Why the hell is this thing important and do cars really need it...

Why the hell is this thing important and do cars really need it? I know what it does but god damn is it in a inconvenient place in my engine bay

bcuz monies

You need it to pass smog. If no smog in your zone, then you can plug off the hole.

EGR only activated off-idle and not at WOT. It dilutes the combustion chamber with "inert" exhaust gasses and acts as a space-filler so the cylinder cant fill up with any more air/fuel mixture. It'll help with your cruising MPG's and what not.

Also since it introduces exhaust gasses to your intake manifold, prepare for a black soot-covered mess if you ever take your intake manifold off or apart.

Anyone who's ever worked on a late 90's or early 2000's Honda is cursing them. I'm looking at you BB6's!

>"I know what it does"
>Don't care lol, let me explain what it does anyway so everyone can see that I know my shit

I foiund it interesting though.

Question: Does a mildly soot coated intake manifold noticeably impede performance or efficiency.
Because when I had the intake hose off on my car for a timing belt job I cleaned the throttle body and noticed the manifold coated in black soot (not very thick, but everywhere on the walls), too.
I decided to just leave it because I was too lazy to take the whole manifold off. Was I wrong?

Because thinks of the children!

It's obviously not ideal if you are looking for perfect air flow to extract every last drop of power out of an already modified engine, but if someone were to clean your whole manifold overnight without telling you, you wouldn't notice the difference

I heard people disconnect their egr and it runs like shit.

So this device would be unnecessary if your engine has variable valve timing right? Since vvt does the same job by precisely controlling the volume of gas entering and leaving the cylinder?

Think of egr as the way a lot of newer cars hyperventilate

Thanks.

>disconnect their egr and it runs like shit
Older models used vacuum and exhaust pressure to operate. Morons like your friends would disconnect the vacuum hose, but the exhaust pressure still was active, fucking up the balance.

If it is working ok leave it in place, it is just saving you gas. It may reduce engine wear by reducing combustion temp at steady acceleration too. Just FYI, I just replaced the head gaskets on my car and there was no soot buildup anywhere(intake included). Car has 150k miles. If you ever remove it you will probably lose gas mileage (1-3mpg from what I hear), but suffer no other effects as long as you seal everything up right.

>mfw I have no face or EGR

>lose gas mileage
that's not true for leadfoots

While you're pretty well bang on, the one mistaken presumption here is that an EGR helps with your cruising MPG. It does not, and if anything a functioning EGR hampers MPG by way of lowering power density (ie; more throttle is required to maintain a particular RPM at a given load), there's no free lunch, and simply limiting your air/fuel mixture does not necessarily save fuel usage to achieve a given task.
EGR is there to serve one purpose and that's to lower combustion chamber temperature.

>EGR is there to serve one purpose and that's to lower combustion chamber temperature
by introducing hot exhaust gas, youre rong

>by introducing hot exhaust gas, youre rong
That's a complete oversight. It displaces air/fuel mixture with a non combustible gas, making a smaller "bang" and therefore lowering combustion temperatures.
And that's before taking into account most EGRs are routed through a cooling block.
I think you need to look into the function of EGRs a little more.

few hundred degree exhaust gas, 2000 degree combustion temp...

also alows leaner mixes to improve mpg without making nox, as the egr keeps temps below 2500.

tl,dr;
Regardless of the gas temperature introduced, the output temperature is still lower.

And you are an idiot

>improve mpg
>egr
pick one

That actually makes a lot of sense. Dunno why these cunts don't get it.

They'd work great if every car with one was run properly warm every single drive

Now, put them in cars here in Norway... most cars are diesels, and most folk arent able to run it warm on their way to work or the store. This results in the EGR being at fault for something like 60% of diesel car failures here