Downpipe on stock S5 turbo...overboost?
 

I bought a 2.5" bonez downpipe a while ago and haven't installed it yet. My S5 TII is all stock except for an Apexi Power intake and Apexi dual N1s. My car is going up in the air on Saturday for a tranny swap so I was thinking of installing it at the same time. I'm guessing my turbo will "breathe" better and boost harder, but will it too much? According to service records, about 40k ago the fuel pump was replaced with a cosmo pump (no idea if it's the 13B one or the 20B one). I was originally planning on waiting til I put in a new turbo, but who knows when I'll get to doing that. So, turbo experts, what do you think. Leave my old ass precat on? Or put on my shiny new downpipe?

oh right and I also have a Bonez HF cat I was planning to use to replace my old one.

Don't know about the boosting, but that is a nice durable cat.

are you still using the stock t.i.d?

Install it all and watch the boost......simple. If its going nuts you'll need to adress the problem and port the wastegate, or add more restriction to the system (not the best idea though)

FWIW, I had a 3" bonez cat on my TII and blew that shit apart on the dragon after roughly 2500kms of break-in driving, and 500 or so beating its ass up. Would never pay that much for a cat again in my life.

Different over here but get rid of the cat entirely if your emission law allows. You will get boost creep so you will have to be careful. You could port the wastegate a bit as that will help stop this.

TID? I forget what that stands for, but everything is stock so I'd say yes.

Turbo inlet duct.