Walker has been getting to grips with the 2008 World Series car

The new model is based on the 2007 Renault Formula One car but has a new front wing, side pods and the V6 engine now develops 500 brake horsepower.

"The new car feels great and I'm really looking forward to getting stuck in now," Walker said.

In February Walker decided to stay with the Fortec team for the 2008 World Series after pondering a move away.

The World Series is seen as a stepping stone to Formula One, with drivers including Fernando Alonso and Robert Kubica having previously raced in the championship.

Each car in the championship is identical so it is a true test of driver skill, although each team only had one car to test in Valencia, meaning Walker had to share his time at the wheel.

"It was really a shakedown for us so we could get a feel for the new car and be ready to hit the ground running at the next test in Barcelona," Walker said.

All the World Series teams will head to the Catalan capital in early April for a three-day testing event where the drivers will be able to get a proper feel for how the new car drives.