Bigger turbo for a diesel?

Question

if i were to put a larger turbo on a 4bt cummins diesel, will that affect my fuel economy?? if so, what would the possible changes be? i'm looking to add a little power and some fuel economy.

Answer 1

believe it or not a smaller turbo has a greater impact on the engine than a larger one, that is hoe it was explained to me.  

Answer 2

2 things.

1.with higher pressure resulting from a bigger turbo you will need to re program the computer to add more fuel , or you will burn off the engine.

2. now days , its easier to add a new brain rather then replace the turbo (as long as your not looking for more then 50-100 more hp)