BAR faces decision on new Honda

The Canadian said that the new engine was faster than its predecessor, leaving question marks as to which engine the team will choose to run in Melbourne. Villenueve's quandary has been compounded by the fact that he only completed 17 laps in the car today after suffering from a run of mechanical failures that prevented him from setting a lap-time until 2pm this afternoon.

"Today I didn't do many laps but from what I did I can say that the new engine is better on power, but it's heavier so it has a negative effect on the chassis," Villeneuve told autosport.com. "We have to decide which engine we'll use in Melbourne, so hopefully I'll do more laps tomorrow so that I can decide then."

Comparing the new engine to the old one, Villeneuve said: "It was less driveable. This is okay. The new engine is not bad, but we have to decide tomorrow after doing a few more laps. I can't decide at the moment."

One factor that could impact on Villeneuve's decision is the poor reliability of the new car, which the team reckon could be down to bad vibrations. The heavier engine would likely increase the vibrations the car is suffering from, and cause more reliability problems.

Villeneuve will have one final day of running for the team at the circuit tomorrow. Team-mate Jenson Button was due to take over from the Canadian this afternoon, but is side-lined with the 'flu.