Exhaust Gas Recirculation..... to keep or not to keep

[78Suburban]

Should I keep the EGR on the motor I am swapping in, or just block it off with a plate? Emissions are of absoultely no concern to me, I just want my motor to run good, not too lean or rich. Currently the EGR unit is off the motor. I'm not really sure where the little metal hose end on the unit connects to , does it connect to the exhaust manifold via a rubber hose?
Thanks,
James

 

[sled_dog]

the little metal nipple? Believe it goes to manifold vaccum. I say keep it. EGR doesn't hurt performance. It does nothing at WOT(thus the vaccum port). Some engines may run better with EGR. Eh thats what I was told, never tested the theory. I took it off my 84 K5 before I knew any better. Never noticed any difference, personally if its not hurting performance I don't see a reason to remove emissions stuff. Its really not all evil, I like not hurting the enviroment... well a little less.

 

[GotBoykins]

Get rid of it, it takes up too much space on the manifold. Besides, it is always nice to remove something and not have to reinstall or replace it.

 

[drofdar]

I have been told that the EGR valve does exactly what it says, recirculating exhaust gas back into the intake. If it is blocked off, then your engine will run cleaner, and less throttle is required for the same power, meaning better mileage. If you run injection, then the chip must be reprogrammed to account for the lack of EGR. Since I am not an engineer, I am only repeating what I have heard. If others have a better understanding, please chime in, I'd love to learn more.

 

[78Suburban]

leaning toward leaving it on

since it doesn't hurt performance I think I will put it back on

 

[sled_dog]

EGR does recirculate exhaust gas. It takes exhaust gas and places it into the intake tract so it is put into the cylinders. It is already burned so it is an inert gas and just takes up space in the cylinder. This makes for a cooler burn and yes less power production(at part throttle when it is actually working). The cooler burn lowers emissions(NoX is created during high combustion temperatures and a nasty emission I might add.). So I guess the statement it "doesn't hurt performance" is incorrect, but the statement, "you won't notice the power increase" or "no reason to remove on a non-high performance application" are more accurate. Like I said, at Wide open the vaccum signal to the EGR valve is gone and it closes off, meaning all of the cylinder is full of fuel and air, none of the inert exhaust gases.

 

[78Suburban]

c'mon, I know a few more people than have voted, have an opinion. Tell me why I am an idiot if I do or don't.
Thanks,
James

 

[Cornfield creations]

Since the EGR recirculates exhaust through the intake, wouldn't that heat up the intake, and in turn heat up the air charge going to the cylinders? Which a cooler more dense charge is what we are after for maximum power output.

 

[muddyblzr]

if you live in a cold environment i say keep it. i just figured out why my truck idled so high in the morning and its because mine was taken off. When its super cold outside if u have the EGR it will run better cold. its only cold around here for a few months so im not too worried about not having it.

 

[GotBoykins]

Come on, its a tie! Someone convince him one way or the other!

 

[hack500]

on a stock engine blocking the EGR in the intake will cause the motor to run a little bit leaner.

 

[drofdar]

Sled Dog

Good info. So, with a motor designed to give good power in the low end.. ie: off idle to 1500 rpm, say rock crawling, or low speed sand, then blocking off the egr would be helpful. But at wot such as mud bog or all out desert racing, Baja style, then blocking the egr is meaningless. Therefore, the answer depends on the mission of the power plant. Since I rarely use the floor as a pedal stop while offroad, I have my egr blocked and the chip on my tbi reprogramed accordingly.
These kinds of things make it so hard to give a definative answer, no?

 

[diesel4me]

Your results may vary...

I don't think EGR valves help performance any..they do kill some HP --and were invented as a crutch to help "dirty" motors pass stricter emission standards..I have removed a few on my vehicles..my Edelbrock carb would not bolt up to the stock Q-jet intake,even with the adapter/spacer--because the "toadstool" was in the way..
(thats my friends nickname for an EGR valve! )..

So off it went,and a block off plate went in its place..A few motors I've had protested its removal by pinging..had to retard the timing some to keep it from damaging something,like pistons,negating any gain in performance by removing it.. I have gained a few mpg by disabling them,as long as I could get away with leaving the timing set to spec,or slightly more advanced..

My diesels EGR valve was disconnected when I got it..I don't plan on hooking it up again..of course,diesels EGR works different than gas anyway..its EGR valve is OPEN at idle!---just the opposite of a gas motor..which uses PORTED vacuum in most cases,BTW..not manifold vacuum,depending on what type of EGR valve it has..(positive backpresuure,etc..)

A gas motor also uses a thermostatic vacuum valve to operate the EGR valve--so its disabled until the motor(or coolant) reaches operating temparature,to prevent stalling or surging..so it has no effect on cold engine operation....

 

[eagle mark]

The EGR let's in very little exhaust, just enough to change the output of emmissions as mentioned above, which is not a bad thing. Good clean air we can all deal with.

The reason you see some pinging after removing one is because it totally changes the advance curve needs!

 

[sled_dog]

These kinds of things make it so hard to give a definative answer, no?

Definitive answers are always hard to come by in the performance world. Most of the time when someone says "Always" or "Never" someone soon comes along and discredits that.


Cool intake is nice, but there is a point of too cool. If the intake gets too cool the fuel won't atomize properly and you will have crap for power and throttle response. Everything is a fine line when it comes to performance. Personally I'd prefer to keep my intake just a little warmer(maybe use a thin carb or TBI spacer to keep my injection point a little cooler) and err on the safe side. Most fuel injected motors are meant to run warmer all around.

 

[78Suburban]

Is this logical?

Eurika! I think I've come to a conclusion.... I really don't think it will significantly affect perfomance on a stock motor... If I put it on, and the valve happens to be malfunctioning, or plugged..... then that is no different than putting a block off plate on the motor.. so really, I have Nothing to loose by getting an EGR gasket, and throwing the old EGR back on the motor... oh yeah, and a little rubber hose to run it to the carb...
But, I've got nothing to loose, right? does this make sense?
Thanks,
James

 

[dyeager535]

So, with a motor designed to give good power in the low end.. ie: off idle to 1500 rpm, say rock crawling, or low speed sand, then blocking off the egr would be helpful.

No, not true. It takes VERY little engine load to decrease the amount of engine vacuum, so EGR would be very ineffective during that condition.

Not to mention, on a Quadrajet EGR is "timed" and is only going to POSSIBLY get an EGR vacuum signal when the throttle blades are at a certain position.

 

[Inu-Hanyou1776]

I say keep it. The power loss is negligible even under part-throttle, and the air stays a little cleaner thanks to it too, which we all could use.

 

[yagsinairod]

remove the EGR and it will run better

 

[sled_dog]

your only problem is if it fails open and constantly is working. It happens from time to time, they can carbon up like that. But I don't think a new one is expensive. I've removed them a few times, but in the future I doubt I will... at least from lower performance motors.

remove the EGR and it will run better

Thanks for the insight.