Rebooted Red Bull revved up and raring

LONDON - Red Bull is hoping Renault's revamped engine will give it the power to challenge champion Mercedes in a new-look Formula One championship this season.

"It's a brand new engine this year, a change of philosophy," team principal Christian Horner said on Monday.

"Renault had a big winter. We're hoping for a step up in performance, and then hopefully we can really give Mercedes and Ferrari a hard time."