Originally Posted by GRAVEDIGGER
Yes, the hole where the flapper door arm went needs to be welded shut too. You do know that you will need to run an external wastegate mounted on the exhaust manifold now right?
Why? If the flapper is welded shut, sealed around the wastegate hole, then the flapper are hole should relevance. I mean it is nice to have it sealed and look professional. It would not leak, nor cause a bad o2 reading is the flapper door is sealed shut.
It is only going to cause a leak if you are using a recirculated housing. Also exhaust gases would have a hard time traveling back up the recirculation tube, it could be a potential leak.
If you used something like this flange it wouldnt matter, theres no reciruclation tube needed. But this also serves the same purpose as welding the flapper door shut, since it blocks off the flow of exhaust gases.
And yes a manifold wastegate is needed now. I would have left it and ran it off of the o2 housing, but it really is dictated by what manifold you are running.