Haha. This.
Please do this or you will be buying a new turbo!

 

Still with reference to your first pic: When you place the stock gasket over the studs and center the holes over the tapped holes for the bolts. Upon properly aligning it, you'll notice that the circle is incomplete since the gasket is not divided.

What I usually do here is that with the stock gasket properly aligned and centered I'll mark the partial circumference encompassed by the gasket with a fine point sharpie directly onto the machined flat metal mating surface where the gasket will reside. So you have a partial circle marked only. Then I'll fabricate a quick template and flip it over so that I can continue and close the circumference of the circle over the radius that falls onto the divider wall.(Maybe it can be achieved by flipping the gasket itself over. But, I don't know as I don't have one on hand? And it's been a while so I don't rememmber.)

There a slight amount of transposing. For example, you can trace the partial circle included on the gasket by tracing the partially complete circumference of the circle onto paper using the gasket as a partial template. Then if you don't have a circle template of that diameter available, you can just comlpete the outline of the circle by playing around with your little sister's adjustable school compass.

Once you have a quicky template fabbed up center and aligned it onto the partial circle that you already have marked with a sharpie and the gasket onto the machined mating surface of the housing. Thus you can completely close the circle with a sharpie. Now, scribe it.

Hope this preliminary info helps somewhat. There is probably some tricker way of doing this than my funky method. But, this is what you get for free. Ja Ja Ja

 

Once you have traced, transposed and then scribed the complete gasket circle, and further studied the telltale black marks of the exhaust gases you'll notice that the area to be ground between the scribed circle and the original edge of the exit chamber does not exhibit total concentricity. The gasket is a bit off center and it doesn't really line up well. There is part of the circle where the gasket closely hugs the edge of the exit chamber that requires little to no grinding, whereas there is another segment that can be ground out more significantly.

So, the proportionality of the grinding to be done is not going to be radially symmetrical with respect to the axis of the circle. There are segments where the gasket sits flush along the very edge of the chamber and thus needs no grinding at all. Whereas, there exist other sections where you can grind about 3/16" radially up to the scribed circle. Do you see what I mean?

Additionally, there is a limited segment of the imaginary circle where I tend to grind way beyond the marked line. That is specifically along the divider wall that separates the turbine exit chamber from the wastegate chamber. I like to sag the grinding down in this area because there is no gasket here anyway. So, I thin that wall down significantly working outward from the turbine exit side beyond the scribed circle.

So when all is said and done, you end up with about 270* that you can grind right up to the scribed circle and the remaining segment sagged down considerably beyond the limits of the scribed circle. As I stated at the outset...I am no expert. I am just attempting to demystify the process for the OP and other do-it your-selfers. LOL


If I can attain Heaven for a pice, why should you be envious?
.................................................. ................Opium smoker's proverb

 

I'm probably going to do this myself this winter! I've seen various posts over the seasons and basic results should be achievable for the average diyer!

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