Ferrari is set to introduce new aerodynamic components on Friday, as it gradually upgrades its aero package during Barcelona's final pre-season test.
Kimi Raikkonen set the sixth-fastest time for the team on the opening day, having spent the bulk of his 80 laps on the hard and medium Pirellis.
While new components on the car for Thursday were minimal, Raikkonen is keen to run the updates on Saturday as he alternates days with Sebastian Vettel.
"More or less the car is the same," he said of developments compared to last week's test. "We can get some, but not for today, hopefully for tomorrow.
"I think it's not too bad, really, how the car behaves.
"There are certain things that we want to improve - and we want more grip obviously, always, to go faster - but sometimes it's a bit tricky here with the conditions that we are having.
"If the tyres don't work - one lap they work, next they don't - it changes a lot."
Raikkonen is content with the visible progress Ferrari has made after enduring a troubled 2014 season, especially as he knows there is more to come.
"We've made a good step from last year. It's hard to say from testing, but two weeks will tell us once we're going in Australia," he said.
"Overall it's a good a feeling and we still have one day to put all of the things we have learned together and hopefully we will be happy with everything.
"Obviously a laptime would be good, but we'll see in a few weeks in the first race where we are.
"It's not an issue, as long as you've got a good feeling on every fuel load you run it's usually OK."
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