Toyota’s chassis chief Pascal Vasselon says the new TF108 is a departure from the team’s recent cars.

After making an apparent breakthrough in 2005, the Japanese manufacturer slipped back into the midfield in ’06 and ’07, and team principal Tadashi Yamashina recently admitted he has two years to convince the Toyota board that its investment in F1 is worthwhile.

To this end, Vasselon says his design team adopted a completely new aerodynamic approach with the TF108.

“I think it’s quite obvious the aerodynamic concept has changed,” he said at the launch of the new car in Cologne on Thursday.

“The TF107 was an evolution of the TF106; this new car is a departure from recent Toyotas.”

The new car features a longer wheelbase and more sharply undercut sidepods than the TF107 (designed to accelerate the air faster along the lower bodywork to the rear wing and thereby increase downforce).

Overall, Vasselon says the aim of the aero changes has been to achieve a more consistent balance and a larger ‘sweet spot’ than on the TF107, which had a narrow set-up window and was extremely sensitive to pitch and ride height changes over a lap.

“The aerodynamic philosophy is geared towards minimising aero and balance variations over the lap, thereby producing a more driveable and stable car,” he said.

“A fundamental change is the wheelbase, which is now longer.

“The main reason for this is to achieve more stability, but secondly we also expect greater aerodynamic development potential, giving our aerodynamicists wider surfaces and more space to play with.”

There have been more minor changes on the mechanical side because the team was happier with existing performance in this respect, although the TF108 does feature an all-new seamless-shift gearbox.

“In chassis and suspension terms, we felt we had a decent base so we’ve focused on making just a few refinements,” Vasselon said.

“Structurally we’ve worked on achieving similar stiffness with less weight, which was especially needed in the context of regulations which have added a few kilos to the car.”

Vasselon said the signs from wind tunnel testing have been encouraging, but admitted the team has a lot of work ahead of it to optimise the performance of the TF108 before the season-opening race on March 16.

“At Toyota we believe in setting aggressive, challenging targets so we aim high,” he said.

“It was quite straightforward to see where we could make improvements and what targets we should be aiming for.

“But setting targets is the easy part; the real challenge is to deliver performance on the track.

“Everyone has worked very hard to get to this stage but really the work is far from being complete.

“Now we will focus first on understanding the characteristics of the car on the track in order to steer set-up and development directions.

“There is a lot of work to do to get the most out of the car before the season starts so there will be no let-up in our efforts.”