Ok so, about 3-4 days ago I noticed that in WOT I could only get 7-8psi, I've had the car set to do 12-13 with the Prosport MBC for months now.

I looked around under the hood to look for a vacuum line leak or any boost leak from the couplers, all seem well. The charge piping that goes into the turbo, has a flat spot but it should still seal properly when clamped on ( i think)

While I was diagnosing that, I saw that my DP is only on by one bolt and all of the other has sheared off. So I had to take out the manifold/turbo and used an extractor to get the broken bit out. After all of that is done, I put everything back together and drove the car and now the car is getting barely 10psi

I used a compressor and a makeshift boost leak tester to check it under pressure. The compressor cover where it meets the turbo looks like it was leaking a bit, as well as the bolt for the throttle cable( where the spring is on the tb)

What do you guys think it can be?

Is my MBC bad? I've tried adjusting it and nothing happens
Would that little flat spot/ovalling on the charge pipe has this much effect?

 

when does it make 10psi? at redline?

what is your wastegate pressure?

leaking BOV?

 

not redline,just at wot at around 5-6k when i usually see full boost


i believe i have a 7lb spring in there

we checked the bov when we did the boost leak test and it was fine. Unless theres another way to check it?

 

Bump?

 

The issue with the charge piping wouldnt cause this issue. This is going to be one of a few things:

1. Bad boost controller
2. Leaky wastegate
3. Boost leak
4. Turbo is shot and can't spin fast enough to make sufficient boost
5. Bad signal to the wastegate/MBC

 

agree with post above

and

remove the mbc and see what happens. if it goes to gate pressure perfectly and runs right i would see what happens with another mbc, it sounds suspect and would be a good place to go after you look over the fittings

 

I'll run the turbo straight to the WG and see if it hits spring pressure tomorrow

How would I check for a leaky wastegate?

Also, how can i check if the turbo is shot? It's a brand new bought 5431B and is maybe 4000 miles old. Zero shaft play, no oil anywhere.

What do you mean by signal to the wg/mbc?

 

bump

 

means the vacuum