I've seen turbos like that before.. Its actually a slip in downpipe.. Usually the turbo and downpipe are both mounted to a stationary objecto- like the motor. Old style Formula 1 used it dues to the tremendous EGTs and flex in the chassis- to prevent breaking the housing..
I definately wouldnt reccomend welding to it- if you get it too hot you could end up warping the housing and throwing away a new turbo..

 

I would absolutly NOT weld anything to that housing unless you want your impeller bore and countour to distort and make your impeller blades hit the side walls!
Get something made up of the same or similar cast iron to a size on size condition, heat up the new peice in an oven to about 350 degrees and put your turbo in the freezer for a couple hours.
They will sweat together and be nearly impossible to take apart and will not leak exhaust either.
When the turbo warms up under normal operating conditions both parts will expand at the same rates and stay tight.
Sound good??

 

Thermal fit. They work well if the clearances are right. I did one once in my machining class in college. Everybody was using a press and distorting their part in the process. I put one part in the freezer, one it the oven and they slipped together by hand.

 

Thanks guys, when I opened it up I was like WTF!!!
It wasnt the seller, those are pictures from another auction, not the turbo I have, so that is the way it is susposed to be. I thought I read something on Garrett's website about some tangental mounting or something....
There is no way I am going to weld on a brand new turbo, period.

Yes, it is going on a home build jet engine, all I really need is a way to attach an exhaust nozzle to it, so a simple hose clamp or muffler clamp will work just peachy.
Heres the link to the engine I am "borrowing" ideas from

http://www.rcdon.com/html/experimental_projects.html

 

any other ideas how mount to this sucker?