Does an EGR valve matter?

[micondie]

For a good article on what an EGR valve does and how to modify it try here: Browser Warning
Autospeed is an excellent source for good info on mods. They are great for testing theories and separating the true from the crap.

[Mario_Marques]

Originally Posted by mwebb

...This is good and bad. Bad because EGR always , always hurts power and fuel use, always. "...
EGR is good -
in a system that is functioning as designed
EGR does not reduce power output and EGR does improve fuel economy by recucing suction throttling loss .

the ECM does not allow EGR operation when power is needed or when the system is at idle .

so
those who defeat their EGR systems are
DECREASING THEIR FUEL ECONOMY and INCREASING NOX EMISSIONS
while
doing nothing to improve power output

it's true and I did the test on my own car for reasons of modification of the intake manifold, I had to remove my egr, immediately noticed the car's onboard computer a fuel consumption increase.
This increase is specially noticeable in winter, cold or city driving at low speed(when egr is working, at full throttle egr is closed).
But there is two sides of egr, some people has clogged egr's, when this happens, the fuel conumption increases more than if you dont have any agr, and ther's a(big in some cases) performance loss, it's not noticeable because its progressive whit the years, only noticeable when you clean the egr.

There is some examples os cars that i have cleaned and worked the egr and intake manifold:


By mario_marques at 2009-04-08


By mario_marques at 2009-04-08


By mario_marques at 2009-04-08

Cleaned:

By mario_marques at 2009-04-08


By mario_marques at 2009-04-08


By mario_marques at 2009-04-08

Well, after i cleaned it my clients claim a very nice gain of power and less fuel consumption, the exhaust smoke also reduced for no smoke at all(diesel cars...), i also cleaned all intake pipes(and in those cases the intercooler because was dirty and has a lot of oil inside) and replaced the ccv filter.
This systems, egr, katalitic converter, dpf, etc are very nice but they need to be inspected and cleaned, if you dont clean it, you will spend on fuel a lot more than you pay for cleening them.
I also polished the egr(to prevent for get dirt again), i polished the intake manifold ducts and thermo coated whit ceramic tint(tho prevent them for eat and i've worked the air ducts(oversize them to match the engine head port, gains a little performance to, with more performance at low speed your fuel mileage will increase too )

[Jim-Bob]

On engines that come with it you definitely want it to be functioning. I know that on the Nissan KA that if you do not clean out the EGR jet ports on the intake manifold every so often the engine will miss and run rough at idle. Fortunately though there are clean out plugs for them on the intake manifold and all you have to do is unscrew them and run a long, sharp awl through them to clean them out.

On the Suzuki G10 in the Metro/Swift/Firefly/Barina/Cultus, a poorly functioning EGR system (when used) will cause the engine to burn the exhaust valves because they will run too hot. Not only that, but it will negatively impact fuel economy as well. The computer is programmed with the EGR in mind and removing it can cause engine damage.

[stovie]

i have a 1997 jeep grand cherokee that has what looks like a egr delete but i'm not sure the manual says that it's supposed to have one but there's no hole in the exhaust manifold(i think the owner before me got a header upgrade that had no egr port so he got a delete but not sure???) and i'm getting the same fuel economy as listed on the epa website stock???? any ideas???(and i'm not getting any ecu trouble codes so i think it's supposed to be vacuum operated)

[mwebb]

read
the
EPA emissions system tag under the hood

the tag will list all of the emission systems that your car was born with
if it shows
EGR then your system was born with EGR if not ....

do the math

[cRiPpLe_rOoStEr]

Originally Posted by Mario_Marques

I did the test on my own car for reasons of modification of the intake manifold, I had to remove my egr, immediately noticed the car's onboard computer a fuel consumption increase.
This increase is specially noticeable in winter, cold or city driving at low speed(when egr is working, at full throttle egr is closed).
But there is two sides of egr, some people has clogged egr's, when this happens, the fuel conumption increases more than if you dont have any agr, and ther's a(big in some cases) performance loss, it's not noticeable because its progressive whit the years, only noticeable when you clean the egr.

The problem removing the EGR is due to the stock ECM flashing error codes and running on a different injection map like the engine had a malfunction. I've already seen some EGR disabling plates mounted between the EGT sensor and the EGR valve which actually led to increase the fuel-efficiency, and even the turbo had more boost from lower RPMs.

[Mario_Marques]

In some cars you dont experience that kind of problem, i already try this in a lot of european cars and no lights on dash, not even dtc when you check up the ecu.
But removing the egr is not the best solution has i told before, the best choice is to keep it, and service it to keep it clean and work perfect.
I didnt notice any performance gain in cars with good egr removed, i only feel difference when i romeved damage or cloged egr, in this cases you can feel a gain, but this gain is not in fact a gain, you're only getting the performance you did lost before.

[cRiPpLe_rOoStEr]

Originally Posted by Mario_Marques

I didnt notice any performance gain in cars with good egr removed

That's strange. But the 5% average fuel-economy increasement is more noticeable than performance gains