It's the secondary air pump, not the egr system, it pumps air in to th exhaust on start up to effectively dilute the exhaust to make the emissions look better.

 

Does it offer any fuel consumption advantage or protect the cat? Can it be safely removed and plumbed out? It just seems like another thing to go wrong in my book

 

The secondary air injection does nothing to alter emissions itself, its purely there to get the catalyst get up to working temp quickly and hence be more effective.

Cats need to be really really hot before they do anything particularly useful

You can remove it no worries, the vacuum feed ensures that it only operates at idle/low throttle speeds when the cat is most likely to cool down.

 

Doesn't make any difference binning it really. It just burns any exces fuel/gasses before it reaches the CAT.

You can safly remove all the EGR air pump. Theres somone selling a Janspeed 4-2-1 manifold on here as well, so thats a good excusse to buy it and bin that lot anyway.

Made my little 1.4 16v look bigger than my 2.0. I've actually got more room now with the redtop lmao .

 

Well thanks for the replies - I'm glad I know what it actually does now!

 

actually, SAI does decrease emissions - both directly and by giving the cat better conditions to work in.

EGR is designed to lower combustion temps, again reducing emissions - but bear in mind that the ECU will have an ignition map based on these lower temps - by removing EGR you will increase temps and risk pinking (assuming you remove it in a way which stop the ECU picking up a fault and going into limp home)

 

What does SAI mean?

Yes, I won't be removing either of them (not my car for a start ) I was mainly interested in the functions of these parts of the engine.

 

Vauxhall Info here:

http://82.34.51.160/sytemsandsoftwa...redevelopment/systems/automotive/How_to/General/EGRandSecondaryAirInjection.htm