You dont HAVE to run a dump valve on a cossie unless it is running a T4 turbo or higher.


On that boost, 22psi, running no dump valve wont cause any damage TBH

I ran a T3 at 27psi with no dumpvalve for over 8k mile. Took the turbo off and it was fine.

As for chatter, just take the dumpvalve off, block it up and away you go