Questions about catalytic converter removal
 

Hi all,
I would remove the cat from the stock exhaust of my '93 FD3S.
I just have some questions. I know that I should to remove the air pump but is this necessary?
My ECU is stock but I tried anyway to remove the relay and the also the electrical connector on the top of the air pump and the car is exactly as before, the idle is perfect and also while driving (except for the annoying sound of the air pump).
Now if I remove the cat could I have problems in future?
Thanks!

If you have removed the cat, then the air pump serves no purpose. It can be removed (you will need to add an idler pulley and switch belts) as well as the ACV and associated emissions components.

But, in doing so you will raise the boost. Best port the wastegates first to avoid blowing the engine due to excessive boost and lack of fuel.