For the most power and best spool, remove downpipe from turbo. This will get backpressure as low as possible.

So no, an exhaust leak after the turbo does not explain your problem. See my other post for what to check/look for.

Update:

So I just had time to look at my downpipe and its fully connected. It just looks off.

When I was under the car, I was tapping around and noticed that my cat has a rattling noise (you can hear this when you drive too). I'm guessing my car went bad-- but I've only had it installed for less than 5k km (FM cat). I've heard when you run the car rich you can ruin the cat, but the only time the car is extremely rich is under boost (10.5-11ish).

Could a clogged cat cause the symptoms I'm finding? My car smells like gas and won't boost past 3PSI. I also find it hard to drive it past 100km/h as it'll rev up to 4-5k RPM but I can hear a huge "pshhhhhhh" -- leak noise (not boost).

I've looked for boost leak and haven't found anything to support that hypothesis yet.

Can this be explained by a clogged cat?

Yes, a cat would cause that. The exhaust is highly restricted by the clogged/broken cat, so you get a lot of back pressure. This means it runs rich, which is why you're smelling fuel, and it limits power and turbine spool.

FM was selling metal-core cats for a long time, but they had a lot of in-warranty failures on them, so they have since been replaced by ceramic-core ones. These are more restrictive, but have longer life.

--Ian

Any idea if FM offers a warranty on the Magnaflow cats they sell? I guess I'll give them a ring and see what they can do.

I'll post up the results once I remove the cat and test the car.

It probably does, although it may have expired. Definitely give them a call and ask.

--Ian

Why so rich? Seems most folks run 11.5 - 11.8 at most.

See post 3 in this thread.

Update:

It's not the cat. I pulled it and drove without it. Same old power loss.

I've fabbed up a boost leak tester and found that a leak is happening where the IAT inserts into the silicon pipe (FM2 kit- 2015). The leak is happening from the conduit from which the IAT mounts into on the silicon pipe. So I've thrown on RTV around it to hopefully cover the boost leak. I'll update when I get to drive it.

silicone coupler + rtv + metal sensor sounds like the biggest bucket of failure this week

For a factory VVT motor I think your compression is dogshit