JEREZ, Spain - Sauber showed off its new Formula 1 car on Sunday with German driver Adrian Sutil hungry for success after a winter of weight-watching.Sutil embarking on a fresh chapter after spending his career to date with Force India. He's one of the bigger drivers in a sport whose rule changes in 2014 favour lighter and smaller men more than ever.Sutil said: "Training is going on as usual but I'm more focused on losing weight. I'm a tall driver and was always on the weight limit but now I've to lose the last few kilos. I didn't eat too much over Christmas and New Year."LOAD SHEDDINGThe new turbocharged V6 engines and energy recovery systems are heavier than 2013's V8 and teams have found it a challenge to get the cars down to minimum weights. The heavier the driver, the more weight in the car and the greater the disadvantage because there is less ballast to distribute for balance.Sutil is 1.84m tall and weighs 77kg, Williams' little Brazilian Felipe Massa is 1.66m and weighs only 60kgSauber, which has Mexican Esteban Gutierrez as its spare race driver, had a financially fraught 2013 and struggled in the first half of that season before finishing strongly after Pirelli made tyre changes. Team principal Monisha Kaltenborn said the team had learned from the experience but refused to make any predictions.She did, however, say: "One thing's for sure: reliability will be of the essence, especially at the beginning of the season."The lines of the new car were more fluid than some others unveiled so far, with the low nose also appearing a more aesthetic solution.Chief designer Eric Gandelin said the car running in Jerez would lack some performance parts due to be added at the next two tests in Bahrain. Gandelin said: "This gives us time to maximise the development of these performance parts and we can run the car during the first test and check all the systems, which we feel is crucial, considering all the technical changes." Stay with Wheels24 for the 2014 F1 season – fresh reports every day.