Big fan here! I'm looking to buy a new car this year and I was wondering which vehicle is more fuel efficient. Is it the Chevrolet Cruze with manual transmission or the Ford Fiesta with automatic transmission?
Weight is the enemy of performance, efficiency and low fuel consumption.
The Chevrolet Cruze is very heavy. When BRE Racing Team Principal Francisco "Pacho" Blanco was preparing the production-class Cruze touring car, significant performance was gained when they stripped off all the sound-deadening material. This foam-like substance helps keep high-frequency NVH (noise, vibration, harshness) absent inside the car, making for a smooth and leisurely drive but obviously weighs the proverbial ton.
The Ford Fiesta is smaller and lighter than the Cruze and despite having a 1.6 liter engine with a twin-clutch transmission, it has the potential for greater fuel economy and efficiency because it enjoys a better power-to-weight ratio than the heavier Cruze. A good way to look at it is a big carrying a 100kg sack of rice, versus a small guy carrying the same 100kg sack of rice. Who will get tired easier? The smaller guy because he is exerting more energy to carry the same weight. And exerting more energy and effort means consuming more resources, and in your car's case, more fuel for the engine.
In city driving, where we accelerate and brake quickly almost all of the time, a lightweight car, matched to a torquey engine wins the efficiency race. Hope this helps give you a better idea of how things really work in the real world, versus spec-sheet racing and bench-racing.
So tell us what you think! Good luck, God bless and keep it safe out there.