JEREZ, Spain - No team can be considered the favourite for the 2014 Formula 1 championship because the new V6 engines create far too much uncertainty, Red Bull principal Christian Horner said on Tuesday.Red Bull won the past four Constructors' and Drivers' titles but the regulations have changed dramatically since 2013 with a new V6 turbocharged engine and energy recovery systems replacing the old V8's.NO PREDICTIONSHorner told reporters after the presentation of his team's RB10 car at the Jerez circuit in southern Spain: "All bets are off. It's impossible to predict. I think the power unit's going to be a big element in this championship and only time will tell. Reliability is going to be key, the races are going to have a different look to them in terms of drivers' and teams' strategies, and because fuel economy is going to be critical."Although 10 of the 11 teams were in Jerez for the first pre-season test problems with the power units meant some of them put in few or no laps on Day 1. Red Bull's quadruple champion Sebastian Vettel spent a day kicking his heels as the Renault-powered team worked to fix a problem that surfaced overnight.'ENGINEERING CHALLENGE'Horner said it was an achievement in itself just to have a car at the track. "It's been epic this winter because the car's an awful lot more complicated, there's probably 40% more drawings required to produce it," he explained. "When you think we only started our crash-testing 10 days ago... thers have been doing that for several months."It's been a Herculean effort by every member of the team.".Horner said the new power unit "posed a fascinating engineering challenge" even if it had probably been introduced at the wrong time for teams facing a sharp rise in costs and a tough battle to secure sponsorship.Red Bull has a design genius in Adrian Newey, a master of aerodynamics, but Horner admitted that rule changes had taken away some of their advantage. "This by far is the biggest challenge we've faced, not so much aerodynamically but mechanically... the shift of emphasis is moving further from chassis to power unit."NEXT CHAMPION?Red Bull has a changed line-up, with Australian Daniel Ricciardo, 24, graduating from sister team Toro Rosso to replace his now-departed compatriot Mark Webber alongside Vettel. Horner suggested the ever-smiling Ricciardo could surprise a few people. "Daniel is a very fast young driver and he's been selected in the same way as Sebastian. He's a pretty cool operator and he' has tremendous natural speed."I think he could really pose a surprise on occasion this year. It's going to take him time to settle in and develop but the underlying fact is that he's extremely fast." Stay with Wheels24 for the 2014 F1 season – fresh reports every day.