Ok, so i've fited bailey dump valve and it doesn't work properly... the revs are jumping , and when i drive the car i can hear that it is not opening as there is no sound from valve but u can hear the turbo making that sq noise , which is means that the valve does not open at all....

I gave it to my m8 who has the same one , he swaped it to see if it is working on his car , and it is !!!!!

what the hell might be the reason.....

 

Try your mates on your car?
Get your mate to fit yours to your car?
You have plugged the hose that's no longer connected to anything?