About EGR system removal benefits

[clintnixwood]

Hello, I was reading up about EGR (exhaust gas recirculation) systems, and was wondering if other people have removed it from the U.S. spec 4a-ge engines and if it actually benefited power. From what I read, in some instances it helps efficiency and power but in most cases it decreases peak power.
Does anyone have experience with this, and the results?

[90 GP]

Don't know about the power aspects gain but good luck passing emission testing if you have it in your area once it's removed. Not to mention with dealing with pinging issues too.

[SCT]

My theory on this, the motor would have to be tuned down to pin point so ALL gas is burned in order to do an EGR delete and gain some power. By doing an EGR delete alone, any unburned gas that collects in the exhaust system could ignite and MAY interrupt the flow of exhaust which decreases some power.... just my theory.

But the main factor for having an EGR is so the world can live longer. I can care less, the world is not going to go haywire any time before I die. Give our next generation something to figure out and do.

I'd keep the EGR and work with it. $4+/g at the pumps is what I'm more concerned about.

[Blof-fan]

Have any of you ever opened up the intake manifold of a EGR equipped 4A-GE?
Well, I have and I was shocked how poluted the walls of the manifold were!
I sandblasted the whole thing and you would not believe how much effort it took to get the inside of the intake clean again. I figure there was at least 5mm's of pure, black grutt on the intake walls.

Now, I don't know about you guys. But I like the intake side of my engine nice and clean Fresh air going in, exhaust gasses going out.
Why on earth would you want to redirect exhaust gasses into you intake and thus partially suffocating the engine?

(Yeah, yeah...enviroment etc, etc.) But the 4A-GE is a 'performance' engine. If you want to save the enviroment...buy a Prius!

I do not think deleting the EGR system will have negative results on poweroutput. You will get more frech, combustable clean air into your engine, which is always a good thing. You will help keep things clean on the intake side (Another reason to always mount a oil catch can in your car as well).

By doing an EGR delete alone, any unburned gas that collects in the exhaust system could ignite and MAY interrupt the flow of exhaust which decreases some power.... just my theory.

Here in Europe, practically none of our 4A-GE's are equipped with a EGR system and I can tell you that we have never experienced unburned gasses in the exhaust system. So I guess there is a pretty small risc to that.
When people are afraid of pinging (Which we also never experience on our engines) Just put higher octane fuel in your car. (With a engine like a 4A-GE, it is always a good idea to fill her up with a good octane fuel. They run much nicer on it!)

But why are you guys so afraid of 'gas' issues anyway? The EGR system doesn't work on idle and full throttle. So there would already be issues there if there were any. And even then. The EGR system is designed to lower the temperatures in the combustion chambers by making sure there are some unburnable gasses in there along with the combustible mixture. (So you are in fact smutthering your engine, bringing performance down)

I would be more afraid for unburned fuel entering my exhaust en frying my cat WITH the EGR system than I would be without. Less fresh air but a even amount of fule going into the cylinders makes the engine run rich (cooling down temps even more) and could cause unburned fuel entering the exhaust end igniting there

And then another thing people usually don't think (or even know about). To get back to that poluted intake manifold: Did you know that the shapes inside yout manifold are carfully tuned to help your engine breathe better at certain RPM's? What do you think will happen when that gets interferred by with a thick, black, bumpy crust of crudd?

All in all: I removed the EGR system of my US spec 4A-GE...haven't ran her yet, but my guess is it can only improve

[clintnixwood]

Thanks for all the discussion guys, this is important, as everyone has different experiences with these kinds of things.
It is important to note all the aspects, the negative effects it could have, as well as the positive.
On a side note, I always put premium octane gas in both cars I have; yes it costs a bit more but the price is not that noticeable, but is worth it for an engine like this.
I also have a 91' Mitsubishi Eclipse GSX, which is a turbo'd engine, and its 2 liter 4g63 engine is also pretty famous, like the 4a-ge. That engine also has the EGR, and a friend of mine who is really big into the eclipses had rebuilt his engine himself, and he had removed it, basically saying the same thing, that it dirties up the intake, and can potentially be the source of a number of issues in older engines. So far the removal hasn't caused any issues in that engine, but he's got a number of different mods and problems to work out because of those mods, so that is another story entirely.
What I wonder is if the ecu programming is affected by the EGR, if it was taken into consideration for engine timing and other programming?

[verlaryder]

"and can potentially be the source of a number of issues in older engines."

Would the Toyota engineers agree? Would members of the Toyota 400,000 mile club agree?

I've never known a member of the Toyota 400,000 mile club that deleted their EGR.

[Blof-fan]

I wouldn't say a egr system would lead to any problems directly. But it's a fact that power output decreases with age. A egr system could very well speed up that process. The engine might run flawlessly, but it won't turn out the power it used to.

[clintnixwood]

Notice I said the word 'potential.' I'm not really trying to spout out a bunch of stuff, because really I don't know that much. What I do know is that cars of this generation have idling issues as they get older. My mechanic tells me that it is because fuel injection was 'fairly' new technology at the time. I've actually run into this problem to various degrees with both cars I own. Of course, the problems are caused by a number of different things. Believe me, I researched for a long time as to why my Eclipse was idling roughly, and what came up was a 100 different reasons; there wasn't an exact pinpointed issue. I tried different reasons, and came up with a certain conclusion that might be the right one (the isc driver on the ecu is probably burnt out).

It is possible that the EGR adds to these problems, but I suppose the simple answer would just be to clean the intake manifold over time.
The thing is, putting dirty exaust gasses back into the intake just doesn't sound like a good thing. With the advent of hybrids and fully electric cars, you can see that the market is moving towards cleaner emissions. So I'm not really concerned with my little corolla that will put out 5-10% more exaust gasses. But that is just me.

[eage8]

my JDM silvertop doesn't have one and I like it that way...

only the california spec 4A-F has one, the federal version doesn't, it's not for anything except reducing NOx emissions.

[verlaryder]

My California 4AF with 287,000 miles still idles smooth and the EGR system has never been touched.
Ditto my California 22RE Toyota pickup engine with 486,000 miles.

I keep the engines tuned to the way they were when they left the factory using Toyota tune up parts which keeps potential carbon clogging emissions low, hence the EGR valve and pipes don't become clogged.

[clintnixwood]

Both cars I own, I purchased pretty recently. I've had the eclipse for two years, with 150,000 miles when I got it. I know the person took care of it at least moderately, when I took the throttle body off to clean it, it was sparkling. But that engine is known to have a couple of issues later in its life, like idle trouble, and the valves start ticking and need to be reworked.
The corolla I purchased from a guy who works at Toyota, and bought it for his son, but it ended up not being used very much, and so it had 116k on it, which is pretty good for a car 21 years old. He took really good care of it, except for a couple of things, which is understandable. But every car owned sees different kinds of situations, and its hard to know about things when other people have owned them.
I suppose if your engine still runs pristine at 400k then you don't use it for sport, just moderate driving, eh? I'm actually a delivery driver, which tests engine parts fully; lots of idling, starting, stopping, and city driving. The corolla is a fun car for that though, decent gas milage while still being peppy.
Perhaps you could say certain things, like how a toyota engine will run forever, but it is still an engine, and certain things need to be replaced, especially if you drive it intensely. That being said, most people don't take absolute care of their cars, even if they do baby it. Stuff builds up, and I know most people don't have the extra money or know-how to keep it in perfect condition.
Perhaps in a couple of years, when this car is not my daily driver, I'll actually get around to removing the EGR. But for now the Eclipse is my project car, although I do love these high revving, NA engines.

[Mr.Nutcase]

EGR lowers the engine combustion chamber temperature.
Toyota has removed EGR systems in newer toyotas(in 2002 and up)
Reasons? Why EGR systems build up with carbon....
They are using Variable Valve timing-Intelligence( VVT-i)
Toyota engine that have VVTi are 1zz-fe, 2az-fe,ect..

[eage8]

Originally Posted by Mr.Nutcase

EGR cools the engine by lowering combustion chamber temp.
Toyota has removed EGR systems in newer toyotas
Reasonm they build up with carbon....
They are using VVTi
It is called Variable Valve timing- intelligence..
Engines like 1zz-fe, 2az-fe,ect have VVTi

Your whole post does not make any sense... Use complete sentences...

[Mr.Nutcase]

Originally Posted by eage8

Your whole post does not make any sense... Use complete sentences...

If you dont understand, you will never understand...
VVT-i has replaced The EGR system.

[clintnixwood]

If they have, then it makes sense, to use better technology. Even American brand cars are (finally) getting better engine technology. Camaro and Mustang v6 engines are examples of that.
On a side note, I got the Eclipse up and running, and took it around the block a few times. Torque feels nice but it somehow seems like it lost its peak horsepower, but there are a number of reasons that could be with turbo. Eventually it's going to get a complete rebuild.