I just changed turbo for MY01 which is VF34, but these days I cannot heard
any sounds from my dump valve(Forge VTA), so do you think I need change dump valve spring , what's colour is better and where can I find them , thanks.

 

btt

 

Eh? Do you want to tell us more about exactly what you've done here?

What exact model of car do you have and what exactly did you do? If you took the TD04 turbo out of an otherwise standard MY01 WRX and dropped a VF34 in with no other work done, the dumpvalve at this point is the least of your worries.

If this is the case, are you monitoring boost pressure, AFR and knock?

If you have an MY01 Japanese import STi and swapped a broken VF34 for another (good) one, if the dumpvalve isn't working, that would indicate that your surgery under the bonnet was incomplete/erroneous in some way.

 

o my car is UK New Age My01, it changed HKS Air fliter and Full decat, noting more,
these days I have change a VF34, then I cannot heard any sound from dump valve,
the boost pressure is 12psi, any idea?

 

btt