logic this out with me....
my turbo is not building boost, or, building very little. And quite high in the RPM range.
There is not leak in the exhaust feeding the turbo. Wastegate is sealed.
No vacuum leaks (which would be boost leaks).
I’m running lots of timing to help spool and it’s more than fat on the AFR side.

What can cause this?
My engine should be plenty capable of spooling this turbo. Sorry, I don’t have the details on the exhaust side.

I’ve got plenty of spring pressure on the BOV, so I’m confident it is not leaking.

 

Wastegate fire ring in place?

 

Have you tried pulling timing? It sounds backwards, and it won't run as clean, but should put more heat and energy in the exhaust. Something to try.

 

Fire ring is in place... it was leaking a bit, so I pulled the WG off and had a look. There was a very small piece of aluminum keeping it open a bit. Cleaned off and reinstalled.

When I ran this turbo, initially... I had 5* base and it built 6 psi boost.
Now, I’m at 15* base.
So, you think maybe I should pull timing? I’ll try it today.

 

If you had a gate issue I would definitely test that first, I was thinking of timing as more of a troubleshooting tool.

 

I’ve placed tape on the WG to see if it is leaking... doesn’t not break the tape or burn it. So, I’ll say that it is working as it should.

 

Backed the timing off... only see 6 psi, on the shift to 3rd and at full throttle.

 

Any chance your blow off valve is open?

 

So you have never seen more than 6 psi with this combo?
You don't know the details of the exhaust side but your "engine should be plenty capable of spooling this turbo"?
Need to check the size of your hot side vs size of the engine and rpm plus things like length of hot side plumbing etc etc.

 

I’ve no more problem building boost.
I can’t remember which turbo I was asking about... I thing it was the BMW one. I have the turbine wheel measurements somewhere, but have no idea what the AR is.

Anyway, I’ve swapped in a correctly sized turbo for my application and holy hell! What a difference!
Easily seeing 20 psi!

 

That's great!
I know how it feels when you move from a turbine that's way too big to one that's just right!