Returning champion Fabrizio Giovanardi says he has yet to get the most from his Motorbase Performance Ford Focus after his final pre-season British Touring Car Championship test.
The 47-year-old has rejoined the series this year and will sample the NGTC-specification tin-top cars for the first time.
He has conducted several test days for the Kent-based team, but says he has yet to unlock the true potential of the hatchback.
Rain ruined the running during the series' official media day test at Donington Park on Tuesday and Giovanardi said the lost track time could prove crucial.
"At this point, I need the time to do more testing but we don't have more time now," said Giovanardi.
"I understand the car much better now but we need more miles for me to find my perfect settings in the car.
"It is not yet ready for my style of driving. I had to be clear where to go with the car by the end of the [Donington] test, but there was rain and it meant the running was difficult.
"I think the set-up is close, but I am not there yet. I need more mileage."
Giovanardi set the 12th fastest time during his 34 laps at Donington Park.
The series kicks off at Brands Hatch on March 29/30.