I just bought my first diesel truck, a 08 f-350. How much boost should I have? I can't get it over 22. It is completely stock.

 

What are you trying to do with it? Mine pretty much lived between 10 and 20 for normal daily driving (around 15). But when my 5th wheel was hitched up, on a flat highway it would stay right around 20, and when I hit the hills, it would head up to the mid 20's. Bigger hills would push it over 30. So it depends on what you are doing.

Keep in mind the more boost, the less gas mileage. So you want the lower boost anyway. Unless it's needed.