The squad was one of several to run the 2009-style groove-less slick Bridgestones at Barcelona, and also used downforce levels equivalent to those that will apply next year, when the aerodynamic rules will be very different.
"In the morning we used the standard 2008 VJM01 with the 2008 grooved tyres to establish a baseline set-up, but in the afternoon we moved to the 2009 downforce level and tyres," said the team's technical boss Mike Gascoyne.
"We obtained some useful information on their respective performance, and after a basic warm-up, the tyres behaved better than we expected.
"On longer runs there is some drop off with the 2009 tyres and there is still some work to do."
Test driver Tonio Liuzzi was entrusted with today's programme, and was cautiously optimistic - although he said the car's behaviour changed a lot when running with the 2009 package.
"It was difficult to drive as there is much less downforce, but I think Bridgestone has done a good job with the tyres as they performed very strongly over one lap," Liuzzi said.
"On longer runs it was not quite as good, but there is still a lot of time to get it right.
"I was pretty happy with the work we have done for both 2008 and 2009.
"It looks promising."
