Briton Smedley, Felipe Massa's long-time race engineer at Ferrari, joined his Brazilian friend in moving to the Grove based Williams team for 2014.
Smedley, 40, is now Williams' 'head of performance engineering'.
He admitted that a major technical difference between Ferrari and his new employer is that new parts developed in Williams' wind tunnel always work as expected.
"At Williams, the correlation between the wind tunnel and the track is amazing," he said.
"Compared to my previous experience, it is something that has impressed me. Everything we take to the track ends up on the car, so it (the car) really does improve from race to race," added Smedley.