Trulli forced to use old power steering at Suzuka

The Italian is unable to use the new system, which was introduced at July's Hungarian Grand Prix, because it cannot stand up to the steering load created at the Suzuka circuit.

"Unfortunately, here I have to use the old specification of power steering, which I don't like," Trulli told AUTOSPORT. "It's because the new one cannot take all of the force that you have on the track.

"So I am concerned. I would be more comfortable going in with something that I know works. But we have made some changes that might be better. We won't know until we test it, so I am cautious."

The Italian credited the change of power steering system with turning around his season. Since using it for the first time, his form has improved and in Singapore two weeks ago he was set to beat team-mate Heikki Kovalainen until he picked up a puncture after being hit by Jaime Alguersuari.

He admitted that only since Hungary has he been able to enjoy racing in F1 again.

"Since I had the new power steering, everything was different," he said. "I could enjoy driving and drive the car better.

"I could also work on the setup, something I'd never done before Hungary. So all in all, it made it a more positive season."