i recently bought a dumpvalve for my 95 wrx classic which is shown in the pic below. i have folled instructions to fit it and all i seem to get is turbo chatter. the dumpvalve is fine as i heard it working on another scooby.
HELP lol or have i been completely retarded and fitted it wrong?

 

Depends on what boost you are running compared to the other car. If less you'll need a softer spring

 

Mines on about 0.8 bar ( 13-14 psi ) where can i get a softer dpring?

 

Should find one if you put in google the brand of it and dump valve spring. There's normally 2-3 springs depending on boost pressure. That chatter means the spring is for higher boost so its not opening on lift off so you're getting compressor surge