EGR Block-Off
03-06-2003, 01:18 AM
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EGR Block-Off I have an EGR block-off plate that I put in and am wondering if this has any adverse affects. Some people I talk to say the EGR doesnt do anything. Others say it plays a vital role in engine operation. What does it do? And if deleted what could happen?
03-06-2003, 07:02 PM
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Re: EGR Block-Off </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by silverado:
<strong> I have an EGR block-off plate that I put in and am wondering if this has any adverse affects. Some people I talk to say the EGR doesnt do anything. Others say it plays a vital role in engine operation. What does it do? And if deleted what could happen? </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">What does it do?
The EGR in a nutshell is there to reduce emmissions by circulating exhaust gas back into your intake.
If deleted what could happen?
The EGR allows timing to be advanced much higher than normal because it slows and cools the combustion process (less oxygen in the exhaust gas). Deleting the EGR on a car with the stock cam is risky business. The timing table may end up being too aggressive for an engine without an EGR.
If you longer have the stock cam, then I would ****-can the EGR. Almost all (unless you purchased a complete wussy cam) aftermarket cams will have enough overlap and exhaust reversion (this is the part of the cam that makes the EGR not needed) to make the EGR unecessary.
Benefits of ****-Canning the EGR?
If you have ever looked at your intake, the EGR occupies a substantial amount of space. Eliminated the EGR make the intake tract less restrictive. Will you gain 20 HP..... probably not. Will you gain 2 HP..... probably.
<strong> I have an EGR block-off plate that I put in and am wondering if this has any adverse affects. Some people I talk to say the EGR doesnt do anything. Others say it plays a vital role in engine operation. What does it do? And if deleted what could happen? </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">What does it do?
The EGR in a nutshell is there to reduce emmissions by circulating exhaust gas back into your intake.
If deleted what could happen?
The EGR allows timing to be advanced much higher than normal because it slows and cools the combustion process (less oxygen in the exhaust gas). Deleting the EGR on a car with the stock cam is risky business. The timing table may end up being too aggressive for an engine without an EGR.
If you longer have the stock cam, then I would ****-can the EGR. Almost all (unless you purchased a complete wussy cam) aftermarket cams will have enough overlap and exhaust reversion (this is the part of the cam that makes the EGR not needed) to make the EGR unecessary.
Benefits of ****-Canning the EGR?
If you have ever looked at your intake, the EGR occupies a substantial amount of space. Eliminated the EGR make the intake tract less restrictive. Will you gain 20 HP..... probably not. Will you gain 2 HP..... probably.
03-07-2003, 12:11 AM
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Re: EGR Block-Off That's because the newer LS1's also have a slightly different cam profile (the ramps I believe) that take this into account therefore eliminating the need for an EGR system.
I've been arguing this with people that remove their EGR system on EGR equipped cars. Why? At WOT the PCM overrides it and turns off the EGR anyway, so even when it's there at WOT it has no effect anyway. The EGR is to help part throttle and low speed driveability.
Here is what I took directly off GM's SI2000 system (Service Information 2000). This is what GM writes! Not me.
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Exhaust Gas Recirculation (EGR) System Description
EGR Valve
Purpose
An Exhaust Gas Recirculation (EGR) system is used in order to lower Oxides of Nitrogen (NOx) emission levels. The EGR system accomplishes this by feeding small amounts of exhaust gas back into the combustion chamber. High combustion temperatures cause NOx. Combustion temperatures are reduced when the air/fuel mixture is diluted with the exhaust gases.
Operation
(1) Cap-Sensor
(2) Sensor-EGR Pintle Position
(3) Pole Piece-Primary
(4) Bobbin and Coil Assembly
(5) Sleeve-Armature
(6) Valve-Pintle
(7) Armature and Base Assembly
The EGR valve is designed to accurately supply exhaust gases to the engine without the use of intake manifold vacuum. The EGR valve controls the exhaust flow into the intake manifold from the exhaust manifold through an orifice with a PCM controlled pintle. The PCM controls the pintle position using inputs from the Engine Coolant Temperature (ECT) sensor, the Throttle Position (TP) sensor, and the Manifold Absolute Pressure (MAP) sensor. The PCM commands the EGR valve in order to supply the correct amount of exhaust gas recirculation for the current engine operating conditions. This can be monitored on a scan tool as the Desired EGR Position.
The PCM monitors the position of the EGR valve through a feedback signal. The PCM supplies a 5.0 volt reference and a ground to the EGR valve. A voltage signal representing the EGR valve pintle position is sent to the PCM from the EGR valve. This feedback signal can also be monitored on a scan tool and is the actual position of the EGR pintle. The Actual EGR Position should always be near the commanded or Desired EGR Position.
The EGR valve is usually activated under the following conditions:
-The engine is warm.
-The engine is above the idle speed.
Diagnosis
(1) Linear EGR Valve
(2) Exhaust Gas
(3) To Cylinders
(4) Pintle
Too much EGR flow causes any of the following conditions to occur:
The engine stalls after a cold start.
The engine stalls during closed throttle conditions.
The vehicle surges during a cruise condition.
A rough idle.
A DTC P0300 (misfire detected).
Too little or no EGR flow allows the combustion temperatures to increase. This causes the following symptoms:
Spark knock (detonation)
Engine overheating
Emission test failure
DTC P0401
Poor fuel economy
The EGR flow diagnosis is included in the DTC P0401 diagnostic table. The EGR pintle position and the EGR valve control circuit diagnosis are covered in DTCs P0404, P0405, and P1404. Go to the appropriate DTC table for diagnosis if an EGR diagnostic trouble code is stored.</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">With that said, in normal everyday driving (non WOT driving) on EGR equipped vehicles it is actually HELPING you by making the engine run smoother, eliminate spark knock, and help overall engine responsiveness. If you run it WOT, the PCM detects the TP signal and overrides the EGR system "off" and therefore isn't a factor in any performance or hurting performance any.
About the only gain one can get out of eliminating EGR for drag purposes is weight savings. The whole 10-15 pounds at most that the entire plumbing and pump weigh doesn't amount to a whole hill of beans and is counterproductive when the driveability suffers some.
Someone argued that it injected dirty (carbonized exhaust) back into the intake stream and a better method is to eliminate the EGR and plumb N20 in to help. It'll also keep the inside of your intake clean. I countered..."when was the last time you ate off the inside of your intake plenum?" Who cares! I know we knock some of GM's engineer's thinking on things, but they have obviously thought this matter out, otherwise we'd all have little nitrous bottles feeding into our intakes in place of an EGR system.
With that said, when I installed my LS6 intake, I went through all the steps and great pains to plumb in my EGR system. The car runs like a dream with it.
Prior to putting on my LS6 intake, Ed Wrong turned off the EGR on my PCM and I suffered 12-16 degrees of knock retard at throttle tip in and light throttle applications cause the engine was pinging and plucking left and right. The car ran like sh*t and in order to simply get the car moving from a dead stop, I had to rev it to 3k, as I mixed in the clutch. After I found out it was turned off (by monitoring the pintle position) I turned it back on with a Tech2 and all knock retard, all hesitation, were gone and afterwords, I can simply let the clutch out and the car will roll without knock, hesitation, chugging, etc, etc. Nice and smooth.
Sorry, I see no need to eliminate it. It helps for normal driving and isn't even involved under WOT.
I've been arguing this with people that remove their EGR system on EGR equipped cars. Why? At WOT the PCM overrides it and turns off the EGR anyway, so even when it's there at WOT it has no effect anyway. The EGR is to help part throttle and low speed driveability.
Here is what I took directly off GM's SI2000 system (Service Information 2000). This is what GM writes! Not me.
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Exhaust Gas Recirculation (EGR) System Description
EGR Valve
Purpose
An Exhaust Gas Recirculation (EGR) system is used in order to lower Oxides of Nitrogen (NOx) emission levels. The EGR system accomplishes this by feeding small amounts of exhaust gas back into the combustion chamber. High combustion temperatures cause NOx. Combustion temperatures are reduced when the air/fuel mixture is diluted with the exhaust gases.
Operation
(1) Cap-Sensor
(2) Sensor-EGR Pintle Position
(3) Pole Piece-Primary
(4) Bobbin and Coil Assembly
(5) Sleeve-Armature
(6) Valve-Pintle
(7) Armature and Base Assembly
The EGR valve is designed to accurately supply exhaust gases to the engine without the use of intake manifold vacuum. The EGR valve controls the exhaust flow into the intake manifold from the exhaust manifold through an orifice with a PCM controlled pintle. The PCM controls the pintle position using inputs from the Engine Coolant Temperature (ECT) sensor, the Throttle Position (TP) sensor, and the Manifold Absolute Pressure (MAP) sensor. The PCM commands the EGR valve in order to supply the correct amount of exhaust gas recirculation for the current engine operating conditions. This can be monitored on a scan tool as the Desired EGR Position.
The PCM monitors the position of the EGR valve through a feedback signal. The PCM supplies a 5.0 volt reference and a ground to the EGR valve. A voltage signal representing the EGR valve pintle position is sent to the PCM from the EGR valve. This feedback signal can also be monitored on a scan tool and is the actual position of the EGR pintle. The Actual EGR Position should always be near the commanded or Desired EGR Position.
The EGR valve is usually activated under the following conditions:
-The engine is warm.
-The engine is above the idle speed.
Diagnosis
(1) Linear EGR Valve
(2) Exhaust Gas
(3) To Cylinders
(4) Pintle
Too much EGR flow causes any of the following conditions to occur:
The engine stalls after a cold start.
The engine stalls during closed throttle conditions.
The vehicle surges during a cruise condition.
A rough idle.
A DTC P0300 (misfire detected).
Too little or no EGR flow allows the combustion temperatures to increase. This causes the following symptoms:
Spark knock (detonation)
Engine overheating
Emission test failure
DTC P0401
Poor fuel economy
The EGR flow diagnosis is included in the DTC P0401 diagnostic table. The EGR pintle position and the EGR valve control circuit diagnosis are covered in DTCs P0404, P0405, and P1404. Go to the appropriate DTC table for diagnosis if an EGR diagnostic trouble code is stored.</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">With that said, in normal everyday driving (non WOT driving) on EGR equipped vehicles it is actually HELPING you by making the engine run smoother, eliminate spark knock, and help overall engine responsiveness. If you run it WOT, the PCM detects the TP signal and overrides the EGR system "off" and therefore isn't a factor in any performance or hurting performance any.
About the only gain one can get out of eliminating EGR for drag purposes is weight savings. The whole 10-15 pounds at most that the entire plumbing and pump weigh doesn't amount to a whole hill of beans and is counterproductive when the driveability suffers some.
Someone argued that it injected dirty (carbonized exhaust) back into the intake stream and a better method is to eliminate the EGR and plumb N20 in to help. It'll also keep the inside of your intake clean. I countered..."when was the last time you ate off the inside of your intake plenum?" Who cares! I know we knock some of GM's engineer's thinking on things, but they have obviously thought this matter out, otherwise we'd all have little nitrous bottles feeding into our intakes in place of an EGR system.
With that said, when I installed my LS6 intake, I went through all the steps and great pains to plumb in my EGR system. The car runs like a dream with it.
Prior to putting on my LS6 intake, Ed Wrong turned off the EGR on my PCM and I suffered 12-16 degrees of knock retard at throttle tip in and light throttle applications cause the engine was pinging and plucking left and right. The car ran like sh*t and in order to simply get the car moving from a dead stop, I had to rev it to 3k, as I mixed in the clutch. After I found out it was turned off (by monitoring the pintle position) I turned it back on with a Tech2 and all knock retard, all hesitation, were gone and afterwords, I can simply let the clutch out and the car will roll without knock, hesitation, chugging, etc, etc. Nice and smooth.
Sorry, I see no need to eliminate it. It helps for normal driving and isn't even involved under WOT.
03-07-2003, 12:45 AM
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Re: EGR Block-Off Thank you for the well informed responses! I do have an aftermarket cam (LT4 Hot Cam) Do any of you think that the cam is providing enough "egr" by itself through overlap etc.? I am having an issue with knock retard. I get a permanent 4.84 volts from my knock sensor, so I am trouble shooting that right now (no responses on that thread yet) I will take off the block off and see if that changes my knock readings at all. Any other suggestions. I do have auto-tap but am not very proficient at this time, so any words of wisdom are greatly appreciated.
03-07-2003, 12:50 AM
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Re: EGR Block-Off Another benefit to removing the EGR can be seen just by looking inside the tubes. They're full of black deposits. Just like the inside of your exhaust pipes.
03-08-2003, 12:33 AM
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Re: EGR Block-Off </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by NoGo:
<strong> Benefits of ****-Canning the EGR?
If you have ever looked at your intake, the EGR occupies a substantial amount of space. Eliminated the EGR make the intake tract less restrictive. Will you gain 20 HP..... probably not. Will you gain 2 HP..... probably. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">If you check out the free mods section of LS1.com this was one of the first "free mods" I did. It involves cutting the pipe/tube that is in the path of the airflow's way.
The EGR system still works, still injects, and still mixes with fresh incoming air. However, it no longer restricts free air-flow.
What we are referring to is people completely eliminating their EGR system by either turning off the system in the PCM and then removing all equipment for weight savings or simply blocking it off as Silverado has done with the block off plate.
If you insist on eliminating it, hey it's your vehicle, do what you want. However, I refuse to sacrafice everyday drivability when in return it provides me NO performance benefit because as I said, at WOT it's turned off anyway.
<strong> Benefits of ****-Canning the EGR?
If you have ever looked at your intake, the EGR occupies a substantial amount of space. Eliminated the EGR make the intake tract less restrictive. Will you gain 20 HP..... probably not. Will you gain 2 HP..... probably. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">If you check out the free mods section of LS1.com this was one of the first "free mods" I did. It involves cutting the pipe/tube that is in the path of the airflow's way.
The EGR system still works, still injects, and still mixes with fresh incoming air. However, it no longer restricts free air-flow.
What we are referring to is people completely eliminating their EGR system by either turning off the system in the PCM and then removing all equipment for weight savings or simply blocking it off as Silverado has done with the block off plate.
If you insist on eliminating it, hey it's your vehicle, do what you want. However, I refuse to sacrafice everyday drivability when in return it provides me NO performance benefit because as I said, at WOT it's turned off anyway.
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03-08-2003, 12:38 AM
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Re: EGR Block-Off </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by 2000WhiteZ28:
<strong> Another benefit to removing the EGR can be seen just by looking inside the tubes. They're full of black deposits. Just like the inside of your exhaust pipes. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Go read my first reply to this thread. You'll see I've had this argued with me before.
Have you checked the tops of your pistons and the combustion chamber in general? In case you haven't, they're covered in carbon and the aftermath of combustion. So do you not run your engine for fear of getting the tops of your pistons and combustion chamber dirty?
Black deposits on the inside of your intake plenum don't hurt a damn thing. That is unless you eat your dinner off of it!
<strong> Another benefit to removing the EGR can be seen just by looking inside the tubes. They're full of black deposits. Just like the inside of your exhaust pipes. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Go read my first reply to this thread. You'll see I've had this argued with me before.
Have you checked the tops of your pistons and the combustion chamber in general? In case you haven't, they're covered in carbon and the aftermath of combustion. So do you not run your engine for fear of getting the tops of your pistons and combustion chamber dirty?
Black deposits on the inside of your intake plenum don't hurt a damn thing. That is unless you eat your dinner off of it!
03-08-2003, 12:46 AM
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Re: EGR Block-Off I have a 99 trans am with the following mods done k&n FIPK 2, Mac headers w/off road y-pipe, hooker cat-back exhaust, LS6 intake W/NO EGR! b&m ripper, 160 thermostat, rear O2 simms, and only enough LS1 edit to do the hypertech tuning and delete some engine codes, and have removed the smog pump and egr. And I have no problems what so ever w/driveability. Data logged w/autotap last nite and everything is fine. Working like a champ!! So maybe some peoples cars are a little moody and don't like some changes. And others do. So there's no harm in blocking it off and seeing what happens. If you lose everyday driveability, then unblock it and connect everything back up takes maybe 15 minutes at most. And if not, remove the rest of the pump and your in business!!!
05-16-2003, 08:50 AM
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Re: EGR Block-Off
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by silverado:
<strong> I have an EGR block-off plate that I put in and am wondering if this has any adverse affects. Some people I talk to say the EGR doesnt do anything. Others say it plays a vital role in engine operation. What does it do? And if deleted what could happen? </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">What does it do?
The EGR in a nutshell is there to reduce emmissions by circulating exhaust gas back into your intake.
If deleted what could happen?
The EGR allows timing to be advanced much higher than normal because it slows and cools the combustion process (less oxygen in the exhaust gas). Deleting the EGR on a car with the stock cam is risky business. The timing table may end up being too aggressive for an engine without an EGR.
If you longer have the stock cam, then I would ****-can the EGR. Almost all (unless you purchased a complete wussy cam) aftermarket cams will have enough overlap and exhaust reversion (this is the part of the cam that makes the EGR not needed) to make the EGR unecessary.
Benefits of ****-Canning the EGR?
If you have ever looked at your intake, the EGR occupies a substantial amount of space. Eliminated the EGR make the intake tract less restrictive. Will you gain 20 HP..... probably not. Will you gain 2 HP..... probably.
<strong> I have an EGR block-off plate that I put in and am wondering if this has any adverse affects. Some people I talk to say the EGR doesnt do anything. Others say it plays a vital role in engine operation. What does it do? And if deleted what could happen? </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">What does it do?
The EGR in a nutshell is there to reduce emmissions by circulating exhaust gas back into your intake.
If deleted what could happen?
The EGR allows timing to be advanced much higher than normal because it slows and cools the combustion process (less oxygen in the exhaust gas). Deleting the EGR on a car with the stock cam is risky business. The timing table may end up being too aggressive for an engine without an EGR.
If you longer have the stock cam, then I would ****-can the EGR. Almost all (unless you purchased a complete wussy cam) aftermarket cams will have enough overlap and exhaust reversion (this is the part of the cam that makes the EGR not needed) to make the EGR unecessary.
Benefits of ****-Canning the EGR?
If you have ever looked at your intake, the EGR occupies a substantial amount of space. Eliminated the EGR make the intake tract less restrictive. Will you gain 20 HP..... probably not. Will you gain 2 HP..... probably.
Well my timing hasn't dropped a bit since I removed mine. You are correct about the temp though. Thats the whole point of it. I can't remember the exact temp at which the nitrogen combines with oxygen to form NOx but the EGR keeps it below this threshold.
