Scott Dixon became the first driver in either test group to dip under the 52s mark at Sebring International Raceway this week, with the Ganassi-Honda driver setting a best time of 51.7932s (116.077mph) in the morning that was eight tenths clear of AJ Foyt Racing's Mike Conway (also running a Honda engine) in second place.
"Our car right out of the box was pretty decent," said Dixon. "I looked down at my dash and though there was an error, honestly, because it came pretty easy.
That makes Dixon the fastest man of the week, with the best time of the first group of ten cars that tested on Monday and Tuesday being Helio Castroneves with a lap of 52.1413s on the second day.
However, the times on the 1.67-mile, 11-turn short course are not directly comparable, and Dixon subsequently tweeted to Ryan Hunter-Reay (the fastest driver in Monday's session) that "[I] think you guys laid down some good rubber," which had improved grip for the cars running later in the week.
"We're not really trying to go fast at Sebring, but are trying to cover all the bases before we get to St. Pete," he insisted.
Dixon repeated his sub-52s feat again in the afternoon, although the rest of the field had by now closed up on him - led by Dixon's own Ganassi team mate Dario Franchitti, who lost time in the morning session while his car was fitted out with Dallara's modification package to allow the Scot to stick with right-foot braking. A further unspecified issue meant that he only got five laps in during the morning, but he was able to complete 32 laps in the afternoon.
"The first session was a wash out really," admitted Franchitti. "I think I did some out laps and the most I did was two together. It was nice to get this afternoon and see where we were - it's not bad.
"There are so many things we're trying to change, it's not about shooting the car for the track, it's about learning and getting data," he continued. "The difference being, with the old car we pretty much knew what we were going to do."
Rubens Barrichello proved in good form in his first IndyCar open test, running sixth fastest in the morning but then popping up to third fastest for the day during the afternoon session with a time of 52.6745s (114.135mph) just 0.0644s off Dario's fastest effort of the day.