Mercedes is planning to bring some "unusual" new parts to test on his new F1 car this week at Barcelona, according to team boss Toto Wolff.
The team has introduced what appeared to be an evolutionary W07, the car with which it hopes to defend its double championship crowns.
However, Wolff suggested the team will run some more innovative components later this week.
"We are having some bits which are slightly unusual," said Wolff. "We are not sure whether they come on the car tomorrow or after tomorrow.
"It depends on the analysis of the data from today was, but certainly some things to look at. Certainly when I saw it the first time I was surprised."
Lewis Hamilton finished the opening day of testing in second place today, but was the busiest man by some margin, covering 158 laps.
Wolff admitted the day had gone very well for the team.
"You shift your expectations and what you are trying to achieve, when it went so well like last year there is still room for progress, and our plan for today was to do lots of lap and lots of mileage, to collect data and check various systems and correlation, before we head into the next phase, and this is looking at performance – starting tomorrow, after tomorrow.
"So the day really went well, we had the plan of clocking so many kilometres, and when we discussed it with Lewis and Nico [Rosberg] before testing, and Paddy [Lowe] was saying we might be doing 700, 800, 900km a day, it was an ambitious target.
"But we showed the team was capable of achieving that and the drivers capable of holding on to it."