03 VW Golf tdi
05 Yamaha FZ6
- John Brennan
- Level 8
- Posts: 11630
- Joined: Wed Jun 18, 2003 4:19 pm
- Location: Scottsdale, AZ "Summer Is Coming"
1989 XR4Ti 5-Speed
2001 BMW Z3 3.0i 5-Speed
2015 Fiesta ST
2020 Edge 2.0 Ecoboost
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.
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!
65% of airborn pollution where I live originates in the USA - most of it I suspect originates in Colin's Garage!!Colin wrote:Or just move to a non-emissions state. Minnesota, baby.
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.