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Custom O2 Housing

90K views 528 replies 56 participants last post by  solerpwr 
#1 · (Edited)
I have a friend making me a custom O2 housing for my '89 GT and it's actually coming along nicely.

The custom O2 housing looks very similar to the ones made in the past with a divorced wastegate pipe. This will bolt up in the OEM location and enable me to keep my A/C if I still had it and will be 2.5" vs the stock 1 7/8".

Here are the bends being used:


Here is the jig made off the OEM O2 housing:





Here is the start of the new custom O2 housing:


All it should need now is some clean up and an O2 bung. The wastegate tube isn't as graduated as I anticipated, but I think it looks really good.







What do you guys think?
 
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#5 ·
Looks good.

Don't forget to add a divider to sit inside the exhaust housing and separate the gasses into the 2 pipes.
 
#7 ·
He'll need a turbine housing and gasket on hand to get it right.

It doesn't need to be airtight just snug inside the turbine housing.
 
#8 ·
What sucks is I used to have a turbine, but scrapped it... If I get measurements, do you think he could fabricate the divider that way? How important is the indention/flat edge around the wastegate port on the flange? Like this one pictured. I assume it's for the the wastegate to fully open. With the larger hole of my setup, do you think it'd be fine without the indention?
 
#9 ·
If you get him measurements he should be OK.
He can make it a little bigger than the measurements indicate and then you can adjust the divider to suit upon assembly.
BTW, It really only needs a couple of decent tack welds to attach it to the flange, allowing you plenty of room to adjust it to fit.

The milled area next to the Waste-Gate port is to allow the wastegate flapper to open fully.
Depending on the size of the WG port on the flange you have there it might not be neccessary.
You'll have to check the WG range of movement upon assembly and possibly grind with a burr if required.
 
#10 ·
OH MY GOD.

Please make more, and put them up for sale.

If the price is below $200, or even well below...I'm hella down.
 
#13 ·
I seriously can't stop looking at these pics. I have an mx6 that needs one, and a 626gt that could use one lol.

I've shown this to my PGT friend and he is down too.

This is some serious stuff if it actually gets off the ground. (not holding my breath though...)
 
#15 ·
I was able to pull a turbine housing and sent it off to my friend. The wastegate actuator moves the flapper roughly 1/2" and once fully open, does break the surface where the flange would meet the turbine housing. So he'll know for sure now if the area next to the waste gate port needs milled or not and will be able to get the divider just right.

Once he makes mine, sends it to me & I get it installed to see if there are any bugs to work out, he intends to make more if there is a demand for them. He thinks he'll be able to sell them for ~$150.

Gavin, I sent my friend several links with examples of what I wanted and he basically combined your waste gate pipe design to Jake's final design and that is what he came up with. It looks great! Thanks for the link to that other thread. I had not come across that one yet. Lots of great info!

I'll keep you guys posted!
 
#16 · (Edited)
Here are more pictures of it mated to the turbine housing I pulled.




As you can see all the 17mm OEM nuts go on, but the one furthest to the right side below where the O2 bung will go will not accept a socket. A stubby wrench will have to do or smaller nut for a socket.

As far as the waste gate goes, it seems that it is able to open far enough (at least .5"). So hopefully no need to mill out a section for the flapper gate.

Still need to get the divider fence made and O2 bung placed.
 
#18 ·
Getting closer and closer.

Honestly you could call it a day after the O2 bung and wastegate divider, but if you really want to go a bit further...

As you can see all the 17mm OEM nuts go on, but the one furthest to the right side below where the O2 bung will go will not accept a socket.

Thats a picture of monoxidechilds original O2 housing from jake. You can see the small cutout for additional clearance at the bolt to the right of the bung. Its a bit more work to do, but if your guy is up for it.....or, you could...

A stubby wrench will have to do or smaller nut for a socket.


I ran into the same issue and found a 15mm hex, m10x1.5 nut for that spot. It was actually originally a flanged nut, but I zipped off the flanges so that it would clear.

Gavin
 
#17 ·
Today just happens to be my bday, if I get enough $, ill order one right NOW.

IT LOOKS AWESOME.
 
#21 ·
Make it. I'll buy two.

It would be just the excuse I need to do a proper full exhaust on my mint OEM '90 626GT Touring with 75k original miles.

If I'm feeling spry I might buy three, to sell one to some poor sclub who missed out on the initlal build.

Another thought that would add cost, but something I'd personally pay for, milling the flanges flat after welding to ensure flatness for better sealing, resistance to bolt breakage...Yes, It's happened to me, too many times....
 
#23 ·
Another thought that would add cost, but something I'd personally pay for, milling the flanges flat after welding to ensure flatness for better sealing, resistance to bolt breakage...Yes, It's happened to me, too many times....
I have found bolting the flange up to a spare piece (turbo hot housing....) or a flat piece of metal with bolt holes drilled in the right spots eliminates most of the heat distortion.
 
#27 · (Edited)
Well, good news.

I think we have plenty of clearance for the wastegate. Here are some pictures of clearance and amount of movement the flapper gets. What do you guys think? I don't think it would be necessary to mill out that section of the flange.


Here is a side shot with the gate positioned roughly 1/2" from closed position where the actuator would fully open the flapper.


Here is how far the gate can actually open.



He polished and cleaned it up. This is how they will be delivered.

For the fence he will probably just shear a piece to size and roll it to a perfect fit. Once the fence is in and he gets the 02 bung on, it will be ready to send to me to be tested out.



 
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