Hello all,
Has anyone removed the secondary cats on the 2.0 or 2.8 car? If so, what difference can you expect. I had a jcw mini r56 before buying the e89, just wanted an idea of difference in z4 if anyone can help.
D
Not sure what you mean by secondary CAT - as the N20 only has one CAT as I am aware?
I have replaced my primary cat with one that has the internals removed so it looks OEM;
[*]It sounds very boomy almost scooby sound at startup - but over 1000 rpm is disappears.
[*]Can not comment on emissions as yet
[*]Yes there is some improvement in performance and torque I would estimate around 20 BHP based on rolling roads prior and previous.
[*]You could have CEL lights - if you don't have a solution to remove them.
Maybe I am wrong, if you remove the primary cat and just do a straight through job it will have the same effect as above. I am just looking for something a little fruitier and don't fancy the back box delete option (too loud) I think
