I did searches and have read people saying that a boost contoller can't lower boost, only raise it.
And now I am confused

Theoretical:

OK, . I have a boost controller and sometimes I want to run 8psi and sometimes 12psi(such as an APEXI ACV with Hi and Lo settings). If the wastegate is big enough to let enough gas out to lower it to 8 psi then why wouldn't it work?

I think I understand the concept: You can't lower boost if the wastegate can't escape enough gas to lower the boost to that level. Thus, giving you a limit to how much boost can be lowered based of the effectiveness of the wastegate.

So, If I have a big wastegate, why can't I lower boost from 12psi to 8psi?
or does all of this just pertain to the stock wastegate which is barely adequate?

Tanks guys(and the few gals)

 

Hmm, what does the wastegate spring do?

 

the reason why you can't run 8 psi on a BIG wastegate is because most of the aftermarket wastegate springs are 10 psi. Now, you can turn your boost controller up and turn it down but it just won't go lower then 10psi. depending on your wastegate spring or you can even turn off your boost controller and it will still be at 10psi because of your set spring in your wastegate. hope this helps