why am i
 

boosting 14psi and not 15?

3rd gear WOT


mods in sig. i prly need a tune right?

because boost is a measure of the resistance of airflow in your engine. so its the access that your engine can not use. when you do things like open up exhaust, or port a head your more efficiently moving air with your engine and the boost pressure will decrease.

and your restricted because you dont have a tune. the car is set up to be at 260/260 the boost just adjusts to that hp/tq. like if your in higher altitude youll have more boost because of the air density. its only from i believe like 11-15 psi....