How can I change to opening preasure of the TIAL wastegate from 0.45 Bar to something higher like 0.7 or 0.8 Bar.

I´ve heard with a different spring or so. Or can I put a kind of plate between the spring and the piston?

 

you can get a variety of different springs, or just use a boost controller, which will aid in spool up as well as boost control

 

concurred. Keep the .45 spring and get a boost controller, preferably electronic if you have the $$$

 

I have the Apeci AFC-R boost controler, but the magnetic switch must not work as hard when there is a spring for 0.7 Bar. I thought