Ok so here is the situation:

I've got a turbotoyota setup, 38mm tial wastegate with a 10psi (big yellow spring). Everytime I floor the gas pedal, it starts to build boost but just hangs on at 5psi. I've taken it to near redline still stuck at 5psi.

Boost leak? Checked that out with a boost leak tester. None.
Faulty/knock off wastegate?
Faulty BOV? (I've got a Forge BOV)

So I put on a manual boost controller. BAM! I hit 10psi.

So whats up with that? Anyone ran into similar situations?

 

How is you vac line run? To you have a Tial wastegate? If you do use the side port only off of a vac source, if you do this don't use a boost controller.

 

I use the side port. If I use the boost controller then this is how the vac line is like:

turbo compressor->boost controller->side port of tial wastegate

I ran like this and it held boost. Take it off and no boost.

The Forge BOV was in hybrid mode 50 atmospheric and 50 recirculate. Maybe that's the problem...hmmm I'll have to try it either in full atmospheric or recirculate.

 

its not the bov. where is your vac line tapped to the car?

 

With the wastegate run a Vac line from the side port directly to a vac source off of the intake manifold.