Following up on the intake manifold carbon cleaning project I did on a 2001 VW Golf TDI; http://www.everlastgenerators.com/fo...ru-s-project-2)

I set out to remove the offending EGR system, to ensure that the clogged intake problem will never recur.

Engine compartment before and after EGR system removal:
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I modified the intake pipe with the EGR valve by first removing the valve components, and roughly grinding away the supporting structure, chamfering the edges of the holes that needed to be welded shut, which I would do via the AC TIG process:
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I then patched the holes using TIG and 4043 aluminum filler rod. This was tricky because it turns out the parent metals were not a very pure aluminum alloy, it was substantiall a zinc-based pot metal. This material is challenging to TIG weld because if you get the zinc too hot, it boils, causing lots of smut and porosity. I could have welded with pot metal filler rod to match the metallurgy of the parent alloy better, but it wasn't until after I began welding that I realized I was dealing with pot metal. 4043 works OK over pot metal, I did get a little porosity but small enough to not cause any problems. After the welding, I ground out the inside and outside carefully using die-grinder powered porting tools, to make the surfaces nice and smooth and eliminate visual evidence of there ever being an EGR valve designed on this part in the first place:
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Here is a view comparing the inside of this pipe, before and after EGR valve removal:
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And I finished the exterior by bead blasting it (put tape on the holes to cover the interior and keep the glass beads out of there) for an OEM look. The goal is to have it look as if the piece was designed by the factory without the EGR valve.
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Here is a detailed shot of the completed intake pipe with EGR valve removed, after installation:
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To make the system work without the EGR valve, I also removed the EGR cooler, fabricated a block-off plate (mild steel) to go on the exhaust manifold, and rerouted the coolant lines a bit. Replaced the vacuum line going to the EGR valve with a vacuum cap. And had the ECU reprogrammed to work well without the EGR valve (otherwise it would have been throwing fault codes.)

One benefit of this custom made piece not readily available in any alternatives, is that it retains the air shutoff valve (the throttle valve looking thing), which is an important safety feature of the engine. The shutoff valve furthermore helps the engine shut off more smoothly (with less noticeable shaking during engine shutdown), which seems like a nice refinement that is desirable to keep.