Boost Dump Valve issues

I have been banging my head on boost control and BDV setup.

That turbo is very responsive and I had lots of problems with overboosting. 
I tried using closed loop control and could not get that working.
After I switched to open loop it was much easier to dial in.
I worked from full boost turning it down more and more many times to get a handle on it.
It seems it would have been easier to start with no boost and turn it up than it was to find all the spots it over boosts and get it turned down.

Whatever, I have it under control now but have run into issues with the BDV opening under part throttle and Fluttering.

The BDV got moved from the pipe between the TB and the cooler to the charge pipe between the turbo and the cooler.
This violates Greddy's instructions for the FV, I'd like to understand the difference and wonder if this may be the cause of the flutter.
Turning up the spring pressure doesnt stop the flutter, it moves it up pressure wise.
This seems like treating the symptom rather than the cause.
I thought of trying a delay valve or some other bandaid because it seems counter productive to turn up the spring pressure if it holds at WFO.
Is the control system the booger, or pressure waves bouncing back from the intercooler volume?

Any thoughts? Im perfectly happy to move the valve back to the other pipe on the outlet of the cooler as this seems the most logical place for it.
The move was done by another and I don't know why or what led to moving it.
I've had other internet experts tell me it should be located closest to the boost source, but then,
When the BDV opens the flow in the intercooler has to reverse (which I think may be the cause of the flutter).

The Greddy instructions are vague on how to set the valve, 

"If irregular idle or engine stall occurs, loosen the M6 lock nut and turn the adjustment screw to
HARD until the problem is eliminated.
After the adjustment, tighten the lock nut to secure the setting.
※ The adjustment is preset to the softest position form factory. Do not turn it further out that
this position.
※ Make sure to loosen the lock nut before making adjustment. turning the adjusting screw
without loosening the lock nut will strip out the top housing.
※ Then the adjustment screw is turned in, the stock of the valve decreases. Screwing it in too
far will affect the proper operation of the valve."

Those instructions might be easier to read in Japanese!

I thought it should be simply set to a couple pounds over full normal boost. Checked by applying a regulated air pressure against it.
But that would be influenced by the pressure signal received from the intake manifold. 

Learn me?

What part of the intake manifold are you getting your vacuum/boost reference from?  If it's really close to the valves or the throttle body, my first thought would be to try moving it somewhere with less pulses/weird E36 M3 going on.

This flutter is under acceleration, right?  I would expect it to flutter a bit moving from WOT down to partial throttle, as long as it doesn't impact the way it drives I wouldn't worry about it.

You could also remove and cap it off entirely to make sure your issue isn't in the wastegate or something- running without it shouldn't hurt anything short term.

Thanks.

The valve holds at WFO @ 21#. I'm seeing flutter at freeway cruise, lifting ever so slightly causes the valve to open. Its like the valve is too sensitive. In my eyes the valve should not open unless you drop the throttle significantly. Yes the flutter causes a surge of sorts, this is what is irritating.

Maybe I just need to crank up the BDV spring more? Greddy isn't clear on what to look for when adjusting. I turned it up some and that pushed the flutter up mostly out of the normal driving zone but its still right on the edge and easy to trigger.

I'm afraid that turning it up too much will blow off a hose. I'm thinking maybe a vacuum delay valve on the signal line? Or an orifice?

Manifold connection for the BDV is the same port the shared with the boost gauge (right next to the port for the MAP sensor) in the middle of the plenum.

Maybe it is because of the Hybrid turbo and the exhaust housing is too small causing too much part throttle boost?  Its a T3 5 bolt exhaust flange with an ATP 3" Vband adapter, the compressor is a Garrett 409080-5009 which I am told is a T4. It will bury the stock boost gauge easily!

In that case I would crank up the spring until you get some chatter from the compressor when you close the throttle fully, then back it off a bit.  If your hoses blow off you should probably address that anyway, you should be able to run entirely without it and not blow anything apart.

It has not blown off a charge hose, it did blow off the MAP hose once because it did not have a barbed fitting.