Quote:
Originally Posted by rjdnyy224
that's kind of what I was thinking. I know compressor surge is no good, but that's the flutter you hear on supras and the like. if the DV+ causes this, then I'm definitely going to avoid it. but if not, like you asked, where is this flutter coming from? what valve, the diverter valve?
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Quote:
Originally Posted by lonecitizenfour
Where does the valve flutter come from? That noise sounds exactly like compressor surge... is there another part that is a fan somewhere and has air hitting from the blowing side (i mean even if that's not turbo, it can't be good no?)
Thanks
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Again, I'll say that this is not compressor surge. This is diverter valve flutter. What happens is when you release off the throttle at let's say 50 to 75% and it flutters, the boost is escaping, but because of the pressure changes and one hole, it flutters as it rapidly changes. This also GFB's intention of how their DV's work in general. When you rebuild the system, in addition to the reduced number of holes, you also put in a stiffer spring. This is to ensure that only enough boost gets out that is needed to PREVENT compressor surge. Their intention of doing this is so that you can retain as much boost as you can without hurting the turbo, which is why you get great throttle response with their DV+.
TLDR: Fluttering at low RPM is perfectly normal with a DV+. This is NOT compressor surge and is simply the stiffer spring allowing only the amount of boost out needed to prevent compressor surge. If you get this at full throttle or full throttle liftoff/high rpm liftoff, then you might want to ensure it was installed correctly.