Updated

Scott Dixon and Dario Franchitti paced the four days of IndyCar spring training.

The Target Chip Ganassi Racing teammates posted the fastest laps at Sebring International Raceway. Dixon also provided some excitement Friday afternoon, when he knocked four-time champion Franchitti off the leaderboard on his final lap of the test.

Dixon's lap of 51.7938 seconds right before the red flag bettered Franchitti's lap of 52.0157 set earlier Friday afternoon.

"We did the work on the car and as the sun went down a bit and the clouds came in, the track picked up some time," Dixon said of his final run. "We definitely worked to make the car better as well. I was good to do something for the lads at the end and it worked out."

Dixon's best lap of the four-day test actually came Thursday morning, when he posted a 51.7932. It held over all 27 drivers.

Helio Castroneves was third with a lap of 52.1413 on Tuesday afternoon for Penske Racing. Former Formula One star Rubens Barrichello concluded his first official test as an IndyCar Series driver fourth on the chart with a lap of 52.1615 on Friday morning.

Will Power was fifth and was followed by JR Hildebrand, Ryan Briscoe and Mike Conway. Ryan Hunter-Reay and Takuma Sato rounded out the top 10.

The test was a struggle for the Lotus teams, particularly Dragon Racing, which had just one engine for its two drivers. Sebastian Bourdais was scheduled to be on track at the start of the week, but ultimately ran only Friday morning.

Katherine Legge, the second Dragon driver, ran Thursday afternoon and Friday afternoon.

Bourdais got 69 laps in, but his time of 53.2993 ranked 24th.

"Nothing is ideal, we would have loved to get more done, but at least I will show up in St. Pete having done some laps in the car," Bourdais said. "And knowing a little bit, making sure the car was right and was doing everything it was expected to do, and to get the communication going with the engineers is what we need to address and to get the communication going with Lotus as well. Just slowly starting, really."

Indy Lights champion Josef Newgarden turned his first laps in the new Dallara DW12 for Sarah Fisher Hartman Racing. His first day on the track Thursday at the higher level was a challenge, but he hit a groove by Friday afternoon and ended up 15th overall.

"It's pretty cool. It's an IndyCar! Not many people get to drive an IndyCar in their life, and I think it's pretty phenomenal that I get to work with this great group," said the 21-year-old from Nashville, Tenn.

The season opens March 25 at St. Petersburg.