Team chairman Niki Lauda believes Mercedes is on track for the start of official 2014 Formula 1 testing, despite the huge challenge of the new turbo engine.Germany's Auto Motor und Sport reports that Red Bull's boss Christian Horner floated the idea of delaying testing until later in January 2014.Lauda said: "Nothing is being moved. Plans are going ahead for late January. The task is huge for everybody."'EVERYTHING STOPS'The report said the team was testing its new V6, the energy-recovery technology, gearbox and cooling systems in a hybrid chassis on a test bench.Lauda admitted that cooling the 2014 package was one of the greatest challenges: "We are constantly learning new things. Suddenly you are managing things like water pressure and intercooling. Oil and water must be at a precise temperature window. Once you go just a few degrees above a certain limit, everything stops (working)."Lauda said he sympathised with customer teams which, unlike full works teams such as Mercedes and Ferrari, were unable to do "any comparison testing"."They are doing their cooling (development) only on the basis of information provided by the engine partner." He thought Mercedes and Renault, each with three non-works customers, had a slight advantage over Ferrari which was only supplying engines to Sauber and Marussia for 2014.Lauda said: "Four teams is four sources of information. Everybody is having individual problems so we can learn faster and respond sooner."