Sebastian Vettel thinks he could be on to a winner after trading in Kate's Dirty Sister for a younger model, Luscious Liz.

The German Formula One driver, overall runner-up in the championship last year to Britain's Jenson Button, spoke lovingly of his new Red Bull car at the season-opening Bahrain Grand Prix Thursday.

"There's no real explanation behind it, we all sort of like the name," he told reporters when asked why he had chosen that moniker for the Renault-powered RB6.

"Hopefully she doesn't need a sister. I can tell you after a couple of races hopefully, or Monday would be even better," he grinned.

Vettel started last season in Australia with a car christened Kate.

However that one was smashed up in the opening race in Melbourne and replaced by Kate's Dirty Sister -- so named because it was quicker and more aggressive -- with which the 22-year-old went on to win four times.

"It's pretty unknown what is going to happen right now," added Vettel, whose team are one of at least four with reasonable hopes of contending for the title.

"It's not a big secret if you put your money on one of those four teams but four teams means eight drivers and I think all of the eight are in a position to win.

"Hopefully Luscious Liz will win."

Red Bull won the last three races of last year, with Australian Mark Webber victorious in Brazil, and Vettel starts the season every bit as fancied as returning compatriot and seven times champion Michael Schumacher.

Team principal Christian Horner said recently that Vettel was now a complete driver.

"Obviously I have a target in my life and the target is to be world champion," said Vettel. "If I reach that target one day then I think I will be more complete than I am now.

"I think I learned a lot last year. I think the whole team and myself are in a good position. Last year was the first time for me and the team that we were in a position to fight for big points, race wins, pole positions.

"But the key is now to prove that we deserve to be there and this is what we still have to do."

The team might have won the title last season with better reliability, and further concerns have been raised by pre-season testing glitches when the car had to stop on track a couple of times.

"I think we have a good car, winter testing has been good and we have never been as prepared as we are now. On the other hand...we don't know where we are. We think we are pretty up there, I think Ferrari looks extremely strong," said Vettel.

"On Saturday (in qualifying) we will find out who is strong and who is not."