23psi stock tsi, wastegate or?

[phase17]

I have a 1991 Talon TSi. Only mods are BSC restrictor removed. I had a boost gauge hooked up and it read 15psi consitently for quite some time. Well it broke so I drove without it for a while. In that time I used a datalogger and messed with getting my base timing correct. Today I hooked up my friends boost gauge to see how things looked and I was pushing 23psi. The first WOT it topped out at 15psi like before, but as I kept driving boost kept increasing until it was at 23psi. The car accelerated slower each time as well. I searched and figured it must be the wastegate. I read that if I run a hose from the jpipe to the wastegate only and boost exceeded 7-8psi then it was bad. Well it went to 23 just like before. So overall I just want to know if this sounds like it's definitely my wastegate, or if something else could be causing the issue.

 

[KazooGS-T]

The boost spikes, could be from the vacuum line on your wastegate either being off or leaking. It also sounds like a sort of boost leak you are having. What is your vacuum source from your boost gauge based on, and check the lines on the mbc.

 

[phase17]

The lines are attached, but I didn't inspect for leaks, they do look crummy. I'm not sure what you mean by vacuum source for boost gauge, like what line is it tapped into. I did the FPS line, and when I had the BCS disconnected I tapped into the P line off the throttle body. Both lines gave same results.

 

[Mr Peepers]

What you are describing is boost creep, when the wastegate can't bypass enough exhaust gases around the turbine to maintain a constant boost pressure. I would check if your wastegate flapper is getting stuck in its travel. 23 psi is definitely not good on your stock fuel system, and consequently engine. Make sure all lines leading to the wastegate are not leaking just to rule out a possibility. You can port the o2 housing and turbo to help with boost creep if nothing else solves the problem; there are many threads on this subject.