Blocking off EGR

[Fuelrod]

Just my thoughts...EGR systems reduce combustion temperatures at "normal" throttle settings. This is done to reduce NOx. But you are also reducing overall engine efficientcy, right? Miles per gallon are also being sacrificed for low emissions. Higher temperature means higher cylinder pressure per gram of fuel burned.

But I could be wrong...

 

[brianl703]

I have read that EGR reduces pumping losses by reducing intake manifold vacuum for a given engine load and therefore increases fuel economy.

Pumping losses are defined as the resistance encountered by a downward-moving piston against intake manifold vacuum.

If the intake manifold vacuum can be lowered by the introduction of inert gasses which do not participate in the combustion process, pumping losses are reduced.

 

[tom slick]

Here is a link ffrom www.autoshop101.com that explains the function of the EGR system if you would like to learn more.

 

[brianl703]

quote:

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Originally posted by chas3:
some engines dont have an egr system. the cam overlap is used to let some exahust gases back into the cylinder. nice eh?

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Funny story about that..my brother bought a 1993 Ford Escort (he needed cheap transportation). I was looking under the hood and I saw two unconnected electrical connectors which I knew (from having worked on other Ford models) are for the EGR sensor and vacuum regulator (I could tell by the shape of the connectors).

But I couldn't find the EGR valve, it's sensor, or the vacuum regulator. I started wondering if someone had ripped all of the EGR system out..but the computer wasn't giving any error codes nor was the check engine light on.

I finally found out that only California models got the EGR valve. 49-state models didn't need one.

 

[JohnBrowning]

Most modern cars with cam phaseing do not need an EGR and do not have one. My Camry is ULEV II and it does not have an EGR.

 

[brianl703]

Ford installed variable cam timing on their 2.0L DOHC Zetec engine, but only on the exhaust cam.

This was done to eliminate the need for an EGR valve.

 

[eljefino]

I wonder this:

Since the EGR relies on a certain amount of exhaust backpressure, would too much backpressure lead to too much EGR gas?

Then bubba with his clogged catalytic converter would have a stumbling problem with the EGR open. Eliminate that, and the vehicle runs "better". And he'd tell 100 of his closest friends what a good idea it was.

 

[SyntheticShield]

quote:

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Originally posted by tom slick:
Here is a link ffrom www.autoshop101.com that explains the function of the EGR system if you would like to learn more.

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Man, thats worth saving and printing out. Thanks for that info.

 

[chas3]

egr is typically closed at full throttle. it only operates at partial throttle. exhaust gas is inert and richens the mixture. this reduces detonation and cools the cylinders (lean mixtures burn hotter).

most anecdotal information appears to be from people who removed the egr system after it failed. egr can fail and block (no exhaust gas) or fail and open (leak exhaust gas). of course, people with the fail/open notice more performance/mileage after removing the system. therefore egr is bad.

on a daily driver, (a working) egr is more good than harm. detonation is bad. dont like egr? press the pedal harder.

some engines dont have an egr system. the cam overlap is used to let some exahust gases back into the cylinder. nice eh?

 

[SyntheticShield]

I take it then that the general consensus is to just leave it alone. Which it would have taken a strong arguement for me to disable that system, even if it would benefit the oil.

I can see somewhat the benefits of the EGR system, and legalities aside, from what everyone has posted it doesnt seem like there would be any real good reason to disable it unless it was just bad and one was not inclined to replace it.

I thought it would be an interesting discussion to see both sides of the coin. Again, if there had been enough benefit to the oil and minimal consequences, I MAY have been one to consider disabling it, but I think that the trouble of disabling the EGR system as well as having to somehow get the ECU to not throw a code and everything else, it just doesnt much seem like it would be worth it all.

 

[OdinsRageSS]

my 2001 camaro SS doesnt have EGR. All Ls1 f-bodies 2001 and 2001 dont have EGR system thanks to the switch to the 6.0 liter cam.

 

[brianl703]

quote:

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Originally posted by eljefino:
Since the EGR relies on a certain amount of exhaust backpressure, would too much backpressure lead to too much EGR gas?

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It depends on the mechanism used to verify operation of the the EGR valve.

Newer Ford vehicles sense the pressure drop across the EGR valve, and in fact on those too much backpressure from a clogged cat will often set an EGR code.

 

[mechtech]

I've had a lot of experience at my shop with EGR valves either stuck closed, or decommissioned.
9 out of 10 times, the car would run better, especially at part throttle. It would be much more responsive, because it wasn't mixing burnt exhaust with the air/fuel mixture, and losing volumetric efficiency.
There would sometimes be spark knock at light/medium throttle, when there wasn't before.
EGR is used to reduce peak pressure/temps in the C.C., to reduce oxides of nitrogen [for emmissions].
My present car uses a variable exhaust cam to perform the same function [more valve overlap].
EGR is not there to make your car run more efficiently, or have more power.
You may have to use a better grade of gas if you now have spark knocking. You are gaining back what the EGR stole from you.

 

[JohnBrowning]

One thing to consider. EGR's are so dirty that when they started putting them on diesels we got the CI-4 rateing for oils to try to handle the dirt. That was not enough though so we now have CI-4+. EGR's dump a lot of extra carbon,soot etc... back into the engine that should be going out the exhaust pipe!

 

[SyntheticShield]

quote:

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Originally posted by JohnBrowning:
One thing to consider. EGR's are so dirty that when they started putting them on diesels we got the CI-4 rateing for oils to try to handle the dirt. That was not enough though so we now have CI-4+. EGR's dump a lot of extra carbon,soot etc... back into the engine that should be going out the exhaust pipe!

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This was my original concern after seeing Lubrizol's comments in relation to the EGR and oil TBN. It seemed to me that if the EGR can potentially be so destructive to an oil then why have it.

Im no expert, but it would seem more waste oil and dirty filters would out weigh the effects of not having an EGR. I realize, from all the posts made thus far, that the EGR does more, it just seems that there would be a better way to do this than to sacrifice the oil and end up changing it more often.

Im almost tempted to just see through oil analysis the effects the EGR has on the oil with it functional and disabled.

 

[tom slick]

it's only the polluted air that you breath and acid rain. if you enjoy these benefits of pollution then by all means continue to disable the only pollution controls on your vehicles in the name of marginal performance gains.

when the egr system is functioning properly it has a tiny effect on drivability.

 

[JohnBrowning]

Well basicly all the soy burger eaters out in Calf. keep pushing for tighter emissions on cars. Never mind that they are cleaner then they have ever been and little of the current polution in this country is from them.

It is much more profitable to stickit to the auto industry then to stick it to big business. If you make yourself unpopular with big business as a senator or congressman you do not get the nice kick backs. If they made factorys and power plants meet current Calf. car emission standards I would not be so cynical.

A lot of polution comes to use from Mexico, China, and the burning of rain forrests. I belive cars are about as clean as then really need to be with ULEV and ULEZ II, Direct injection and cleaner diesel fuel etc.... Nobody minds that cows and other livestock produce and release more grean house gas's in AMerica every year then propably all the cars and trucks combinede etc.....

I think testing of all cars and trucks should be mandatory over ever increseing emission standards. SO how I think that keeping the cars and trucks running right would do more then ever increasing the restrictions.

I also think that replanting unused tracks of land with green plants and trees would be a good idea. This is especialy true of all the unused fedral land.

 

[SyntheticShield]

quote:

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Originally posted by tom slick:
it's only the polluted air that you breath and acid rain. if you enjoy these benefits of pollution then by all means continue to disable the only pollution controls on your vehicles in the name of marginal performance gains.

when the egr system is functioning properly it has a tiny effect on drivability.

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I agree, I dont think it has much effect on drivability. However, my original issue was the connection of the EGR and TBN depletion per Lubrizol's comments. Im not necessarily a tree hugger as the term goes, but I also dont see the need to make things worse than they have to be, and IF the EGR is having an adverse affect on the oil of an automobile (for those equiped with them) then which is worse, the added pollution in the air or the added waste oil and oil filters in our landfills and in the ground and so forth. Oil recycling has improved over the years, but there are still a great many that just dont do it.

And as John was keen to point out, cars are a whole lot cleaner than what they were. As well I also agree very strongly that the environmental pollution laws now days are horribly lopsided and it seems that industries are allowed to get away with a whole lot more than they should.

Again, I never intended this to become a political discussion, as per my original post, my inquiry was more to the connection between the EGR system and TBN depletion. I would personally like to see a study of what the increased emissions would be from a vehicle with a disabled EGR vs. oil life and wheter or not it would help extend oil change intervals.

 

[crossbow]

Most of the emissions equipment currently in cars is causing more environmental damage at the sake of reduced smog.

quote:

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Cars and trucks, most fitted with catalytic converters, produce nearly half of that nitrous oxide, the study said. (Other sources of nitrous oxide include everything from nitrogen-based fertilizer to manure from farm animals.)

The EPA study also showed that nitrous oxide is one of a few gases for which emissions are increasing rapidly. Collectively known as greenhouse gases, they trap heat in the earth's atmosphere.

The increase in nitrous oxide, the study notes, stems from the growth in the number of miles traveled by cars that have catalytic converters. And the problem has worsened as improvements in catalytic converters, changes that have eliminated more of the nitrogen-oxygen compounds that cause smog, have conversely produced more nitrous oxide.

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http://www.junkscience.com/news2/catalyt.htm

There are also some articles on www.EPA.gov. The primary issue is that the overall media/population has been so brainwashed into certain beliefs, that its almost impossible to undo the damage thats now occuring due to "over ethusastic" emission controls.

If you really want to get into a debate...just start reading up articles on how recycling is actually bad.

 

[Fuelrod]

Brian, forget "pumping losses" because of less intake vacuum. You have forgotten about the energy lost compressing this useless inert gas..

EGR valves reduce engine efficiency. Even detroit got rid of them when they figured out another way.

Reciprocating piston engines have "pumping losses" but they are NOT related to compression or vacuum. They are caused by the energy lost accelerating and deceleration the weight of the reciprocating parts...