LONDON, England - Formula 1 should be pushing for even better fuel economy in 2015 rather than talking about “completely unrealistic” ways of changing the rules.That's the view of Mercedes' F1 technical head Paddy Lowe.The start of the 2014 season has been dominated by talk of tweaking the new rules to make cars louder and possibly relaxing the limit of 100kg of fuel per car per race - or making races shorter.International Automobile Federation president Jean Todt told reporters at the 2014 Bahrain GP that the governing body would seek to boost the noise of the new V6 turbo/hybrids but made it clear that little else would change.‘COMPLETELY UNREALISTIC’Todt said: "It seems Mercedes is stronger. I don't have the power to say 'let's slow them down'. If its cars are quicker than the rest I think it is a challenge for the other teams to catch up."Lowe liked the sound of that: "I think Jean has taken a very sensible line. There's been things talked about here and in past weeks that arecompletely unrealistic." Mercedes celebrated its third win in three races (Bahrain, Malaysia, Australia) and second successive 1-2.Lowe said: "The first suggestion was that we needed 110kg (of fuel). And then, has anyone realised that you couldn't fit 110kg into these cars? Ah, oh dear..."Oh, well. We'll make the races shorter. Can you imagine selling that concept to the public? It would be like saying we've decided that people aren't fit enough these days and marathons are only going to be 40km, not 41km."The messaging around cannot be contemplated. I hope all of that can be put behind us."Lowe said talk of drivers having to ease off and save fuel to make sure they finish the race was ridiculous. He pointed out that Lewis Hamilton, 2014 Bahrain GP winner, and team mate Nico Rosberg had been racing each other flat-out and had more than enough fuel in Malaysia.Some teams, such as Mercedes-powered Williams, reportedly even started in Malaysia with less than the 100kg allowed to save weight and boost performance.‘PERFECTLY JUDGED NUMBERS’Lowe said it made no sense for a sport that prides itself on cutting-edge technology and becoming more road relevant to mass automakers to water-down the challenge."F1 is about developing technology, setting stretched targets. I would say the 100kg for the race and per hour (flow rate) are perfectly judged numbers."If that's a stretch for other cars, it's a stretch they should be reaching for. The nature of F1 is to push technology to the limit. The idea of backing out of that for 2015 is absurd. "If anything the point of F1 should be to stretch it further. Maybe in 2015 it should be 95kg for the race."Stay with Wheels24 for the 2014 Chinese GP on April 20.