Modded stock o2 housing

[strippedlug]

Hey this may seem like a dumb question, but I want to be sure none the less.
I took a spare OE O2 housing to a buddy of mine at Metal Magic, and he's making me a Tial 38mm wastegate flange so my wastegate will mount directly to the O2 housing.

My question is this. I didn't ask him to re-route the wastegate piping. Is it okay to install a block-off plate between the exhaust downpipe and the O2 housing, so a seal is still created? Or should I hack the wastegate side of the O2 pipe and weld it closed?

I'm kicking myself for not having researched this more before I gave the guy his instructions, but it's not too late to redirect him.

What's the best way to go about this? Thanks

[drcustom]

Sorry if I'm misunderstanding, but here goes...

I'm assuming you're using a mitsu style turbo, that has the stock housing, with the wastegate flapper wide open or missing.

I feel like I might be missing something, but...I'm assuming your buddy is just going to tap into the wastegate vein of the housing, in which case there's no need to block off the hole on the upstream side...the wastegate will need the feed open anyways because that's where it will get the exhaust to vent...but without the lower side of it blocked off there's no way to be sure the wastegate is venting enough exhaust gas...

It needs to be like this...turbo -> wastegate -> barrier when wastegate is closed (meaning the wastegate is 100% in the path of the wastegate exhaust). If he just taps into the 02, then there's no gurantee that the exhaust gas will even go through the wastegate, because it has the option to just keep going out the exhaust...but then again it might not (I'm guessing that's why you're asking this question!) it's tough to get in there and weld though, I'm interested to see what people have to say...I would expect you'd have a hard time controlling high boost or that it might not settle exactly where you want it, but it might be worth a try.

I feel like I'm telling you something you already know, but, if you just install a block off between the 02 and downpipe, you'll have a problem because that path needs to be open before the wastegate opens...and even after not all of the exhaust goes through the gate.

[milehightalon]

Is it okay to install a block-off plate between the exhaust downpipe and the O2 housing, so a seal is still created?

This would result in no exhaust being able to exit except when the wastegate was open, which would never happen because the car wouldn't run.

I'd scrap the whole project. Way to much hassle for results that will be lackluster at best.

[strippedlug]

Milehigh- no not to block off the entire exhaust. That would be useless. I meant sealing off the wastegate vein of the O2 housing so the only escape of exhaust gases on the wastegate side of the housing would be through the new flange being made.
DRCU you're understanding exactly right. Sorry I wasn't more clear, but yes that is what I was trying to acheive. I see where you're coming from: " I would expect you'd have a hard time controlling high boost or might not settle..." Is this because there would be a "pocket" of wastegate exaust trapped between the newly welded seal-off and the WG? In my mind what you're saying makes perfect sense, I just want to make sure I am on the same page here.
Because I was getting more and more uneasy about this rig, I sent Metal Magic a picture of Straightline Specialties's 38mm Tial O2 housing, and basically asked him to build something similar, in addition to trying to mod the stock piece. That way I can try both, and if the stock housing works well (who knows) I'll definately post it with pics. I don't have high hopes, but it's worth a try! Thanks alot for the replies !
Shane