Hi I just bought my first rotary (s5 vert) and I’m about to put my motor back in. I was curious if deleting the air pump/emissions control is worth it and what the recommendations are. I’m currently on a stock ecu and would like to keep full functionality of 5th and 6th ports

 

Easiest way on a S5 to keep the full functionality of the 5th and 6th ports (and the VDI as well) is to keep the air pump and air control valve and ensure it is all functioning properly. On the S5 these systems operate from air pressure from the air pump. Also the air pump supplies air to the main catalytic converter. IIRC without that air the life span is shortened. If you remove it in lieu of some sort of header/pre-silencer or downpipe/ pre-silencer combo you still need the air pump for the 5th and 6th ports. The air that would've went to the cat will just harmlessly dump to the atmosphere.

 

Thank you! that answers my concern as I plan to get an aftermarket exhaust. Would I be able to place a rubber cap where the pipe/tube comes out of the air pump or would that create unwanted backpressure. Also I assume I would be fine removing the charcoal canister as well. sorry for all the questions I'm just trying to clean up the engine bay as much as possible before I put the motor back in and these forums have been an amazing resource.

 

That is exactly what I did when I first installed my header. I ran it that way for a few months before I eventually removed my air pump and ACV. This was a long time ago but I don't recall any issues. I'm just not sure if it's necessary.
Even though my air pump and ACV is gone I never did touch the charcoal canister. I'm not sure there is anything to gain by doing so.