Frentzen Still Puzzled by Ferrari Engines

German driver Heinz-Harald Frentzen has questioned characteristics of Ferrari's Formula One engines while stopping short of accusing the Italian manufacturer of breaking any rules.

Frentzen suggested last week that the Ferrari-powered Sauber team used some sort of traction control during this year's Australian Grand Prix, and though he still believes the Italian engines use a system to stop to wheels from spinning, Frentzen admitted Nick Heidfeld was not to blame.

Heidfeld, who finished the race in fourth place, kept Frentzen at bay during the final laps of the race.

"In the past 18 races, I had plenty of opportunity to trail behind Ferrari cars or machinery powered by Ferrari engines," he said on his website.

"And one thing was particularly remarkable: out of tight corners, these cars had a pretty stunning acceleration, combined with a misfiring engine.

"For me, it is beyond doubt that somehow Ferrari managed to develop an engine software which reduces the power by a certain margin to the extent that the driven wheels don't spin.

"It cannot be ignored that something like that exists, there is simply no room for discussion about that," he wrote.

"On the other hand, however, you can discuss if the device that exists is legal or illegal. I believe that Formula One - thanks to its brilliant engineers -- progressed into an area which is hard to be defined even by the FIA.

"In the laps when I was following Nick (Heidfeld), he drove without any errors. This was a performance that deserved to be awarded with his first ever Formula One points."

Traction control has been banned in Formula One since the end of the 1993 season but is being allowed back by the International Automobile Federation (FIA) from the Spanish Grand Prix at the end of April.

One of the reasons why it is returning is because the FIA admits it has been impossible to police properly.