After setting fastest unofficial time in Jerez testing after the second day, Grosjean said: "The world title is not my goal."
McLaren on Tuesday, Lotus' Romain Grosjean went quicker still as a second test day came to a close at Jerez.
But Frenchman Grosjean - banned at Monza last year and written off as a "first lap nutcase" by Mark Webber - insists he is not getting carried away with the tantalising potential of the new black E21.
"The world title is not my goal," the 26-year-old is quoted by Auto Motor und Sport.
"In 2013, I particularly want to be consistent. I know that the speed is there, in me. But in some situations I have to be more patient," added Grosjean.