Routing your
Bypass Valve back into the Intake
I have routed the Bypass Valve output back into the intake system using the
following: a piece of 90 degree 1 1/4" PVC, a piece of 1 1/4" ID
radiator hose, and the visible hose clamps.
I cut a small hole in the airbox to route the hose into. The radiator hose was ribbed, and the airbox hole diameter is the size of the hose as it tapers to its smallest diameter. Once inside the airbox, the hose expands to a larger diameter and holds itself in place, forming a seal to the plastic.
In order to make the hole, you do not have to remove the air cleaner box.
I first removed the filter, then covered the two openings in the box (to the
turbo and the fresh air intake) so no plastic pieces got into them. I
traced the outside diameter of the pipe on the inside of the air cleaner box.
I lined this up to the pipe coming off the BOV by just eyeballing it. The
pipe is a little flexible so you don't have to be exact. I first drilled a
hole in the center of the outline using the largest drill bit I had, then used a
Dremel to open the hole up the rest of the way and give it a smooth edge.
If you have a hole saw the same size as your pipe, you are all set.
This setup eliminates all noise from the Bypass Valve actuation. I don't think it makes any difference in the performance of the car, it is just nice and quiet now.
I need to trim the hose clamps yet (and probably paint them black), but here's the existing setup.