will a fuel ratio gauge show me when im in vacuum and when im in boost?teamxrsx said:well.....this depends on a lot of different variables. But mostly dependent on the persons driving techniques. If you drive around in boost(letting the turbo spool up) everywhere you go, which you will your first couple of weeks, You gas milage will suffer greatly. If you drive around in vacuum as much as possiable(depending on the turbo you choose and the manufacturer, this differs from setup-setup) You will see close to stock numbers, sometimes even better. Extreme's in weather can make a difference as well. There is a lot that can change the overall outcome.