EGR System Facts

[mrnickleye]

Many of you want to know about EGR systems. Can you remove it??
Can you pass smog if it is removed? What would happen if it is removed??

If you are smarter than the engineers that built the car? Is there life on Mars?? What's for dinner?? ETC. ETC..

Well...you can not "legally" pass a smog test without ALL the original smog equipment on the car, and working. Catch word here..."legally".

Here are some good articles on EGR Systems.....

http://www.garage-pak.com/pat-goss-w...revention.html

http://www.misterfixit.com/egrvalve.htm

http://www.autoshop101.com/forms/h61.pdf

http://www.asashop.org/autoinc/dec97/egr.htm

Now get back out there and burn some rubber !!!

[Strannik]

well as i said in the original thread it came:
depends on where you are.
supras only had EGR in Europe and US
it really depends on the emission laws in you particular place

here is some info from supras.nl:

First thing to remove is the EGR cooler. I assume you won't put it back on your car, unless you live in California and you have to pass the yearly emission checks. Over here in Holland you will pass without the EGR system, so this is a good idea. You really don't need the EGR system and removing it removes weight from the vehicle as well. And that's good for you gas mileage, so saves the environment! Yeah right ;-) Note the EGR system only limits the NOx gasses on idle. It does not help CO, CO2 or CH emission checks. In the Netherlands, cars before 1992 must only pass CO checks, so the EGR system is not needed here. Please check how this applies in your country before removing! An other arguments for removing the EGR system is preventing the intake manifold from getting black on the inside (bad airflow after loads of miles)

So yes - you can be smarter and remove it. JDM supras run w/o it from factory.

From experiences of various supra owners the only place where you do need EGR to pass emissions is California.

[mrnickleye]

Quote... ^^^^
You really don't need the EGR system and removing it removes weight from the vehicle as well. And that's good for you gas mileage, so saves the environment! Yeah right ;-) Note the EGR system only limits the NOx gasses on idle.

Reply....

A six pack of beer weighs more than the entire EGR system, so NO better fuel economy gained.

The EGR system DOES NOT operate at idle. Please read and learn from the sites listed in my previous post.

A properly functioning EGR system WILL help comtrol engine pinging under load conditions. (I run 15* timing)

But of course pinging can also be controlled by:

1) Stay off hard accelerations (why have a supra, then)
2) Run premium fuel, and probably octane booster (cost more $$ to drive)
3) Set the timing back from 10* to 5* (or even 0*). (= Poor MPG)
4) Knock sensor detects ping, then computer retards timing (=poor MPG)

And what is the purpose of the EGR anyway??? It lowers the peak combustion temperatures, which helps prevent the creation of NOx, (which kills the air). And Thus Cleaning up the air WE breathe.

Without pollution controls the air will become so polluted, WE (animals) won't be alive more than another 100 years. Of course all of us reading this will be dead, but what about our children??

[Strannik]

let's talk technical, don't bring greenies in here
if you care about enviroment so much as they do you shouldn't be driving performance vehicle

now back on topic:

1) You seem to be ignoring my point that JDM supras don't have EGR. I'd like to see some explanation to that.

2) EGR decreases the combustion chamber temperatures, which is decreasing the power and MPG

Confirmation is on the website you list in links:
http://www.misterfixit.com/egrvalve.htm

The automotive engineers figured that they needed to do something to lower the peak combustion temperatures which only occurred under certain high load driving conditions. They figured they could do so at the expense of power and fuel economy but what the heck, ya can't have everything! If they could only add something to the combustion chamber that would act like sort of a fire extinguisher to cool the combustion temperatures that would do it.

So it's a catch 22 - whatever you do you lose performance. In this case i would get rid of EGR just because it's another part that can go wrong.

3) Yeah i agree, it doesn't operate at idle, i was wrong here.

4) Here is the quote from another website you gave:
http://www.asashop.org/autoinc/dec97/egr.htm

Even if the car appears to run well, excess smog is being produced. An EGR failure will not only cause excess NOx, back up strategies will often entail enriching the mixture or retarding the timing. This in turn increases HC and CO emissions. Even if you don't see it on a 4-gas exhaust analysis test, the emissions are being created and the catalytic converter will not always cover them up.

If you can't see the difference on analysis then what's the point of it?

Bottom line is: the only place where you will not pass the test w/o EGR is California. Main reason why people remove EGR is because it causes carbon build-up on the intake.

Please comment on JDM supras not having EGR

[mrnickleye]

As for this quote:
Even if the car appears to run well, excess smog is being produced. An EGR failure will not only cause excess NOx, back up strategies will often entail enriching the mixture or retarding the timing. This in turn increases HC and CO emissions. Even if you don't see it on a 4-gas exhaust analysis test, the emissions are being created and the catalytic converter will not always cover them up.

The author is talking about OBDII cars, 1996 and newer. MKIII's are OBDI systems, and the computer does not compensate for lack of, or excess EGR.

As for passing a smog test....it is illegal to tamper with, disconnect, remove, modify, disable, etc. etc. any pollution control device that was originally installed by the manufacturer. That is a federal law, applicable to all 50 states. Some states (which could be many) do not require a visual or functional inspection of the devices.

But as I said, it all comes down to the test facility/technician.

Every vehicle that is allowed to be sold in USA must pass EPA tailpipe emission testing. Many new(er) vehicles don't have EGR systems because they pass the EPA tests without it.

As for "pinging" ....I don't know what the recommended timing is for JDM engines, it could be less than 10*. Also, the computer may not advance the timing as much as USA/European. Or it may retard the timing more, and quicker, to keep pinging to a minimum.

My owners manual states that "some" pinging (light engine knock) is OK under acceleration, or going uphill. I personally don't like that.

I don't know what Octane rated fuel is recommended for JDM either, as 87 octane is the min. for USA. (for better performance it says 91 octane)


As for EGRs not on JDMs....manufacturers won't spend more than they have to on pollution controls (or many other things either). A $ saved, is a $ earned, X a million cars = a million $$$....It is how they think.

All combustion engines pollute the air. Some countries allow more pollution than others. Manufacturers save millions $$$ by not having to install some pollution control devices.

Laws change. During the years of our cars, laws allowed higher levels of pollution. That is why EGR systems were not on many brand cars in certain countries. The cars met (tested below) the higher allowed levels.

Cleaner intake manifold passages is one result of not having the egr.

Also, higher peak combustion temps create higher engine temps, especially in the head. These cars already have enough over heating, and headgasket problems.

[mrnickleye]

I'm certain that those people that are doing some intense mods to their engines will be focusing on the best solutions, using 'fuel management' systems, and such, and thus can easily remove the EGR system and have no running problems.

But...to be a guy that opens the hood and rubs his hands together, and says "what can I remove today" ? Well, he just needs to do some research first.

Its like throwing a K&N filter on, and expecting to gain 20hp.
Ain't gonna happen.

[mrnickleye]

High NOx is an indication that the EGR system is not working properly. Very possible that the vacuum hoses aren't hooked up properly, or the passages are plugged with carbon, and not allowing exhaust gasses to flow into the intake to control the NOx.

The EGR valves are very tough, and usually don't go bad. They could be plugged up with carbon. The transducer (back-pressure sensor) above the valve does go bad.

You can check some of this out yourself by un-plugging the vacuum hose to the EGR valve while the engine is idling, and use a longer piece of vacuum hose (keep it in your toolbox for future uses) to plug onto the EGR and suck on it with your mouth.

If the EGR valve is working, and the passages aren't plugged, the engine idle will fall right off, and possible kill the motor. If this happens, then your transducer is likely bad. Dealer only part.

If you can't hold the vacuum with your mouth (cause air comes thru) then the valve diaphram is bad, and the valve won't open.

If the idle does not fall off, and the valve seems to hold vacuum, (suck and release quickly with your finger on the valve, you should feel it snap shut), then you can remove the metal tube from the valve to the intake manifold, then try testing again. If you get loud exhaust coming out of the valve, then the passages are plugged in the intake manifold, and must be cleaned out.

The passages may be plugged before the valve, in the EGR cooler. Hope not, as it will be a bitch to remove the cooler and clean it out. Check by removing the EGR valve and starting the motor to hear if exhaust comes out the hole.

[mrnickleye]

Here is a blowup of one of the places to clean out some of the carbon build up.



Remove....



http://www.cygnusx1.net/Supra/Librar...re=1703&Page=1

Cover #17864
Clean passages in intake manifold with a coat hanger and carb spray.

http://www.cygnusx1.net/Supra/Librar...re=2501&Page=1

Tube #25601
Cooler #25681 (a real bitch to do)
Valve #25620

Clean holes in head too, you see them in picture...

[shiftysupra]

Originally Posted by mrnickleye

I'm certain that those people that are doing some intense mods to their engines will be focusing on the best solutions, using 'fuel management' systems, and such, and thus can easily remove the EGR system and have no running problems.

But...to be a guy that opens the hood and rubs his hands together, and says "what can I remove today" ? Well, he just needs to do some research first.

Its like throwing a K&N filter on, and expecting to gain 20hp.
Ain't gonna happen.

Would have to agree here. No point in taking it off unless you have your cooling system upgraded and top notch. Your just putting more stress on your head. If gaining about .1hp means that much to you go ahead and blow a head gasket.