boost issues

[Boos929]

my car wont hold boost will boost up to 14 psi by 4k and then drops down to 10psi by redline and another thing I noticed is if i go from a stop it will only boost like 11 psi but if im cruising at like 2500 or 3k and get on it it will boost 15 psi then of course drop off to 10 running stock turbo and wg herd people saying to shim the wastegate what does that entail new to this stuff just finally getting done fixing everything and all the maitenence but cant figure out this issue

 

[Furbasher]

This is a pretty vague question. Do you have a MBC or is everything factory? Turbos tend to spike and then settle when building boost but 4psi seems excessive.
Also I can imagine the 14b turbo would sort of run out around 4500rpms. Could be wrong though.

 

[Boos929]

Yes I have a mbc basically stock everything else tho

 

[JCorbo25]

When was the last time you inspected your turbos wastegate? If it's an old 14B, it could be cracking around the wastegate flapper and having trouble holding boost up top.

How is your MBC hooked up?

 

[Boos929]

One line hooked into waste gate other hooked into intercooler line I believe is how it's hooked up