This problem has been haunting my build for the last two years, and I dont know what else to do.
The problem is while boosting at WOT or really any throttle after about 15psi the boost starts fluttering like crazy, i'm getting very bored running around at 15psi.
d16z6, trying to fix this problem I practically put a brand new turbo setup on it besides the turbo and engine itself, NEW
from stock to skunk2IM
from stock to 65mmTB
from ebay kit to all mandrel bent pipe and welded by me Charge piping
went from HKS knockoff to tial BOV
went from china crackie chan mani to SPA topmount cast manifold
went from china wastegate to turbonetics deltagate
I'm using a t3 turbine .63, and a TO4E .70 compressor housing (not exactly sure what trim wheel .57 I think)
The only thing I can think of is that with both of my setups I have been using a low pressure spring in the wastegate, like 6-8psi springs. Boost starts to build nice and solid but as it reaches time for the wastegate to open it flutters, sometimes the wastegate opens and boost stabilizes, other times it just keeps fluttering. I am getting very pissed. AFR's are good and adding timing seems to help it a LITTLE bit but doesnt cure the problem. Please help!