Tried searching and nothing proved to be helpful, so I am sorry if this is a repost.

I have a stock B18B which I just turbocharged with a 14b turbo. The kit is homemade, turbo was bought used. The turbo has no shaft play and I was told by a friend who is deeply into DSMs that it is in great condition (not the same person I bought it from). I got the car up and running and it is running great except it will only build a max of 5 psi. More often it will only build about 4.5 psi with the occasional spike to 5 psi.

I started looking for leaks, compression tested all of the IC piping up to about 10 psi. Everything checked out fine with the exception of a smalls leak from the compressor housing (I can post of a picture of where it is). But the leak is not big and will drain about 10psi in 15-20 seconds which I am told is not serious enough to not be getting full boost although I should fix it eventually.

I have a short log manifold so it is easy to feel any pre turbo exhaust leaks and there are none.

Since the IC piping checked out, I was told to check if the wastegate is good by plugging the wastegate vacuum hose and see if it will continue building boost and build boost quicker. So I plugged up the wastegate vacuum hose and the turbo spools quicker and will spool up to 10 psi at which point the stock MAP sensor gets angry and the ECU cuts fuel. So that would mean the wastegate is working properly, right?

What is the next step in my troubleshooting? Has anyone else had and fixed this problem?

Thank you ahead of time!

P.S. I have Hondata S300 so I can provide datalogs if that would help.

 

ttt

 

Are you using a boost controller.. if so what kind? and how do you have your vaccum lines hooked up?

 

No boost controller, just the stock internal wastegate with a vacuum line running from the wastegate actuator to right after the compressor exit.

 

ok well a stock 14b wastegate actuator should open at about 9 psi when hooked up directly. im think that since you checked for vacuum leaks and have none that maybe you wastegate actuator is bad.