In this post (long ago), I prepared my car for some major upgrades. I promissed to start a new thread on my manifold upgrade.
My car originally came with the stainless exhaust manifold that is known to tear apart, especially when the engine is tuned. So when I decided to change the turbo, it was obvious to me that I would also change the manifold it is attached to. The cast manifolds of the older E46's and E39's are becoming difficult to get in Europe, since almost everybody knows everyone with the newer M57 engine wants to have one... except for the seller I found. He sold it as a manifold for a petrol engine, but in the picture I recognised it as the one I needed. So 50 euros made me the proud owner of the correct manifold.
When looking into the ports however, top and bottom are narrowed to make space for tools that are needed to torque down the mounting nuts. My tools are not as big as the factory ones I guess, So I welded up the recesses on the outside:
Of course, welding cast iron is not easy... before every weld, I heated up the complete part with a huge gas torch. And also after doing the welds, I let it cool down in a 'bed' of isolating glasswool, which took a complete day to let it cool down fully! Despite this, I couldn't help some cracks appearing, so I welded those again using the same method:
After all the welding was done, I took it to work where we have a huge oven. The part went in for a complete day at high temp (forget how high; several hundreds degrees of Celcius) to cure out all stress that would still be in it.
It came out nicely without extra cracks, but a little warped, which again at work, I smoothed out on a milling machine:
I had to take of 2,5 mm to make it fully flat again!
I didn't want to put the turbo closer to the engine, since there is only a tiny gap in standard guise:
(on the right the turbo; on the left the block)
So I made filling plates to compensate for the loss of distance between turbo and block. This also lead to the need of 2 gaskets per exhaust port; one on every side of the filler plate. To keep everything securely in place, the filler plates and gaskets were located on the manifold by small guidance pins (sorry, forgot to take pictures)...
But all this was needed to do this:
Due to the extra plates and gaskets, it was a real pain to assemble, but it did fit!
Now, you'll be asking "what's the gain of all this effort?" More to that in a next post...
My car originally came with the stainless exhaust manifold that is known to tear apart, especially when the engine is tuned. So when I decided to change the turbo, it was obvious to me that I would also change the manifold it is attached to. The cast manifolds of the older E46's and E39's are becoming difficult to get in Europe, since almost everybody knows everyone with the newer M57 engine wants to have one... except for the seller I found. He sold it as a manifold for a petrol engine, but in the picture I recognised it as the one I needed. So 50 euros made me the proud owner of the correct manifold.
When looking into the ports however, top and bottom are narrowed to make space for tools that are needed to torque down the mounting nuts. My tools are not as big as the factory ones I guess, So I welded up the recesses on the outside:
Of course, welding cast iron is not easy... before every weld, I heated up the complete part with a huge gas torch. And also after doing the welds, I let it cool down in a 'bed' of isolating glasswool, which took a complete day to let it cool down fully! Despite this, I couldn't help some cracks appearing, so I welded those again using the same method:
After all the welding was done, I took it to work where we have a huge oven. The part went in for a complete day at high temp (forget how high; several hundreds degrees of Celcius) to cure out all stress that would still be in it.
It came out nicely without extra cracks, but a little warped, which again at work, I smoothed out on a milling machine:
I had to take of 2,5 mm to make it fully flat again!
I didn't want to put the turbo closer to the engine, since there is only a tiny gap in standard guise:
(on the right the turbo; on the left the block)
So I made filling plates to compensate for the loss of distance between turbo and block. This also lead to the need of 2 gaskets per exhaust port; one on every side of the filler plate. To keep everything securely in place, the filler plates and gaskets were located on the manifold by small guidance pins (sorry, forgot to take pictures)...
But all this was needed to do this:
Due to the extra plates and gaskets, it was a real pain to assemble, but it did fit!
Now, you'll be asking "what's the gain of all this effort?" More to that in a next post...
