The EGR (exhaust gas recirculation) system only brings exhaust into the intake when the throttle is closed at higher rpms. Think about pulling the plunger on a syringe with the cap blocked off.

The air pump blows into the catalytic converter to provide enough oxygen to finish burning the unburned fuel so it doesn't clog the cat.

Neither one is an albatross around your motor's neck.

 

EGR is normally open at part throttle, not deceleration. It actually helps to prevent pinging, among other things. If you remove it, you should tune the engine to run properly without it.

 

Not trying to stir a pot here or anything, but emission devices are federally mandated and removing any of them is against federal laws and regulations.

Some states and local jurisdictions test and check emission equipment, some don't. Just because your local jurisdiction doesn't test or check for them, doesn't mean it is legal to remove them and still operate the vehicle on public roads.

 

Correct. That is why we do not discuss removing emission control components.

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