Recently saw the chance to grab a different exhaust manifold from the china copy that I already had. Bought it as an unknown japanese brand as unlike all the china copies, it hasn't been mirror polished (not that that really means anything). I've felt the the joining of the first runner to the collector in the china copy I have is a little on the severe side, coming in at almost 90deg. When I saw this japanese one, it immediately looked better, and also different too as the runners are lined up to the collector as opposed to being in a quadrant (square) type collector.
Anyway, here are a few pics of the differences between the two. I have noticed that a few of the china copies come out now are getting better - but the price of this 2nd hand was only $230 so I can't complain. I'll take to C-Red and see what they say about its likely strength as it has minimal bracing. Note that the china copy looks cleaner at this point because it's been ceramically coated. This will be done also to the Jap one, and may also consider cryogenically treating it to give it some extra strength.
Pics of the SR20DET manifolds:
- Side View Jap | China Copy
- Top View Jap | China Copy
- Inside Collector Jap | China Copy
- Mounting Plate Jap | China Copy
- Inside Runner Jap | China Copy
- Thickness Difference
If anyone has any comment, or recognises the manifold and it who it was possibly made by, please let me know.