Clogged Exhaust

[willelvs]

I've been running though the forums like crazy trying to figure out what the heck is wrong with my car and why it won't build boost. I saw in one post that a person disconnected their down pipe from the O2 housing. Is that safe to do check to see if your exhaust is clogged? I don't want to drive it like that but I'm not building boost and just put a freshly rebuilt evo 3 16g on it and still no boost. One thing I notice when I'm going through the revs, that past like 3k it kinda slows down in rpm climb like the exhaust is clogged. I had a shop do a diagnostics check on it and they said that there was restrictive exhaust flow as well but they told me it was my turbo. I strongly believe I have a cat even though the shop told me it was a resonator (pics tomorrow). The previous turbo was an ebay special so I kinda believed them too even though the turbo had no shaft play and spun freely. It's got me in a slump cause I miss my power . Another thing I'm going to check is the MBC I have. I figure if it's not working properly the waste gate would still work on factory specs but still nothing. I'm pretty sure there is no way it would make the waste gate open lower than factory spec either. For people saying boost leak forget about it there is none. Engine runs great and idles no problem, 20inhg at idle and maybe 1 or 2psi at wot. Also I'm not too familiar with the PCV valve, I understand what it does but would a bad one cause maybe my BOV to stay open and that be my problem?

 

[primo513]

I havent personally heard of a clogged exhaust system but im sure it can happen. do you have a wg actuator with your 16g or do you have an external wg? maybe its stuck open. If it was your MBC then you would most likely have infinite boost because what the mbc does is cause a small leak to allow more boost to build until the mbc closes at your set psi. the pcv (positive crankcase ventilation) relieves pressure from the crankcase and sends it back into the intake mani. I would have the wg checked out

 

[shakeandbake]

When I saw this I thought of a banana in the tail pipe. But in all seriousness I agree with the wg idea.

 

[willelvs]

Update: So after removing the down pipe and running the car my boost magically came back. I have a clog somewhere in the exhaust and I'm betting it's the cat. Thanks for the help guys!

 

[RLSchwabe]

Update: So after removing the down pipe and running the car my boost magically came back. I have a clog somewhere in the exhaust and I'm betting it's the cat. Thanks for the help guys!

What did you end up doing with that clogged exhaust?