I welded a custom automotive intake manifold this weekend for a Toyota Celica, which was going to be getting a turbo on it as well. Here is the final product:
I started with these "raw materials". Some nice CNC milled pieces. Everything was 6061 aluminum.
The intake runner tubes (1/8" thick, 2" OD tubing) had to be:
1. cut to a specific angle, (which I did on my horizontal bandsaw)
2. formed into this cylinder head flange shape, (which I did with a vice and a hammer)
3. beveled, deburred and cleaned for welding, (beveling helps encourage good, consistent penetration, with no hot cracking on 6061 butt joints)
4. fitted up nicely on both ends to the head flange and the plenum base.
I then proceeded to tack weld the runners up to the head flange and the plenum base,
...and I fully welded the runners to the plenum.
(On the other side of this joint, I used my die grinder to deburr the transition from the base of the plenum opening to the runner tubing piece.)
I bolted the head flange to a fixture to prevent warping during welding (and it worked).
(...continued on next post)