Trig - What psi are you peaking at?

 

28 now, but i really started to notice the dip after 25psi or so.

 

try switching the dv from push to pull mode (flip the dv position so the dv piston face is pointing to the intake pipe) to determine if dv cracking is the cause. setting it to pull mode will 100% keep it shut under boost. doing this with the stock valve its a bit rough on the turbo during throttle lift, but ok to try briefly.

 

Good idea. This will help isolate the bov as the cause of the richness. After I measure the crack pressure and discover it is 25psi I may crush the little bugger.

 

My boost leak test showed that the stock IX BOV cracked at 25 psi. I crushed it 1/8" in a vice until the nipple was almost touching the top. It now holds 32 psi and I have no flutter at part throttle.

After reinstallation the mad rich dip in the AFR is gone, and the same goes for the lean peak immediately after max boost. I have not made any other changes to my set up so I know that a leaky IX BOV was the source of the problem.

 

Nice job. Not many stories on EvoM with a successful resolution.