EGR question

[Squirrel]

Just what exactly does the EGR do (please don't say recirculate exhaust gases). But how does it function and its purpose. I have asked quite few people that are very knowledgable about car and all I got was "It recirculates exhaust gases." I just want a somewhat more detailed explanation. I couldn't really find anything that addresses this specifically. Also can it simply be eliminated?

[240slider]

The egr valve uses exhaust gases to lower combustion chamber tempertaures to prevent detonation. it uses engine vacuum to operate .inside the egr it contains a plunger like diaphragm which opens and closes .the egr is mostly used during idle and low throttle demand .it functions at higher speed but is needed less because of the W.O.T .I personally would not try to eliminate it .because anything that can keep me from blowing up my engine is needed .

[elwesso]

ITs main thing is for emissions...

By lowering the combustion chamber temps this reduces NOx emissions.....

It also does help against detonation, but I wouldnt say that running without EGR would cause the car to detonate... I am running no EGR (bad solenoid) and i didnt experience any problems. I fix at my convience.....

BTW, the EGR comes on ONLY during cruise (1500-2500ish RPM).. DOESNT come on during idle, or WOT..

It is controlled by a small solenoid that activiate the vacuum, to lift the plunger.....

I wouldnt however attempt to eliminate it either... IT doesnt reduce performance, and its another thing that you couldmess something up on.....

[Squirrel]

Thanks for the help, but how exactly does recirculating exhaust gases reduce combustion chamber temps(if I recall correctly that stuff is usually pretty hot). Also the reason I was asking is because I was contemplating fabricating an Intake manifold and taking that thing off would sure simplify things.....

[elwesso]

Well.. It doesnt cool how you would think... When the gas (therefore inert) enters the combustion chamber, it causes the explosion of the charge to be less intense (less intensity means less heat)...

This however does at a small enough scale that it wouldnt affect gas mileage enough.....

Look at it this way

If a normal charge will produce 50BTU (just making these up), then maybe with the EGR the same charge would put out 45BTU.. It MIGHT produce a 100th of a MPG difference..

If you look at the size of the port, its smaller than the diamater of your pinky (from valve to plenum)..

I think that you would be shooting in the dark doing this.. I would also not recommend changing the plenum for a custom one.. They are carefully engineered, and changing them to remove EGR or other vacuum lines wouldnt do anything......