Okay, so I have been looking all around online to see whether or not a turbo can increase your MPG(Km/L). I have seen people saying that they not only got more power but their tanks lasted longer, but that's not very reliable seeing as my weekly MPG changes all the time even just going the same route. I've also seen people saying that it decreases your MPG due to the fact that it's forcing more air in, meaning the engine still needs to use more fuel to meet the mixture ratio. I have also seen people saying that technically your vehicle becomes more fuel efficient because it's reusing the exhaust to generate more power, but that just relates to your emissions and relating to more power for less emissions. I have also read that there are "turbos" that wont neccisarily give you a performance boost but actually are built to increase you MPG, but I haven't been able to find anything to support that or what the difference is between the turbos.
What do you guys think? Have any of you found an actual article relating to testing the vehicle with and without a turbo and showing the increase in power, decrease in emissions, and MPG change? I've been searching for quite some time.