Wednesday, May 7, 2014

Turbo Exhaust Manifold

Exhaust parts are here

We now have all the parts needed to start working on the Turbo Exhaust Manifold.

Here they are; the shiny stainless steel tube bends, the collector "flutes", the plasma cut flange that fits to the engine exhaust side, the turbo flanges and their gaskets: 

Step 1 - position the turbochargers

We have two turbos, each capable of ca 400 hp.  To install  them we need to consider that 2 x 400 hp equates quite a bit of air and even more of exhaust fumes per second.  And all of this air and exhaust will need to go through the turbos, either on the cold side or the hot side.  This translates to pipes, pipes, pipes and plumbing, plumbing plumbing. 

In the picture we see the two chargers hanging in the precision jig at their very exactly calculated position. The red and yellow caps are on air side. The yellow is input air and the red is compressed air out. The hot side is behind, and will have hot, high energy, exhaust coming in from the engine and it will output less hot and less energized exhaust to the rest of the exhaust system. The energy in between will propel the compressor at the air side. 

Time to figure out how the pipes should bend. Lacking sophisticated CAD software we fabricated a sophisticated wooden jig. With additional intricate lines on a paper we concluded where to cut the bends to meet up with both flanges and the collector flute in between. 

Next is welding it together. With in house extensive experience of MIG welding - in all sort of materials ranging from pure rust to under body bitumen, and the occasional mild steel -  I say,  this must be easy. Add to this that stainless steel tubes deserve welding not with MIG but with TIG.   And TIG is the pinnacle of all welding techniques.  Its supposed to give you so much control and feeling that failure is not possible.

But, lets first make some test:

Something was terribly wrong. None of the professional look I was there, especially on the inside...

After some Youtubing and Googling I realize that TIG welding stainless requires "purge gas" or "root gas" on the inside. This is because stainless contains chrome and chrome will combine with carbon dioxide in the air and form an ugly crust. 

But with an extra hose from the TIG gas tank and a plug on the pipe end the welds started to improve:

Now the inside looks a lot better:

Next is to measure more and cut up all the pipe bends and actually start welding the real thing.  More will come. 

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