EGR - Engine operation.

[Bigsyke]

Question isnt about how to remove the EGR stuff, but more about the conflicting things I hear about directly affecting engine operation.

Looking through teh FSM, the EGR didnt DIRECTLY control engine operation, but im sure it affects it somehow. If someone removes the EGR stuff, ive heard the engine runs warmer, run's richer? and pings (preignition - or detonation?)

Some have said no tuning programs can offset the EGR equipment, but how come I see everybody ripping the EGR stuff out, and not having any problems?

On the honda civics (5th gen) they had an EGR, and everybody removed it because it didnt affect engine operation, honda removed the EGR on the 6th gen due to issues.

So with an EGR system removed, there are no ways to achieve normal engine operation? russ??

[projectRDM]

I have been removing EGR systems for years on KAs. There's plenty of benefits, and a few drawbacks.

You are right, the engine temperature can increase without the EGR valve, the system does let cooler air into the exhaust during certain conditions to cool it, therefore cooling the entire engine. It's a limited time though, and with proper cooling, throttle coolant bypass, and items like a cooling panel or phelonic intake gasket you'll never notice it.

The main advantage is simply a cleaner intake manifold and one that mixes the correct air/fuel ratio. Anyone who's ever removed a KA intake manifold knows how nasty it is inside, soot and carbon buildup from the EGR and carbon canister. If you've ever been able to remove the M10 allen plugs in the EGR passage you've seen the shit inside, it's nasty as hell. Every time I have a plenum hot tanked I'm amazed at the shit that comes out of it. On one I left the EGR valve on just to see the difference, once cleaned I removed the valve and was greeted to several ounces off sludge dripping out. The soot remains sticky, making it susceptible to more contamination of grit and dirt. Once cleaned and bypassed I've removed intakes over a year later and they were still shiny and smooth inside. All that excess soot does find it's way into the cylinders, and adds to the exhaust charge by being burned within. Plus some of it leads out the PCV and crankcase vent, all of which is sucked right back in and reburned. It's like taking a shit only to eat it and shit it out again. Sure it's broken down the second time through, but it's still shit.

Secondly, when the EGR is pulling from the exhaust you're receiving CO2 into the intake. While there really isn't any oxygen left in it there's still added volume, and since it's past the MAF you're basically introducing more 'air' in the engine to which the ECU must adjust to, even though there's nothing to really burn. This throws off the A/Fs a little since the measure of fuel injected is to compensate for the metered air at the MAF, which is measured in mass. However that actual mass is increased when the EGR passage opens, but it's after the measurement so the fuel isn't properly calibrated.

Ideally you'll never notice a difference one way or the other besides a cleaner engine, a cleaner engine bay, and ease of working on the engine as a whole. On some cars the EGR system failing does nothing (like our cars) but on some cars like the Mitsubishi 2.7L V6, the EGR system works backwards and when failed it remains open, flooding the intake with exhaust gas and atomizing the fuel before it even ignites, resulting in severe overheating and lean conditions.

The overall purpose is simply to reduce emissions, but think about it like this, if the air you're burning is already cleaner by not having to break down the CO2 from the exhaust, wouldn't the outcome be the same?

[g6civcx]

how come I see everybody ripping the EGR stuff out, and not having any problems?


Another issue to consider is that it's illegal to remove any part of the emissions sytem. The EGR is a part of the emissions, so if you want your car to be street legal, your EGR must be present and functional.

[Bigsyke]

Another issue to consider is that it's illegal to remove any part of the emissions sytem. The EGR is a part of the emissions, so if you want your car to be street legal, your EGR must be present and functional.


No emissions in my state yet.

I am removing my IM to change the PCV valve and gaskets. My EGR system is corroded, and the hoses are freyed.

Russ that was the best info I have receieved, ever! I would posi rep, but yea...

[SexPanda]

Another issue to consider is that it's illegal to remove any part of the emissions sytem. The EGR is a part of the emissions, so if you want your car to be street legal, your EGR must be present and functional.

Thats only a problem if you live in a state thats big on emissions, and you dont have an inspectors liscense. lol

Basically, move to MO if you dont want to deal with that.

[Om1kron]

Another issue to consider is that it's illegal to remove any part of the emissions sytem. The EGR is a part of the emissions, so if you want your car to be street legal, your EGR must be present and functional.

That's a bit drastic... The car will not pass a visual smog inspection, but will most likely pass all other smog tests.

[Om1kron]

I have been removing EGR systems for years on KAs. There's plenty of benefits, and a few drawbacks.

You are right, the engine temperature can increase without the EGR valve, the system does let cooler air into the exhaust during certain conditions to cool it, therefore cooling the entire engine. It's a limited time though, and with proper cooling, throttle coolant bypass, and items like a cooling panel or phelonic intake gasket you'll never notice it.

The main advantage is simply a cleaner intake manifold and one that mixes the correct air/fuel ratio. Anyone who's ever removed a KA intake manifold knows how nasty it is inside, soot and carbon buildup from the EGR and carbon canister. If you've ever been able to remove the M10 allen plugs in the EGR passage you've seen the shit inside, it's nasty as hell. Every time I have a plenum hot tanked I'm amazed at the shit that comes out of it. On one I left the EGR valve on just to see the difference, once cleaned I removed the valve and was greeted to several ounces off sludge dripping out. The soot remains sticky, making it susceptible to more contamination of grit and dirt. Once cleaned and bypassed I've removed intakes over a year later and they were still shiny and smooth inside. All that excess soot does find it's way into the cylinders, and adds to the exhaust charge by being burned within. Plus some of it leads out the PCV and crankcase vent, all of which is sucked right back in and reburned. It's like taking a shit only to eat it and shit it out again. Sure it's broken down the second time through, but it's still shit.

Secondly, when the EGR is pulling from the exhaust you're receiving CO2 into the intake. While there really isn't any oxygen left in it there's still added volume, and since it's past the MAF you're basically introducing more 'air' in the engine to which the ECU must adjust to, even though there's nothing to really burn. This throws off the A/Fs a little since the measure of fuel injected is to compensate for the metered air at the MAF, which is measured in mass. However that actual mass is increased when the EGR passage opens, but it's after the measurement so the fuel isn't properly calibrated.

Ideally you'll never notice a difference one way or the other besides a cleaner engine, a cleaner engine bay, and ease of working on the engine as a whole. On some cars the EGR system failing does nothing (like our cars) but on some cars like the Mitsubishi 2.7L V6, the EGR system works backwards and when failed it remains open, flooding the intake with exhaust gas and atomizing the fuel before it even ignites, resulting in severe overheating and lean conditions.

The overall purpose is simply to reduce emissions, but think about it like this, if the air you're burning is already cleaner by not having to break down the CO2 from the exhaust, wouldn't the outcome be the same?


I missed the drawbacks here.

[Mister.E]

man that was one hell of a good breakdown. +rep for you!

[blackej7]

Secondly, when the EGR is pulling from the exhaust you're receiving CO2 into the intake. While there really isn't any oxygen left in it there's still added volume, and since it's past the MAF you're basically introducing more 'air' in the engine to which the ECU must adjust to, even though there's nothing to really burn. This throws off the A/Fs a little since the measure of fuel injected is to compensate for the metered air at the MAF, which is measured in mass. However that actual mass is increased when the EGR passage opens, but it's after the measurement so the fuel isn't properly calibrated.


Someone correct me if I'm wrong here:

When EGR is commanded (which is typically on the highway, low load/higher rpm), your introducing an already combusted (can not be burned) mixture back into the engine, which displaces air. With less air in the mixture, the o2 sensor will pick up on a rich A/F ratio, and pull the fuel trims back, giving you better gas mileage and cooler combustion. I don't see an advantage to removing EGR unless its a track car. You won't notice a difference because when EGR is commanded, your at cruising speed under very little load.

I'm not exactly sure what Nissan's specific strategy is for EGR operation, so I don't know how removing it will affect drivability.

[Bigsyke]

30+mpg cars dont even have an egr, so I cant imagine it helps milleage that much. (18mpg, no love from the EGR)

[240sxdrifterS14]

Thats only a problem if you live in a state thats big on emissions, and you dont have an inspectors liscense. lol

Basically, move to MO if you dont want to deal with that.

That is where I live and know inspectors even realize that it is removed, I have removed mine and never had a problem

[g6civcx]

Thats only a problem if you live in a state thats big on emissions, and you dont have an inspectors liscense. lol

Basically, move to MO if you dont want to deal with that.

No, that's federal law regardless of the state. Most states also have visual inspection on the emission components as part of state inspection.

Just an FYI in case you have a hard inspector.

[98s14inaz]

Arizona won't even pop the hoods on obdII cars. Pull in, plug in, check gas cap, pay, drive out. As long as you don't have any cel codes and your cel light functions your fine.

[Mikey88]

the egr is mainly emissions so you wont gain any extra horsepower with it plugged or removed. when you remove the egr your NOx emissions dramatically increase and you tend to run richer and in this case burn up or plug up your cat if you have it still. your car will run with no abnormal operation just richer. high NOx= high HCs and your O2 sensor may end up staying in open loop causing shitty gas mileage.

[g6civcx]

Arizona won't even pop the hoods on obdII cars. Pull in, plug in, check gas cap, pay, drive out. As long as you don't have any cel codes and your cel light functions your fine.

AZ also has an optional visual test component to check for tampering of all emission equipments as part of the emissions program.

[mxexux]

Someone correct me if I'm wrong here:

When EGR is commanded (which is typically on the highway, low load/higher rpm), your introducing an already combusted (can not be burned) mixture back into the engine, which displaces air. With less air in the mixture, the o2 sensor will pick up on a rich A/F ratio, and pull the fuel trims back, giving you better gas mileage and cooler combustion. I don't see an advantage to removing EGR unless its a track car. You won't notice a difference because when EGR is commanded, your at cruising speed under very little load.

I'm not exactly sure what Nissan's specific strategy is for EGR operation, so I don't know how removing it will affect drivability.

I'm with this guy, Removing the EGR just isn't worth it unless its stuck open and you don't have to worry about emissions. The people that remove EGR to get more power are just silly because it never operates at wide open throttle which is when people want all the power.

[mxexux]

I have been removing EGR systems for years on KAs. There's plenty of benefits, and a few drawbacks.

You are right, the engine temperature can increase without the EGR valve, the system does let cooler air into the exhaust during certain conditions to cool it, therefore cooling the entire engine. It's a limited time though, and with proper cooling, throttle coolant bypass, and items like a cooling panel or phelonic intake gasket you'll never notice it.



I'm sorry but I have to point out that the EGR NEVER lets air into the exhaust to cool it. EGR lets inert gases from the exhaust into the intake to cool combustion temp. Maybe you were thinking of the older 2-way catalytic converters with air injection solenoids that needed fresh air from the intake to light off.

[BustedS13]

Just an FYI in case you have a hard inspector.

if you have a hard inspector in this state, you drive down the street and get it done again.. inspection's what, ten bucks?

[ryguy]

I'm sorry but I have to point out that the EGR NEVER lets air into the exhaust to cool it. EGR lets inert gases from the exhaust into the intake to cool combustion temp. Maybe you were thinking of the older 2-way catalytic converters with air injection solenoids that needed fresh air from the intake to light off.

You're right. I think he was mistaking it for the AIV. The EGR does not open at WOT or idle, only at cruise, so that is the only time the EGR does anything at all. It cools the combustion chamber to lower NOx emissions. It makes one hell of a difference too, it can be the difference between a Gross Polluter and a car that passes with flying colors.

[Bigsyke]

The people that remove EGR to get more power are just silly because it never operates at wide open throttle which is when people want all the power.

I don't see an advantage to removing EGR unless its a track car. You won't notice a difference because when EGR is commanded, your at cruising speed under very little load.

I'm not exactly sure what Nissan's specific strategy is for EGR operation, so I don't know how removing it will affect drivability.

Most newer OBDII hondas dont even have an EGR valve, I think its inefficient.

I just Plugged my EGR at the exhaust manifold with a nickel. Either my EGR was stuck open, and I noticed a crack on the EGR pipe; However its an incredible difference.

I was bogging at any rpm at more than 20% throttle. Its perfect now. Just wanted to give an update.

I think this would be a good preventative thing to do in conjuction with a nismo thermostat and proper cooling.