EGR ???
- Thread starter maitai69691
- Start date
it doesnt recirrculate the half burnt gasses back into your intake manifold and send them back into your motormaitai69691 said:
I don't know how many times I've said this, but it's LOTS.IwantMKIII said:
Either explain what terms to use in the Search feature, or don't post. The search police aren't welcome here.
Ideally, you should provide the search terms and a link to the appropriate threads that finds.
The result of my method:
- A new user who learns how to use the search
- A thread that actually has useful information in it for future reference, both on searching and the subject at hand.
The result of your method:
- A new user who is disappointed for being chastised, and STILL has no real idea how to find the information they are looking for.
- A useless thread that anyone in the future who is looking for EGR removal information will find, read, and discard, because the information they need isn't there.
- Me chewing on your ass. You don't want me chewing on your ass.
PS: Start reading here: http://www.supramania.com/forums/showthread.php?t=19330
Search terms were "EGR AND removal" - I ignored the first three returned threads, (one of which is THIS thread), and the other two were obviously not what I wanted as well, and opened this thread: http://www.supramania.com/forums/showthread.php?t=55862&highlight=EGR+removal
The second post in that thread has the link I just posted.
Search terms were "EGR AND removal" - I ignored the first three returned threads, (one of which is THIS thread), and the other two were obviously not what I wanted as well, and opened this thread: http://www.supramania.com/forums/showthread.php?t=55862&highlight=EGR+removal
The second post in that thread has the link I just posted.
hey thanks alot it was just a basic quick ??? because im learning about them in school at UTI and from what i know they dont do you any good but maby better fuel ecanomy and do or very little HP loss just woundering so what the point.but thanks for the help.
Adjuster
Supramania Contributor
I second that assesment Jetjock 
EGR is/was used to reduce unburned HC's and in some part, allows poor engine designs to deal with crappy gas while still running more static CR than they otherwise could. (The recycled exhaust gas dilutes the intake charge, reducing the possibilty of knock/ping.)
It only works under certain conditions too, and it should not be open all the time. (Yet they often fail "Open" on older cars due to excessive carbon build up..)
They cause the rear of the head to run hotter as a result of the exhaust gas being routed through the "EGR Cooler", the plate deal on the back of the head.
Some are for keeping them, some are against, and others remove it to make space or clean up the engine bay, but in many places, they will want a working one for your car to pass the smog inspection. (Think California, and other socialist states in this world of ours.)
My Supra has not had one for years with no ill effects, but then again, it worked fine when it was on the car for years too, so draw your own conclusions...
EGR is/was used to reduce unburned HC's and in some part, allows poor engine designs to deal with crappy gas while still running more static CR than they otherwise could. (The recycled exhaust gas dilutes the intake charge, reducing the possibilty of knock/ping.)
It only works under certain conditions too, and it should not be open all the time. (Yet they often fail "Open" on older cars due to excessive carbon build up..)
They cause the rear of the head to run hotter as a result of the exhaust gas being routed through the "EGR Cooler", the plate deal on the back of the head.
Some are for keeping them, some are against, and others remove it to make space or clean up the engine bay, but in many places, they will want a working one for your car to pass the smog inspection.
(Think California, and other socialist states in this world of ours.)My Supra has not had one for years with no ill effects, but then again, it worked fine when it was on the car for years too, so draw your own conclusions...
to go a little more in depth
egr works because it reduces the oxygen concentration of the intake what this does is lower the peak flame temperatures in the clyinder note that i did not say reduces heat rejection
by lowering peak flame temperatures you lower the change of a uncontrolled combustion event hapening infront of the flame this is merely a side benefit and not what egr was intended for.
egr lowers nox emmissions by a large amount. why is nox reduction important because catalysts dont reduce nox pretty much at all. your catalytic converters deal with mainly the HC emissions from the engine the nox is left for the most part untouched. nox emmisions are directly tied to the temperature of the charge inside the cylinder and the peak flame temerature during combustion. by diluteing the combustion you lower the peak flam temperature thereby reducing the NOX specis in the combustion.
long story short if you remove it remove the cooler as well and put a block off on the back of the head so no egr gets in the cooler
will you notice any side effects NO
will you notice any benefits only that of a cleaner looking engine bay and maybe a cold rear of head
egr works because it reduces the oxygen concentration of the intake what this does is lower the peak flame temperatures in the clyinder note that i did not say reduces heat rejection
by lowering peak flame temperatures you lower the change of a uncontrolled combustion event hapening infront of the flame this is merely a side benefit and not what egr was intended for.
egr lowers nox emmissions by a large amount. why is nox reduction important because catalysts dont reduce nox pretty much at all. your catalytic converters deal with mainly the HC emissions from the engine the nox is left for the most part untouched. nox emmisions are directly tied to the temperature of the charge inside the cylinder and the peak flame temerature during combustion. by diluteing the combustion you lower the peak flam temperature thereby reducing the NOX specis in the combustion.
long story short if you remove it remove the cooler as well and put a block off on the back of the head so no egr gets in the cooler
will you notice any side effects NO
will you notice any benefits only that of a cleaner looking engine bay and maybe a cold rear of head
supraguru05 said:
That pretty much covers it. If you want to remove your egr and COOLER, the only way I know how is taking off the head. I did it by tapping the hole that comes out of the cyl head and put some alluminum plugs I think they were 5/8 threded plugs. One was enough but I put two just to be safe. Cant really remember it was a couple of years ago. Plus while you have the head off you could swap the hg and arp studs. :naughty: Cheap easy way is block off plates.
You can use this kind of block off plate on the back of the head vs tapping a plug fitting. It eliminates the EGR cooler.
The EGR will help reduce detonation and I experienced a 50-100 deg C drop in EGT. Both are due to the reasons posted above. The EGR has no effect on HP and keep in mind the stock (American version) ECU is tuned with an EGR installed.
The EGR will help reduce detonation and I experienced a 50-100 deg C drop in EGT. Both are due to the reasons posted above. The EGR has no effect on HP and keep in mind the stock (American version) ECU is tuned with an EGR installed.
jdub said:
thats a much better way to do the block off then taping the head
and since the egr was only flowing at low load conditions (idle and less than some percentage of throttle i dont know the number) i doubt there was much fuel or timing compensation for its use. especially since obd was not that advanced during the time and they would test for a closed egr valve. all im trying to say is i would not be worried about tearing the engine up because the stock tune compensated for a decrease in oxygen fraction
that being said the large amount of egt drop you noticed really suprises me considering the portion of egr flow is so small. where was your egt prob located
I agree...removing the EGR is not a huge issue ECU wise. Just wanted to make you guys aware of it.
The best thing to do would be to install a JDM ECU...it does not have the EGR function.
My EGT probe is located on the turbine housing, just before the mating flange to the manifold. It reads combined EGT for all the cylinders pre-turbo.
The big EGT drop actually surprised me as well, but it has been consistent.
The best thing to do would be to install a JDM ECU...it does not have the EGR function.
My EGT probe is located on the turbine housing, just before the mating flange to the manifold. It reads combined EGT for all the cylinders pre-turbo.
The big EGT drop actually surprised me as well, but it has been consistent.
My two cents:
1) EGR was originally developed to address detonation. The discovery that it reduces oxides of nitrogen was serendipitous.
2) Even in a healthy engine NOx production is near maximum in a stoichiometric mixture.
3) There's an entire section of the catalyst devoted solely to NOx reduction.
4) NOx is the primary cause of photochemically visible smog ie; that brown slop you see in the air. It's also the cause of acid rain.
In the 7M-GTE EGR does not operate any time the engine is cold, at idle, or above about 4000 rpm. When cold and above 4000 rpm it's killed by the ECU via the VSV. It's off at idle because the vacuum source is ported by the throttle plate.
While it's true EGR is off at WOT the mixture is much richer there. It's not rich under certain other loaded conditions. For example when climbing a grade below 4200 rpm while boosting under part throttle the 7M is still operating at stoichiometric with spark advanced to a high degree. Add to that a hot day and/or perhaps poor intercooling for whatever reason. These are conditions ripe for detonation. Consider this statement taken from the TCCS manual:
" EGR is necessary during cruising and midrange acceleration when combustion temperatures are typically very high".
As far as ECU programing for EGR goes the manual further states:
"The ECU considers the EGR system as an integral part of the entire engine control system. It is capable of neutralizing negative performance aspects of EGR by programing additional spark advance and decreased fuel injection during periods of EGR flow. By integrating spark and fuel control with the EGR engine performance is actually enhanced when the EGR system is functioning."
If that's not clear enough I'll make it clearer: The ECU advances spark and reduces injection duration when it "thinks" EGR is flowing and has no way of knowing you've defeated it. Keeping all of the above in mind the manuals further state (in various places):
"Too little EGR may cause detonation." "Loss of EGR typically causes detonation to occur." "If EGR is commanded and doesn't flow severe detonation will result."
While it's true the knock control system will address this it only happens after the detonation has begun. Unlike many here I'm convinced a fair number of failures on these engines are the result of defeating EGR combined with other mistakes ie; not increasing octane, poorly done rebuilds/modifications, and/or incorrect tuning. My advice is if you take it off you'd better use other than a stock HG, make sure the engine is running perfectly at other than WOT, and start paying more at the pump.
I won't comment on the environmental aspect other than to say I find it amusing most youngsters, who'll have to live with it the longest, are usually the ones quickest to shit in it...
1) EGR was originally developed to address detonation. The discovery that it reduces oxides of nitrogen was serendipitous.
2) Even in a healthy engine NOx production is near maximum in a stoichiometric mixture.
3) There's an entire section of the catalyst devoted solely to NOx reduction.
4) NOx is the primary cause of photochemically visible smog ie; that brown slop you see in the air. It's also the cause of acid rain.
In the 7M-GTE EGR does not operate any time the engine is cold, at idle, or above about 4000 rpm. When cold and above 4000 rpm it's killed by the ECU via the VSV. It's off at idle because the vacuum source is ported by the throttle plate.
While it's true EGR is off at WOT the mixture is much richer there. It's not rich under certain other loaded conditions. For example when climbing a grade below 4200 rpm while boosting under part throttle the 7M is still operating at stoichiometric with spark advanced to a high degree. Add to that a hot day and/or perhaps poor intercooling for whatever reason. These are conditions ripe for detonation. Consider this statement taken from the TCCS manual:
" EGR is necessary during cruising and midrange acceleration when combustion temperatures are typically very high".
As far as ECU programing for EGR goes the manual further states:
"The ECU considers the EGR system as an integral part of the entire engine control system. It is capable of neutralizing negative performance aspects of EGR by programing additional spark advance and decreased fuel injection during periods of EGR flow. By integrating spark and fuel control with the EGR engine performance is actually enhanced when the EGR system is functioning."
If that's not clear enough I'll make it clearer: The ECU advances spark and reduces injection duration when it "thinks" EGR is flowing and has no way of knowing you've defeated it. Keeping all of the above in mind the manuals further state (in various places):
"Too little EGR may cause detonation." "Loss of EGR typically causes detonation to occur." "If EGR is commanded and doesn't flow severe detonation will result."
While it's true the knock control system will address this it only happens after the detonation has begun. Unlike many here I'm convinced a fair number of failures on these engines are the result of defeating EGR combined with other mistakes ie; not increasing octane, poorly done rebuilds/modifications, and/or incorrect tuning. My advice is if you take it off you'd better use other than a stock HG, make sure the engine is running perfectly at other than WOT, and start paying more at the pump.
I won't comment on the environmental aspect other than to say I find it amusing most youngsters, who'll have to live with it the longest, are usually the ones quickest to shit in it...
:bowdown:
Thanks for the breakdown jet.
And since I'm a hippy at heart, I totally agree, keep the EGR!!!! Hug a tree!!!
Thanks for the breakdown jet.
And since I'm a hippy at heart, I totally agree, keep the EGR!!!! Hug a tree!!!
i made a huge post and just deleted all of it because i want to discuss one point
where did you find that egr was created to reduce pre ignition
egr ,while reducing peak flame temperature there by reducing the chance of the flame front jumping in the cylinder, actually causes slower combustion
the slower combustion actually causes the combustion waves to be more unstable especially at no load conditions the reason for the timing advance is to offset the longer combustion times and the reason to decrease fuel is the egr carries in hydrocarbons
i want to put a disclaimer here i am totally agreeing that removing the egr will increase engine out NOX emmissions
i also agree that there are look up tables in the ecu to correct timing and fueling for egr flow (i still havent been told if the valve is a steper or just a on off)
i agree there will be changes in the combustion process if you remove the egr valve
i am debateing the origins of egr and the magnitude of the antiknock effects
one more disclaimer this is a discussion not a arguement im not trying to show anyone any disrespect merely exchanging ideas that may result in further research into the depths of the 7m ecu
perhaps i will borrow a scope and watch injection timing
where did you find that egr was created to reduce pre ignition
egr ,while reducing peak flame temperature there by reducing the chance of the flame front jumping in the cylinder, actually causes slower combustion
the slower combustion actually causes the combustion waves to be more unstable especially at no load conditions the reason for the timing advance is to offset the longer combustion times and the reason to decrease fuel is the egr carries in hydrocarbons
i want to put a disclaimer here i am totally agreeing that removing the egr will increase engine out NOX emmissions
i also agree that there are look up tables in the ecu to correct timing and fueling for egr flow (i still havent been told if the valve is a steper or just a on off)
i agree there will be changes in the combustion process if you remove the egr valve
i am debateing the origins of egr and the magnitude of the antiknock effects
one more disclaimer this is a discussion not a arguement im not trying to show anyone any disrespect merely exchanging ideas that may result in further research into the depths of the 7m ecu
perhaps i will borrow a scope and watch injection timing
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JJ...agree 100 %.
Had a custom FFIM made:
That piping leading to behind the TB flange is for the EGR
The effect the ECU has in conjunction with the EGR was a bit more than I thought
Nice write-up.
Had a custom FFIM made:
That piping leading to behind the TB flange is for the EGR
The effect the ECU has in conjunction with the EGR was a bit more than I thought
Nice write-up.
EGR was originally investigated for reducing detonation, which it does well. Search around and you'll find the references. If the engine is working right EGR flow carries minimal HC. The valve is a simple normally closed diaphragm type that's modulated by manifold and exhaust pressure. Finally, preigniton is a completely different phenomena than detonation. Seems to me a Supraguru should already know that stuff
I'm not saying running sans EGR will blow all engines up. Guys with the experience and knowledge of Adjuster have little to worry about and in fact they don't suffer the problems others do. It's almost unheard of to see someone like him, IJ, Jdub, and some others here with problems. That expertise isn't applicable to everyone.
What's left is people who yank stuff they don't understand off engines that aren't likely running right to begin with, don't rebuild properly, can't afford to do it right, modify without knowing how things work, ect. Lets face it, there are many owners who shouldn't even be near the car with tools and I'm talking about stock repairs. Forget about modifications. These people are messing with things at their own risk. My sig pretty much sums it up.
Add to that the age and condition of these cars. I have yet to work on a MKIII that I didn't find something wrong with even though the owner swore it was running perfect. It's because most people don't invest in the knowledge and test gear to really know what their engines are doing.
Some the information in the factory training manuals is reproduced on the Autoshop 101 website. For those interested I suggest reading the EGR section (number 61) in the Tech Articles. In fact if owners would study that entire site they'd become much better informed:
http://tinyurl.com/4ta5g
You can look at the EGR system as kind of like fuel cut in that it provides protection against those who don't understand how sophisticated the TCCS is. If you're one of them be careful what you mess with. Course, I'm just relaying how this stuff works. There's no law that says anyone has to believe me. In the end it's your car to do as you wish with.
As far as ECU depth you're talking to a guy who has a factory TCCS checker/simulator plus another built from scratch. I can and have run the computer under just about any condition you can think off. In fact I quit doing that a long time ago. Plus I've run the car instrumented to the teeth (portable ignition scope, 5 gas analysis, ect) in just about every configuration imaginable. I know stuff about the box that I've never seen mentioned anywhere. Stuff people would kill for. Keeping some of it to myself is one of the pleasures I get from being here
I'm not saying running sans EGR will blow all engines up. Guys with the experience and knowledge of Adjuster have little to worry about and in fact they don't suffer the problems others do. It's almost unheard of to see someone like him, IJ, Jdub, and some others here with problems. That expertise isn't applicable to everyone.
What's left is people who yank stuff they don't understand off engines that aren't likely running right to begin with, don't rebuild properly, can't afford to do it right, modify without knowing how things work, ect. Lets face it, there are many owners who shouldn't even be near the car with tools and I'm talking about stock repairs. Forget about modifications. These people are messing with things at their own risk. My sig pretty much sums it up.
Add to that the age and condition of these cars. I have yet to work on a MKIII that I didn't find something wrong with even though the owner swore it was running perfect. It's because most people don't invest in the knowledge and test gear to really know what their engines are doing.
Some the information in the factory training manuals is reproduced on the Autoshop 101 website. For those interested I suggest reading the EGR section (number 61) in the Tech Articles. In fact if owners would study that entire site they'd become much better informed:
http://tinyurl.com/4ta5g
You can look at the EGR system as kind of like fuel cut in that it provides protection against those who don't understand how sophisticated the TCCS is. If you're one of them be careful what you mess with. Course, I'm just relaying how this stuff works. There's no law that says anyone has to believe me. In the end it's your car to do as you wish with.
As far as ECU depth you're talking to a guy who has a factory TCCS checker/simulator plus another built from scratch. I can and have run the computer under just about any condition you can think off. In fact I quit doing that a long time ago. Plus I've run the car instrumented to the teeth (portable ignition scope, 5 gas analysis, ect) in just about every configuration imaginable. I know stuff about the box that I've never seen mentioned anywhere. Stuff people would kill for. Keeping some of it to myself is one of the pleasures I get from being here
jetjock said:Finally, preigniton is a completely different phenomena than detonation. Seems to me a Supraguru should already know that stuff
QUOTE]
well i interchange the words when im not talking to engineers who use the terms correctly.
for reference for anyone spying in
knock currently has two theories to explain its orgin
autoignition and detonation
ill focus on detonation since that is what is being discussed
detonation is the theory that under knocking conditions the flame front accelerates to sonic velocity and takes over the unburned gas mixure at a rate much faster than it would under normal conditions. this is a attempt to explain the knock phenomina which is rapid release of energy in the unburned region of the clyinder. this theory also would explain the second part of knock which is the transmission of strong perssure waves accross the cylinder and the sound that resonates through the engine.
currently at least downstairs in the advanced combustion group the auto ignition theory is winning as the main cause of end gas energy release.
okay so we will settlethis as so
we both aggree that egr obviously slows the flame front down thereby keeping the end gas cooler reducing NOx and reduceing the chances of autoignition of the end gas. the best research ive been able to do shows GM being the first with egr in the 70s and it was used to reduce NOx.
i end with this picture out of a book which is pretty much a combustion engineers bible
it shows two graphs one showing the spark advance needed to achieve maximum brake torque
the one below showing bsfc for a moderate speed and high speed combustion chamber as you can see the only reason spark advance increases is because the reaction is becoming more inefficent with egr and hapening slower and at the expense of power. you can also see for this range of combustion speeds the timing adjustment for flowing egr for the moderate speed is 5 degrees and for the fast combustion chamber (not us) 10 degrees
since you have access to a scope and i am using the one at work right now maybe you can watch timing to see how much the stock ecu adjusts for egr on points
i still feel that egr only buys you more knock margin because it takes away from engine performance. if you put egr on a engine in order to get it back to the performance level it was at you HAVE to advance timing and pull fuel
o and i understand how complicated the ecu is. i work tuneing the calibration for engines at work and half of our day is spent negotiating with the software people versus processing data from the test cells. if people knew just how many tables and parameters there were in ecms i think they would be blown away
A couple of points to consider SG:
The EGR does produce a performance hit...that is why it is disabled above 4000 rpm, the engineers limited the hit to lower power ranges. All you have to do is add a bit more throttle and you got the power you need at the mid rpm range. The real issue here is not the performance hit due to the EGR, but what the ECU does when it's removed...keep in mind the stock ECU timing/fuel tables are CAN NOT be user modified.
The ECU does advance timing and pull fuel at the mid rpm range...the effect of this without the EGR can very well produce detonation (or autoignition, if that's what you want to call it). That makes removing the EGR without using a standalone, JDM ECU, or some method to control fuel/timing a bad thing.
The EGR does produce a performance hit...that is why it is disabled above 4000 rpm, the engineers limited the hit to lower power ranges. All you have to do is add a bit more throttle and you got the power you need at the mid rpm range. The real issue here is not the performance hit due to the EGR, but what the ECU does when it's removed...keep in mind the stock ECU timing/fuel tables are CAN NOT be user modified.
The ECU does advance timing and pull fuel at the mid rpm range...the effect of this without the EGR can very well produce detonation (or autoignition, if that's what you want to call it). That makes removing the EGR without using a standalone, JDM ECU, or some method to control fuel/timing a bad thing.