OK so the C18XE comes with a cast manifold leading into twin downpipes, it seems to share this manifold with the c18xel and c18sel.
Seems from what I read that the reason for the cast manifold is to generate more heat the warm up the cat as the 4 branch fitted to earlier engines didnt need to do that.
Also there is a take off on the cast manifold by the dis unit for the egr system although on the c18xe its not used and the dis unit mounting plate is not drilled for egr.
I am wondering if it would be worth the time and trouble to manufacture/modify a 4 branch exhaust for this engine?
I know some are available but they cost £350 I think.
Has anyone had their standard c18xe in the rollers and probably just as important has anyone fitted a four branch to one of these engines, removed the cat and rollered it then.
What would you think the gains in bhp would be from this?
I have had a look at a mk2 gte manifold I have here and think that with my mill and some stainless plate I can cut a good mounting flange for the pipes and cut off the original gte one, then weld it to the one made to suit the c18xe.
Pipe size may be a little large for a 1.8 but it should do the job ok.
Thoughts and comments please?