EGR system

Vasja · Post by **Vasja** » Tue Jun 14, 2005 5:20 pm

I've heard that EGR valve is reducing power. Do I really need it? what will be, if I remove it?

xrian · Post by **xrian** » Tue Jun 14, 2005 5:24 pm

Who told you that line of crap?? The EGR valve is closed during acceleration and only open during part throttle operation.
Yes you need it IF you expect your car to pass any smog tests in your area.

xrattiracer · Post by **xrattiracer** » Tue Jun 14, 2005 7:23 pm

no it really doesnt affect power, and yes you can toss it. if for no other reason than the damn thing gets in your way when you try to work on the car. an efi car in good tune will pass most smog tests no problem without *any* emissions control devices.

Shigma · Post by **Shigma** » Wed Jun 15, 2005 9:45 am

Yeah I tossed it on my old XR and passed emissions no sweat.

Vasja · Post by **Vasja** » Wed Jun 22, 2005 3:53 pm

what will happen if I completely remove the EGR system? How will it effect on the engine work and gas mileage?

Post by **John Brennan** » Wed Jun 22, 2005 3:55 pm

First and foremost, you have to know the smog regs in your area. That's pretty much going to decide for you whether you can eliminate it or not. As I've read and understand, it improves gas mileage, but especially on a modded engine, probably becomes less important, and probably isn't much of a change either way.

vcallaway · Post by **vcallaway** » Wed Jun 22, 2005 8:47 pm

Not to mention it doesn't work on most of the cars anyways.

The concept is to reduce combustion temperature at cruising speed. When it works correctly the computer is supposed to run the engine lean and compensate by putting exhaust back into the intake stream. Since exhaust is inert it effectively reduces your combustion size.

When it works correctly it can reduce NOx emissions and improve fuel milage. Since our cars had a factory recall on the EGR it should tell you it is flakey.

It is not going to effect performance at all to have it in place. It is just an annoyance if you tinker with your car much.

MerkXRTurbo · Post by **MerkXRTurbo** » Thu Jun 23, 2005 8:58 am

Which brings up something that I think is really stupid. Who cares if you don't have EGR... who cares if you don't have a cat? It should be the end result that matters, but nope! You can burn as clean as a new Civic and still be "illegal".

Post by **DPDISXR4Ti** » Thu Jun 23, 2005 12:16 pm

Technically, it is against the law in ANY state to tamper with any emission control device, and the EGR would fall into that category. I start there, so that you know the law first.

Second, John is correct on it's operation. EGR functions primarily in steady cruise state and actually helps fuel mileage a bit by allowing more timing advance. It shrinks power during function, but since it shuts off as soon as more power is requested, you don't miss what you're not asking for. So all in all, it's not a bad thing and works quite well, substantially reducing NOX emissions as intended.

All that said, one of the first things I do when messing with a Lima motor is eliminate all the EGR stuff. I strive for engine bay simplicity, and all the EGR stuff flies in the face of that.

BTW, the difference between what your car *should* emit emission-wise, and the pass-fail limit is huge. Some states don't even test for NOX output, which is one of the key gases neutralized by the catalyst and reduced by EGR fucntion. Just because your car "passes" does not mean it is as clean as your neighbor's '99 Nissan Sentra with stock everything. If all the cars running around today passed the test, but were *near* the pass-fail limit, air quality would be horrible in many metro areas.

Just to be clear, yes, my statements above can be construed as being in conflict and hypocritical. But accurate nonetheless. Do as I say, not as I do!

Colin · Post by **Colin** » Thu Jun 23, 2005 12:18 pm

Or just move to a non-emissions state. Minnesota, baby.

Post by **wilky** » Thu Jun 23, 2005 12:25 pm

Colin wrote:Or just move to a non-emissions state. Minnesota, baby.

65% of airborn pollution where I live originates in the USA - most of it I suspect originates in Colin's Garage!!

I have eliminated the EGR from my XR with no noticeable difference. Still haven't removed the EGR pipe where it connects to the exhaust manifold though as it is seized - that will have to wait 'till the winter upgrade rebuild.

Wilky

merkurmaniac · Post by **merkurmaniac** » Thu Jun 30, 2005 4:34 pm

Speaking of which, some of the cars I followed in the convoy to Carlisle made me want to puke. Man, I can tell the schmell of a car that is not running a cat. It was definately worth it to be driving in front of them, not behind. Not mentioning any names...

Colin · Post by **Colin** » Fri Jul 01, 2005 1:44 am

I think what you were smelling was the oil seeping past the bad valve stem seals... but I'm sure my catless exhaust wasn't helping...

MerkXRTurbo · Post by **MerkXRTurbo** » Fri Jul 01, 2005 7:48 am

If a fuel injected car is truly running right I don't think there is much of a way to tell the difference (smell wise) between a car with or without a cat.

merkurmaniac · Post by **merkurmaniac** » Fri Jul 01, 2005 8:11 am

Well, all I can say is that each of the guys that I spoke to (knew them well enough to rib them) were not running cats. Perhaps in a bad state of tune as well, but I know none of them had cats.