I have just purchased the E46 turbo manifold for my 330Ci. It is a basic ebay manifold, Godspeed, Treadstone, Turbonetics etc. They all usually come from the same caster in China.
It is a cast unit which will be good for the person who has a daily driver. The exhaust flanges are split into two runners per flange. This allows room for expansion as the metal expands and contracts. Internally it is split into 2 banks front and back which meet up at the turbo end.
As it sits I believe the manifold does need some improvements in the ports. The manifold will get a Techline coatings Turbo X treatment, This will keep the heat in the manifold allowing me to pick up 150 rpm decrease in spool up. Another positive on the thermal barrier coating is that it will reduce under the hood temperatures.
Below are the pictures of the turbo manifold without any modification to it.
- Before installing the manifold in the car you will have to cut out some of the heat shielding near the firewall to make room for the wastegate flange and the 1.5″ wastegate extension pipe which will be just about 90º straight down from the flange.
I ported the ports on the manifold to match the gasket (exhaust) 3/1/2012.