i have a hks super dragger exhaust on my 04 wrx. there is a rather large hole in the flex pipe right after the header. would this be the problem for having low boost. im normally at around 18 but now im around 5. when idling the vacuum needle is at about 20. when i give it a little gas it goes to 15 then drops while im still giving it gas. then let go and it drops to 25 then back to 20.
Wow, it must sound awful too. My car just consumed the UP/turbo gasket after a track weekend. It sounded like a tractor, but still would build to 12-13 PSI boost (but very......very.......slo..o.....w..ly !)
For your boost to be that low it must be a gaping hole. Any leaks pre-turbo affect performance big time.
Glad to hear you're back in biz. My first UP failure was the flex section. I went with a solid pipe the second time and wonder if that's why the gasket failed. Could be that driving the snot out of it on track is a way of tracking down the weal link more quickly !