There is always Wikipedia, for what it is worth:

EGR in spark-ignited engines

The exhaust gas, added to the fuel, oxygen, and combustion products, increases the specific heat capacity of the cylinder contents, which lowers the adiabatic flame temperature.

In a typical automotive spark-ignited (SI) engine, 5 to 15 percent of the exhaust gas is routed back to the intake as EGR. 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. The impact of EGR on engine efficiency largely depends on the specific engine design, and sometimes leads to a compromise between efficiency and NOx emissions. A properly operating EGR can theoretically increase 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 minor compared to the first two.

It also decreases the efficiency of gasoline engines via at least one more mechanism:

Reduced specific heat ratio. A lean intake charge has a higher specific heat ratio than an EGR mixture. A reduction of specific heat ratio reduces the amount of energy that can be extracted by the piston.

EGR is typically not employed at high loads because it would reduce peak power output. This is because it reduces the intake charge density. EGR is also omitted at idle (low-speed, zero load) because it would cause unstable combustion, resulting in rough idle. The EGR valve also cools the exhaust valves and makes them last far longer (a very important benefit under light cruise conditions)

 

Hahahaha
All you EFI guys arguing over stupid stuff.

Carb>EFI

 

Sorry, did not intend to claim that as my own, that was cut and pasted, as with the EGR summary for spark ignited engines from Wikipedia above.

It seems that a properly designed and functioning EGR system has distinct advantages to engine performance and longevity, in addition to NOX reduction.

Now, are Toyota systems properly designed? And are they functioning properly after 200k miles?

Never even thought about that system until this thread, now I am reading up on them all over the web.

Interesting stuff.

 

Anyone who says "22re egr gains performance" in one sentence is a moron. Only reason I removed my egr was due to it not working and the lack of emissions up here. Fixed my idle to.

 

I like this thread

I'm amazed no one suggested water injection to reduce nox like we use on our gas turbines at work!!!

Actually I know it wouldn't work on a piston engine so don't flame me...

 

As a matter of fact it does work on a piston engine, as long as its in moderation. I'm using a 50/50 water mixed with methanol, not for nox reduction but for cooling intake temps and reducing ping.

Aquamist 2d system: http://www.urdusa.com/index.php?cPat...fmpquj203jsmd7

 

haha,

Like I stated, WoW, it made a difference on my truck, not in top end, but idle, and mid range HUGE difference, the reason is simple, mine was broke and on my high milage vehicle it was KILLING the truck, it would Stumble bad from off idle to about 3k, then if you were driving, and hit that "sweet" spot, it would feel like it was going to die.

Hard to explain, but Holy balls Batman, it made a huge difference on my truck, HUGE.

Still makes alot of noise and goes nowhere above 3200, but below it is whwere I drive 90% of the time and it's where it is very noticable.

I run Water Meth on my car as well, a Snow kit and it works GREAT, run 17 degree's of timing without it, 24 degree's with it, about 90 hp difference At the Wheels

 

Thanks man, will do that T this afternoon as I have the needed stuff, hopefully I can get this temp light to go off - truck is staying in normal operating temp, just sure I have air in it due to the light being on

 

Baha the EGR valve is closed during these times where you say performance has increased lol. I think you might be suffering from "I made a modification it must be better". The mind is a very powerful thing...

 

BAH, WTF is that, no, it's not Closed if it is Malfunctioning and STUCK Open.

I think somebody read someone elses word and doesn't know his butt from his head unless someone tells him.

Trust Me - 12 years of military service active duty AF, now in the Reserves, the majority of that time in Mechanic's and I know my .

The truck runs EXTREMELY better during the time that your talking about, which is the time when a functioning EGR would not be dumping gasses in the intake, however, MINE WAS STUCK OPEN, therefore removing it added the lost power back and increased DRASTICALLY driveablility.

However, you belive everythign you read on the internet and say my Butt dyno is telling me it increased, sorry buddy, your Wrong, plain and simple. If your EGR is functioning properly, you wouldn't notice, however mine wasn't so it's a HUGE difference.

But while your at it, and you know it didn't make any difference on my truck because you read it somewhere, did you know that Al Gore invented the internet?

 

Could have ended with this.

 

I see this thread getting out of hand very quickly...



why does the "EGR Thread" always come to this...

 

Not all EGR threads. Just the EGR removal threads. My EGR thread is wholesome and family oriented.

 

okay fine, correction:



Why to all EGR removal threads come to this?








you know what I meant...

 

Al Gore invented the Internet ? haha good , I guess he can add that to his harvard degree, his vice presidency, his joint nobel peace prize and his academy award...I laugh every time I hear that but, It is amazing how out of context a quote on CNN can get.

I missed the point where you said it your EGR was malfunctioning prior to removal...In that case welcome to the world of stock performance. Your truck is one step closer to running like how it was designed to.

 

hmm. higher numbers after removing the EGR.

 

the difference is obvious, not to mention lower EGT's

 

Unless your EGR was stuck open like the OP this dyno is rubbish. What are the power figures representing anyway? As has been made clear a working EGR is closed at WOT. There is no extra performance available unless there was a faulty EGR system in the first place

 

Cool cool,

I was a little pissy yesterday, been on this board around 6 years and never did any post like that response, sorry if it was a bit offensive - just get that way occasionally I guess.

 

Hi , this worked for me too , now the idle is more stable and the flat spot on the acceleration is smaller , thanx for posting this, i did mine blocking both ports with soda can material and felpro gasket.