My 05 JDM Sti was mapped to 1.5 bar about a year ago with fuel cut at 1.6 bar. I noticed a couple of months ago it was only making about 1.35 bar and today only 1.2 bar. Just as it got to 1.2, there was a fluttering sound and it wouldn,t boost any higher. I think that the fluttering sound was the oe recirc dump valve not holding the target boost. Can anyone advise on a suitable uprated recirc, or could it be caused by something else? Thanks Steve.

 

Got a forge recirc on mine, recommended by Bob Rawle.

 

Found problem. When I changed a damaged vacuum hose I forgot the restrictor pill. Steve.