rdharper

Wow... correct twice in row. And in fact, a properly working EGR system will actually improve engine efficiency contrary to popular assumption.

MudHippy

Didn't even bother to gather any FACTS to prove that, did ya? Or, perhaps it's that you simply disagree, with my sources? Because I'd be more than happy to give you several GB's more scientific arguements that DIAMETRICLY DISAGREE.misterfixit.com/egrvalve.htm I have assumptions all right, concerning lack of proper use of the scientific method, that runs RAMPANT, like a scourge upon my intellect.THANK YOU AND GOODNIGHT!

rdharper

Understand that no one has more contempt for the wacko environmentalists that do I (believe me on that one).

But here is the argument (from wikipedia).

EGR in Spark-Ignited (SI) Engines

In a typical automotive SI engine, 5 to 15 percent of the exhaust gas is routed back to the intake as EGR (thus comprising 5 to 15 percent of the mixture entering the cylinders). The maximum quantity is limited by the requirement of the mixture to sustain a contiguous flame front during the combustion event; excessive EGR in an SI engine can cause misfires and partial burns. Although EGR does measurably slow combustion, this can largely be compensated for by advancing spark timing. Contrary to popular belief, a properly operating EGR actually increases the efficiency of gasoline engines via several mechanisms:

Reduced throttling losses. The addition of inert exhaust gas into the intake system means that for a given power output, the throttle plate must be opened further, resulting in increased inlet manifold pressure and reduced throttling losses.

Reduced heat rejection. Lowered peak combustion temperatures not only reduces NOx formation, it also reduces the loss of thermal energy to combustion chamber surfaces, leaving more available for conversion to mechanical work during the expansion stroke.

Reduced chemical dissociation. The lower peak temperatures result in more of the released energy remaining as sensible energy near TDC, rather than being bound up (early in the expansion stroke) in the dissociation of combustion products. This effect is relatively minor compared to the first two.

EGR is typically not employed at high loads because it would reduce peak power output, and it is not employed at idle (low-speed, zero load) because it would cause unstable combustion, resulting in rough idle.

Post away if you have a good argument as to why those three arguments are not correct.

MudHippy

NOPE NICE TRY! I'll let what you posted there stand on it's own. It actualy doesn't approach logic, quite discernable on it's own. And, that it happens to be apparent to those..... No, caught my self, hey, believe what ya like. But, only believe half of what you read, and nothing your told.Thanks.

rdharper

Not an argument there young feller. Try again.

MudHippy

I was trying not to. I'm happy to say you win. I feel secure having represented my partys' point of view. Down with propaganda, and down with that southerly state that keeps my home ever-overpopulating.

84sr5yoty

I bypassed the EGR in my 84 11 years ago and it pinged under moderate to full acceleration. I also logged my fuel mileage and nothing was gained. Reconnected the plugged vacuum line and the pinging went away.

Toyotas EGR design was ahead of its time back then and was very efficient and effective. Take a look at vehicles 20 years later and you'll see that they use the same setup

Now, the first generation EGR setup in my old 1973 Dodge Dart was a WHOLE different story....and yes, it was bypassed.

rdharper

I win?

Then I'll switch sides. The fact that no performance engine, ie: race cars etc. use an egr suggests they don't pay for themselves, performance-wise. Do I win again?

MudHippy

That's what we call anecdotal evidence. Here's some more, my 3vze runs better without an EGR. Measured in MPG.

MudHippy

? uh, thanks, I geuss, is this gonna be fun bein' on the same team, you and me? I mean now what? I dunno? No rival, defeats the purpose kinda does it not?

rdharper

Maybe if we are both right? I'm an empiricist by nature and experience, with a heavy emphasis on applied statisical analysis.

In that vein, we've had four reasoned arguments (mine) but no data from either side, despite a threat on your part to provide gigabytes of data, if memory serves.

Despite my arguments on both sides, truth is I do not know which arguments are correct despite the elegant presentation.

I suspect, however, at this point, that the egr can in fact improve a current stock engine design (slightly) over no egr, if correctly running.

I also suspect that the complexity of all these emission control devices are making it difficult to design, build, and maintain most vehicles. It could well be that the net effect of these devices have added to the country wide energy pollution, despite the improved air in California where testing forces most people to maintain correctly running systems. But that is pure speculation, as you know.

Kyle95sr5

My egr valve isn't working so I unplugged it. It runs waaaayyy better, but I do have pinging at higher rpms. I'm not up for buying a new egr valve, so ill deal with it until I can find a nice used one.

MudHippy

Well, venerable one , I appreciate compliment. I was starting to get a little worried. Those gig's would be a long time coming, if I could infact pull that much out of a certain bodily orafice. I aspire to become much like the. And, perhaps, if I ever attain such status, I'll have acquired the "Holy Grail" of EGR performance data we have vested such interest in. Thanks for takin' it so easy on me there.

4Runner92sr5

well crap i didn't know a simple question was gonna errupt in debate. But i will say that Hippi makes a valid point on with his sources and research. The egr dumps back into the intake what should be going out in the air. Yes thats not soo good emissions but your engine is cleaner therefore lasts longer am i correct?? I lived in CA for 16 years before i moved here and the emission controls that we had there were rather contradictory. First gasoline was more expensive because it had to be refined even further then needed therefore robbing gas mileage. If your car gets worse gas mileage then your burning more fuel anyway you get the hint. Before i moved i was gettin 11 mpg then i moved here to NC where there are much much less controls on emissions and i now get 15 before i changed anything to my engine. This obviously doesn't go for newer trucks because there engines are engineered far more superiorly then our 3VZE but if you look at the CA models from the rest of the models all those extra emission vacuum lines kill gas mileage compared to the rest of the models. Now all of our engines on our 2nd gens have an EGR system but if you look at this pic i believe post 19 on https://www.yotatech.com/forums/show...ht=egr+removal
You will see what is getting dumped back into your engine. Now even a mechanically DEclined person can figure out that ˟˟˟˟˟ doesn't look to good. I removing my EGR not only because i have a 92' and i don't have to get smogged anymore but because of the carbon going back into the intake. And if your going for greenhouse gases heres a quote supporting that yoru emissions don't change but might even be better this is a direct quote from Epic Ed on another thread
"Gas mileage has been about the same if not better. I had to go through emmisions testing to renew my registration last month and was worried that it might cause me to fail, but my emmisions turned out better than my previous test in '03!"
All in all we have our opinions on this subject i hope i have pretty much made mine clear that SOME of these emission control lines on our vehicles can be contradictory and not necessary.

AUYota

How dare there be an arguement and I'm not invited! lol

To me it's obvious that a NEW/Working EGR under 80k miles or so is better than no EGR used at all- but no EGR valve is better than a broken or old one, such as mine over 230k miles.
Lets say your truck gets 20 mpg. From an environemental aspect a vehicle with 20 mpg with an EGR is better than a vehicle with 20 mpg and NO EGR (NOx). That said if you have an old EGR that hinders your mpg to 12 mpg (as with mine) and disconnecting it gets you back up to 18+ you are probably better off unpluging it NOx concerns aside. However, I'd stop short of sawing the EGR off. A brand new valve is 150 bucks and prob 20 bucks at a junk yard. This isn't a "cheap" hobby and if you have a green streak down your back like myself that wouldn't bother you.

I've said this before... Off Roading as a hobby is at a serious cross roads. IF we embrace environmental concerns into our past-time it will survive, if not it will die. That's all... I strongly discourage removing your EGR's and think it's akin to not following tread lightly regulations which YT supports.

AUYota

Also... If I take the EGR valve off an soak it in acetone will that clean it and keep it from staying open or closed, which ever the case, which I believe is the problem...

MudHippy

Duly noted, a tad hypocritical, but duly noted all the same. I like arguing Well, I never claimed to be a comedian. With a little post-editing , I can warn future readers. What I wish I'd said here was, I too have concerns associated with harming my habitat, and that idea ya got there, ain't such a bad one at all. And, yes I know what you meant by which ever option one chooses should be the one causing less total emmissions, theoreticaly. I feel as though I shouldn't potentialy cause any more undue bad feelings, by posting my response in the typical manner. I don't really deserve clarification on matters, anyway.Terrible ain't I.

AUYota

not hypocrictical at all... There is a good that the EGR does and this is reduce NOx. However, If using a bad one demotes your MPG to 40% as mine did, then the added carbon footprint your vehicle has from going from 20 to 12 mpg more than offsets what good elliminating NOx does.

MudHippy

That was no jab at ya, bro. Lord knows I've no footing from which to launch one. I could very well be mistaken by your wording there. Let me extract..."That said if you have an old EGR and it hinders your mpg to 12 mpg(as with mine) and disconnecting it gets you back to 18+ you are probably better off unplugging it NOx concerns aside." It sorta conflicts with the notion of putting such behaviour in line with the paramount concerns regarding treading lightly. No offense meant by that at all, my apologies.

AUYota

I guess I should add... IF all you can afford to do is disconncet the EGR until you got the bones for a new EGR valve then disconnecting it and getting 18 mpg instead of 12 is a better move in regards to the environment- the NOx doesn't balance out the detriment that a 12 mpg vehicle does...

Keep in mind the best thing is to have a working EGR valve over removing it.