anybody ever remove their EGR valve ?

[joe88xj]

I have`seen posts in the past where guys have remove their EGR vale and fabbed a plate to block off the opening,not on jeeps or the 4.0 though just wondered if anybody has done this and what the results were, any performance gains? losses? etc etc

 

[yellowxj]

I've wondered that too.

 

[old_man]

There are no significant hp changes with the egr. It keeps the combustion temp down, to control the emissions. I would keep it just to keep the engine temps under control.

 

[joe88xj]

doesnt it send warm gases back into the intake from the exhaust manifold? wouldnt this make the engine run hotter? i thought the theory behind removing the egr is cooler intake temps= more horsepower.

 

[CheapXJ]

I blocked mine off when it failed.

I wouldn't do it for a power gain, you won't get one

the one thing I did notice is that my intake and injectors stay MUCH cleaner

 

[pperelman]

BASICS of EGR valve.

THERE IS NO POWER GAIN FROM REMOVING IT. EGR OPENS ONLY AT CERTAIN RPM (NORMALLY HIWAY SPEED) TO THROW SOME OF EXHAUST GASES TO COOL DOWN COMBASTION CHAMBER, THUS REDUCING UNWANTED HEAT BULD UP DURING NORMAL ENGINE LOAD. IT MAY OPEN DURING HARD ACCEL (BUT RULE OF THUMB) IT WORKS MOST EFFICIENT AT HIGHWAY SPEEDS....NOX IS WHAT CAUSES TEMP TO GO UP....EXHAUST GASES REDUCE NOX....
BASICS....PEACE.....
A GOOD EMISSION TECH AT SMOKE-CHEK WILL SEE ABSENCE OF EGR .....FAILURE !!!!!

 

[XJ-ARMOR]

Actually, some east coast jeeps came with a factory...yes factory blocking plate. Depending on the delivery destination and regulations for the state/county. (I believe New York had backing plates in early 90's) The EGR does decrease combustion chamber temps. I would disagree on one common statement made by a few so far. The removal of the EGR --WILL-- increase performance. This may only be a couple, or a few horse, and may not be felt on most circumstances, but there is a gain. The EGR is dumping exhaust back into the intake from about 1500 rpm on up...if you look at the EGR actuator while the engine is running you can see the actuator moving with ever blip of the throttle. All these gasses recirculating into the intake dissipate clean air. Since cold air is dense air, warmer air = less HP. -Steve

 

[joe88xj]

thats what i thought about it but wasnt 100% cooler air is better , what i dont understand is how the egr cools the intake since it is recirculating spent hot exhaust gasses

 

[Bender]

The reason people say you don't see a performance benefit has to do with the EGR being shut off by the computer under open loop mode i.e. wide open throttle.

Generally when someone is checking for a permormance gain they are really giving it and have the throttle all the way down in which case the EGR is automatically closed. Removing it will have no impact in this situation.

The EGR is also closed during the engine warm up time.

 

[JeepSpeed]

thats what i thought about it but wasnt 100% cooler air is better , what i dont understand is how the egr cools the intake since it is recirculating spent hot exhaust gasses

The EGR puts the exhaust gases in to cool the combustion chambers. Exhaust gas is hot, but combustion chambers are alot hotter.

Also, i'm no expert, but from what I understand of Exhaust Gas Recirculation, it isn't used during full throttle acceleration, but more during cruising. Therfore, blocking it will not improve performance where u want it to. It might give half a horsie when u are cruising down the highway, but if u want it back that bad, accelerate please.

Also, still no expert, but I beleive it helps engine life by cleaning the combustion chambers. Sorry if someone proves me wrong on any of this.

 

[TiRod]

Well, I remember when EGR first started in the 70's. The reasoning then was to recirculate the exhaust to further burn hydrocarbons and clean the overall emissions. Carburetors not being very precise, ya know.

Adding hot exhaust to the cold intake stream, IMHO, raises the temperature of the intake charge and adds unburnt emissions. Both do not increase performance. No one runs their exhaust right back into the air filter, even if they added O2. The factory adds exhaust into the intake stream under part throttle conditions because power demand is less then, and the reduction in HP isn't as noticeable. Also why it's cut off at full throttle - you need power.

"Cooling the combustion chambers" smacks of internet mythology - I'd really like to know where this one started - so I'll go search now.

PS - if exhaust gases cooled the combustion chambers, why not increase EGR in turbocharged cars rather than install expensive intercoolers?

 

[TiRod]

Found this:

EGR is considered a `metered intake leak' and was developed to reduce the combustion temperatures to below 2,500 degrees, the threshold where NOx is created. Not unlike putting a brick in your lavatory to lower the volume of water used, the EGR valve meters a readily available inert gas (actually exhaust gas which contains a lot of very inert Carbon Dioxide) into the combustion chamber to effectively reduce the volume. Smaller effective displacement means less fire, and less heat and thus lower temperatures, thereby controlling NOx emissions.

It came from www.fordscorpio.co.uk/egr.htm

Very informative - the exhaust gas isn't cooling the combustion chambers, it displaces combustible gas from the intake reducing the overall combustion temps. This doesn't sound like a power maker.

Moot point for some - but you weren't saying it wrong, I was taking it too literally. :anon:

I took mine off my old F150, but if its working, why waste time messing with it. There are other mods to gain more HP and many of us must have it to meet sniff tests and visual inspection.

 

[BUCKYXJ]

Mine is disconnected but I only did it because it was causing the jeep to stumble and die when I pressed on the throttle. I would not unhook it unless it didn't work. Mine has been unhooked for a little over a year now and no problems. DIG IT!

 

[TiRod]

egr makes hp?

I'm filling up a plate of crow . . .

from www.sethirdgen.org/egr.htl

Other notes: Most people like to disable the EGR because they claim that hurts performance. In actuality, disabling the EGR can hurt performance. Here is why.

As we already know, at certain thorttle postitions and RPMs, the ECM will command EGR operation. This is to cool combustion chamber temps under load. Well, with cooler combustion chamber temps, we can further fuel economy by advancing the timing. We know that to much timing will cause “pinging”. But when we keep the combustion temps down, the timing can be advanced without the “pinging” effect. At highway speeds, the ECM commands EGR operation and will advance timing accordingly.

With a blocked off EGR, the computer thinks it is flowing when it is not and will advance timing. Now that the combustion chamber temps are much hotter, the advanced timing is no longer a good idea and detonation occurs. Since detonation can severly damage an engine, knock sensors are used.

When the knock sensor detects detonation, it will retard timing. It takes more to stop detonation that it does to cause it and this is where it hurts performance. For example, at highway speeds, your total advance may be, lets say 30* BTDC. If the computer advances it one more degree to 31* and it detects detonation, it can’t just go back to 30* to stop it, it must retard timing to like 25* to try and stop it, and if it still occurs it will further retard timing. If the EGR was working properly, the temps would have stayed cool enough to operate at 31* with no problems.

In short, lower temps allow more advance = more hp.

I've learned something today.