mph lap. The Japanese driver answered back with a lap at 221.093mph. Two minutes later, Castroneves ended the dispute.

"We tried a little bit more stuff because we don't know what is going to happen (with Friday's weather)," Castroneves said. "We just have to wait and be patient. We don't know what the weather is going to be like. Right now it looks like rain, so we have to be prepared."

Honda still holds the five fastest laps of the week, all over 221 mph. Rain is in the forecast for Friday's final full day of practice before qualifying, but Saturday is expected to be dry and cooler, with a high near 70 degrees.

The session ended when Scott Sharp's car hit the wall hard in Turn One just after 5.30pm. He was not injured. "I just drove it in there and bam," Sharp said. "It just snapped and I was sideways. I don't even know what happened."

Britain's Darren Manning had the only other incident of the day when he brushed the wall on the exit of Turn One without damaging the car.