Reigning Indianapolis 500 champion Scott Dixon topped the speed charts as those teams and drivers already qualified continued to work on set-up options for next weekend's 93rd running of the event.
Dixon recorded the fastest lap of the day at 222.799mph on his fifth tour of the day in his already-qualified car, pipping Thursday pacesetter Mario Moraes' lap of 222.530mph.
"Any day you can be quick is a good day, even if it doesn't mean much because it was a practice day," the Kiwi commented, "It will mean more on race day.
"We had a three or four car tow, and the car was feeling pretty good. It's important to be among the top six or seven for the whole month, and that's what we've been trying to do. [The speed increase] could be a range of different things, so we'll just have to look at it. We just want to make sure we have a consistent car. We're working pretty much the same as everybody - get the most out of the race car, making the car consistent and working in traffic. We've been trying our set-ups all around from lunch time through the afternoon. The car seemed pretty good, but we're still looking for a little more consistency in traffic."
The non-qualified car of Townsend Bell and Team Penske front-row team-mates Helio Castroneves and Ryan Briscoe rounded out the top five, with Bell - running a second-week sister programme to Moraes - the fastest among those who have not yet qualified for the 33-car field. The American's top lap was 222.139mph, boosting his optimism about making the grid for next weekend.
"It was a great day for the Herbalife car," Bell reported, "We went pretty quick in the race set-up - ran the tyres out a couple of times - but the car felt really good. I've had the chance to run a couple of times here before, and it's nice. Each time, you come a little bit smarter in terms of what you need to have a good run on [race day], and I'm pretty happy with where we are. We had a chance to sort of inch our way toward more of a qualifying set-up on the last run. The car's obviously quick, and I'm really excited about getting it into the field tomorrow."
Oriol Servia, Robert Doornbos, Alex Tagliani and Tomas Scheckter, the latter making his debut for Dale Coyne Racing, were also among the non-qualified drivers who turned laps faster than 220mph on a day that ended 17 minutes early due to loose bricks on the famed 'yard' at the start-finish line.
"When you're in a car and you're at the Indianapolis Motor Speedway, it's a good day," Scheckter commented, "We played around a little bit in the morning, as I heard some comments from [team-mate] Justin [Wilson] yesterday and we worked on a different line of set-up. The car seems great, and I think everyone with the team is pretty excited, and so am I. The car feels very comfortable, and we had no problems trimming it out, so it's a good car; smooth straight out of the pits and flat-out."
The final eleven spots in the 33-car field will be set during Saturday qualifying, with Bump Day 24 hours later to determine the final line-up. Sunday appears to be taking on more significance, with Scheckter's deal likely to be followed by others, including, possibly, one for five-time 500 starter Roger Yasukawa, who is still holding out hope for a ride this weekend.