EGR system

XR4Ti / Sierra / Sierra Cosworth Discussions - Questions, problem resolution, general talk, technical tips and modifications.
Merkur Club web site
Vasja
Level 1
Level 1
Posts: 64
Joined: Sat Nov 20, 2004 5:58 am
Location: Europe, Estonia
Contact:

EGR system

Post by Vasja »

I've heard that EGR valve is reducing power. Do I really need it? what will be, if I remove it?
85 XR4Ti in Estonia. one of the three ones :)
xrian
Level 7
Level 7
Posts: 1584
Joined: Wed Oct 20, 2004 6:35 pm
Location: Southern Ontario

Post by xrian »

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.
Ian G-J
Ontario, Canada
xrattiracer
Level 7
Level 7
Posts: 1108
Joined: Wed Feb 16, 2005 1:08 pm
Location: Seattle, WA

Post by xrattiracer »

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.
86 Silver XR4Ti. 'squirted. 12.7@111
03 VW Golf tdi
05 Yamaha FZ6
Shigma
Level 3
Level 3
Posts: 271
Joined: Wed Apr 28, 2004 12:13 pm
Location: West Hartford, CT

Post by Shigma »

Yeah I tossed it on my old XR and passed emissions no sweat.
01 Cavalier - it still runs!
08 Evo X GSR - Stock.. for now
Vasja
Level 1
Level 1
Posts: 64
Joined: Sat Nov 20, 2004 5:58 am
Location: Europe, Estonia
Contact:

Post by Vasja »

what will happen if I completely remove the EGR system? How will it effect on the engine work and gas mileage?
85 XR4Ti in Estonia. one of the three ones :)
User avatar
John Brennan
Level 8
Posts: 11630
Joined: Wed Jun 18, 2003 4:19 pm
Location: Scottsdale, AZ "Summer Is Coming"

Post by John Brennan »

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.
This is my car, and these are my people!
1989 XR4Ti 5-Speed
2001 BMW Z3 3.0i 5-Speed
2015 Fiesta ST
2020 Edge 2.0 Ecoboost
vcallaway
Level 5
Level 5
Posts: 577
Joined: Wed Apr 16, 2003 3:26 pm
Location: Lakebay, WA, USA
Contact:

Post by vcallaway »

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.
Vince Callaway
MerkXRTurbo
Level 7
Level 7
Posts: 4612
Joined: Mon May 17, 2004 11:08 pm
Location: Vancouver, WA
Contact:

Post by MerkXRTurbo »

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". :roll:
3" mandrel bent exhaust, Ported/Polished head, 1.89/1.57 valves, Gutted uppper/Knife edge lower intake, T3/T4, LA3, Big VAM, Cold air intake, 40bob header, Gillis valve, Forge BOV, Mustang SVO T5, Conquest intercooler, 20psi.
User avatar
DPDISXR4Ti
Site Admin
Posts: 14042
Joined: Wed Jan 08, 2003 11:40 pm
Location: New York

Post by DPDISXR4Ti »

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. :roll:

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! :twisted:
Last edited by DPDISXR4Ti on Thu Jun 23, 2005 12:18 pm, edited 1 time in total.
Colin
Level 7
Level 7
Posts: 3396
Joined: Tue May 27, 2003 1:35 am
Location: Minnesota
Contact:

Post by Colin »

Or just move to a non-emissions state. Minnesota, baby. :lol:
Instagram @colinrdoyle
89 Scorpio 2300-16V // 07 F-650 Cummins // 00 Beetle TDI
File to fit, paint to match.
wilky
Level 6
Level 6
Posts: 807
Joined: Sat May 24, 2003 9:17 pm
Location: Sarnia, Ontario, Canada

Post by wilky »

Colin wrote:Or just move to a non-emissions state. Minnesota, baby. :lol:
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
Seeking relationship with sexy lady Merkur owner (send pic of Merkur).
merkurmaniac
Level 5
Level 5
Posts: 742
Joined: Sat Jan 11, 2003 1:34 pm
Location: Sugar Land TX
Contact:

Post by merkurmaniac »

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
Level 7
Level 7
Posts: 3396
Joined: Tue May 27, 2003 1:35 am
Location: Minnesota
Contact:

Post by Colin »

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... :oops:
Instagram @colinrdoyle
89 Scorpio 2300-16V // 07 F-650 Cummins // 00 Beetle TDI
File to fit, paint to match.
MerkXRTurbo
Level 7
Level 7
Posts: 4612
Joined: Mon May 17, 2004 11:08 pm
Location: Vancouver, WA
Contact:

Post by MerkXRTurbo »

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.
3" mandrel bent exhaust, Ported/Polished head, 1.89/1.57 valves, Gutted uppper/Knife edge lower intake, T3/T4, LA3, Big VAM, Cold air intake, 40bob header, Gillis valve, Forge BOV, Mustang SVO T5, Conquest intercooler, 20psi.
merkurmaniac
Level 5
Level 5
Posts: 742
Joined: Sat Jan 11, 2003 1:34 pm
Location: Sugar Land TX
Contact:

Post by merkurmaniac »

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.
Post Reply