ok so seriously odd boost issue, need help here, vacuum line from waste gate to jpipe (to troubleshoot this same problem, i eliminated the boost controller from the equation) on my evo 8, (evo 9 turbo that i just purchased) im in the midst of tuning. boost stays stuck at 12 psi until 5.5k then boosts up to 25 psi... ive tried 2 difft actuators... the only other thing i can think of is that i actually bought an 8 turbo and im just using the wrong actuator (evo 9 one)? anyone ever gone through this before?

 

The wrong wga will hit the j-pipe, not make boost creep. Sounds like the wastegate can't open as far as it needs to causing creep.
Put a compressor to the wga and slowly turn the pressure up. See how much travel you get.

 

When you floor it from 2500 RPM in 4th, by what RPM do you see 12 PSI?

 

The boost creep makes sense... Its just never done this with my original 8 turbo, or my fp black. How much boost should the stock evo 9 wga allow? Like 12 psi? it hits 12 psi by 3 k using straight spring pressure, then it creeps up and hits 25 psi by like 5.5k, I have a short power band (about 5k-7k) pretty frustrating

 

13 PSI of creep ain't normal. It's silly in fact. To the contrary, IX turbos are notorious for boost taper. So, that level of creep is way out of the ordinary.

 

Have you done a boost leak test?

 

You should see 1/4" of wga travel at minimum. As much as 1/2" but I think your WG flapper is either not opening at all or barely opening. You may need to remove some preload from it.

 

Did you ever figure this out? I have the same problem now. Took my boost controller off to break in my clutch, boost line directly from the Compressor housing tee to the WGA. Boost hits 12 psi fast, around 3k, and then around 5.5-6k it jumps up to 20-25. This is on a 10.5/20g setup.

 

I would do a boost leak test before you start chasing anything else down for sure.

How much preload is on the WGA?