An Interesting boost problem
 

I haven't heard of this problem before but last night I lost my primary turbo. I pulled out to pass some traffic on the motorway and I had no boost till I hit 4500rpm, and then it only hit about 0.4 bar.
I had dig through the vac hoses tonight and replaced 1 hose with a split. There may be more in there, I only replaced them about 4 months ago with silicone. All I have on the car is an exhaust and a PFC and a Blitz dump valve.
I checked the turbo control actuator, as this was my problem last time. The circlip is still on the arm and the arm is out at Idle, which is where I think it should be.
Checked all the large diameter hoses and likely places for a boost leak and nothing.
I don't think the primary is spooling up at all. What is likely to cause that?

Any suggestions?

What do you mean by saying that you have exhaust? If you just mean catback, then if you have no other leaks, it could be that either downpipe or main cat got clogged.

Amel

It is a JDM car so I have no pre-cat. I have new decat and a new Cat back on the car.

It is a JDM car so I have no pre-cat. I have new decat and a new Cat back on the car.

I had a similar problem. I would make a little boost 4-6psi then 0 below the 4500 switch and then it would slowy rise to 5or7. It turned out to be my primary intake hose crunching in. Hard pipes did the trick. I hope that you didn't lose your turbo:(

had same thing happen to me once, replaced primary intake hose also and problem was solved, grab the hose, if it is real soft then chances are that could be it. btw I got a new hose from the dealer and they are pretty hard.