Turbo "flutter" has increased

[Alex O]

I wonder if anyone has an idea about this?:

When you stand at the rear of the car there is a black canister, bit like a coke can, that has various vacuum pipes coming out of it.

One of these came off under boost a few weeks ago. It's back on with a zip tie added but since then I get much more fluttering noise.

I have an HKS SSQV. Even if I change gear at very high revs, full boost I can hear a flutter with the standard sqeek/sneeze noise.

Thoughts? Could the SSQV not be opening fully?
Thanks
Alex

[JJ]

Dump valve adjustable ?!?

The flutter can be compressor flutter which is caused by a dump valve closing too early... retaining charge in the pipes...

[h20490]

I alway thought that the jdm bovs ie HKS and Blitz have harder springs so are more suited to higher boost so if your at standard boost or at 1.0 it flutters as it doesnt release as quick.

but a cheap forge one has a lighter spring and vents quicker??

probably talking crap but thats my take on it

[Alex O]

Dump valve adjustable ?!?

The flutter can be compressor flutter which is caused by a dump valve closing too early... retaining charge in the pipes...

I think my HKS is a version 3 and am pretty sure it can't be adjusted.

Been on the car for 4 years or so but things changed when the vac pipe popped off.

Car doesn't seem to lack any performance, just wondering if its bad?

[Ethan21]

It will be the dump valve, happen to me with ssqv 2, changed it to a ssqv 4 copy and no longer have any issues

I think the problem is they start not to open enough

[JJ]

I had a HKS dump valve that went bad on me.. just stopped dumping... so the compressor would be fluttering against the throttle shutting and the dump valve not opening...