has any body disabled their egr on a 5.4l for any extended time. does this have a bad effect on the engine? longevity?

please dont post how this would be illegal, speeding is illegal, drinking as a minor was illegal i could go on and on. im just wondering what the effect would be from someone that has done it.

i am very aware of the theory. the combustion temps may go higher but would the fuel economy get better? remember that egr is off under wot and high load. so it cant be that bad to turn it off.

just wondering.

 

You can turn it off but you will most likely have pinging issues at part throttle since it is calibrated for the EGR flow.

 

EGR helps with fuel economy by reducing pumping losses of the engine. More EGR at cruise=better economy. Reduced combustion chamber temps also mean you can run more spark advance for a bit more torque at crusing speeds to reduce the load on the engine.

 

could diablo rework a tune to compensate for the loss of egr? i would like to see the fuel curve while operating egr.
if you add heated nox to the intake as egr does then they have to compensate by adding fuel or retarding timing. i dont buy that they lean out the mix and advance the timing to get better performance.
egr only lessens the egt by a couple of hundred degrees. less egt is a loss in performance. egr is about reducing nox not performance.
i think thats why the manufactures have had to disable egr at high load and wot. its the only way that they can sell the system by saying that it is a plus in the performance dept.
why did older more powerful engines that were properly tuned give the same hp and better mileage than today.
these trucks are terrible at mileage.
i work with egr systems every day in diesel systems and some gas. they do not give increased performance or fuel economy. period.
the power of the pcs and sensors in todays engines would be better suited to running the engine than monitoring and changing parameters to suite emisions.
i guess that the gov is un willing to make the oil companies make a cleaner product for the enviorment. so we burn more fuel to have cleaner air (???)
remember the propane conversions back in the 80's, they gave very clean air and (less) but ok performance.
where would we be now if the oil companies and auto manufactures were forced 20 years ago to devolp that technology?

 

What you know about diesels does not apply to gas engines.
EGR INCREASES FUEL ECONOMY on a gasoline engine.
It does this by reducing the pumping losses by recirculating exhaust back into the intake and effectively decreasing displacement. It's not used at WOT because of this effective decreased displacement and the loss of power that would come from it.
Several OEM calibrations use a spark adder per % EGR flow.
I'm not gonna argue it anymore-I've seen it,I know it is a fact from experience.
JL

 

the diesel and gas egr system is used soley for emmisions. they work on the exact same principal and they work identical. im wiling to learn. so show me that the egr increases mpg. not the theroy. older egr systems admitily reduced mileage and power. but new ones because of advanced tecnology have less of an impact that we see. but wouldnt they advances be better used if we used better fuel.
you want to talk about differences in gas and diesel. check out the change in sulphur in diesel fuel over the past few years. gas hasnt changed in 30 yrs and you think that the theroy for its combustion is better now. no its the electronic management and the publications. i will change my opion (based on my experience and published knowledge) if you can convince me that egr improves fuel economy. you already admited that it does harm power.

 

What part of this do you not understand?
It does this by reducing the pumping losses by recirculating exhaust back into the intake and effectively decreasing displacement.
It's very simple.
JL

 

man you need a hug or something.

in your little world that may make sense and you probably understand it. but if you understand the reason for egr and the concept then you would realize that the effect it has does not reflect a smaller displacment. egr puts un usable element in the combustion process, gasses from the burnt exhaust back into the intake. by removing the oxy component in any part you effectively keep the compustion temps down. provided you manage the mix to avoid a lean burn which starts a "ping". by carefully measuring the mix you can controll the temp to a desired level. below a certain level you dont create the evil nox.
the effect is that the engine needs constant changing fuel and air to keep running at all. the fuel mix is constantly being adjusted to meet emmision pre set paramteres.
i would love to find out what the actual fuel curve is in real time while running egr.

if you just decreased displacement you would have the same combustion temps. if you want to discuss this in an adult manner, you first have to act adult. if you disagree or can add something constructive please do. if i have po'd you some how and this upsets you then sorry, but please dont post something if you dont know what your talking about.

 

I'm sure Diablosport could write a custom tune to run without the EGR. I don't know what you will gain from not running it.

 

i guess thats what im wondering. what would the gain be? with a new program for no egr.

 

Nope, EGR is disabled at WOT and high loads because it's worthless at that point.

The large cool air charge at WOT or high loads (open throttle) will bring down the combustion temps on their own. The only times EGR is required is light throttle.

I don't buy the fuel economy argument of less pumping energy required...

The only thing EGR does is reduce NOx (oxides of nitrogen) ... formed by the nitrogen in the atmosphere being heated and bonding with oxygen.

The benefit of the EGR is reduced combustion temps - letting you (and the PCM) advance the timing MORE without pinging and get more energy out of the burn.

 

"effectively"
www.dictionary.com
I'm done with this.
You obviously know so much more than me about the control system since you're asking questions about things that even novice tuners and simplistic shadetree hacks know.
JL

 

as im chewin on my straw, with me fingers in my over-all straps watchin the hound dog just younder off me porch i thinks. "good im glad your done". your not constructive anyway jl".
thank you krewat. but why then are egts thier highest at wot 100% load? for along time i have preached to guys who build up their engines for racing and street about cool air intakes. now that they are becoming a reality and easily assesable the advantages seen by the racers and the streeters in the past are filtering down to the novice tuners and simplistic shadetree hacks.
i cant help but go back to the cleaner fuel for emmisions that wont harm performance. i think it wont be long before you see intake air coolers operating like an ac system in the intake to recover some of the lost power and economy from the current systems. plus i see charged air systems becoming the norm for efficient and powerful combustion while maintaining economy.
15 yrs ago a 50mpg car on pump gas was a pipe dream. were starting to approach the max thermal effiency of gasoline in these engines where there simply isnt any more we can get out of gas hydrocarbon with todays technology and designs. does any one think that means they wont get better mileage in the future? i hope not. the problem for me is that we have accepted poorer mileage in bigger vehicles just because there bigger and work harder. i dont think thats ok. our emmisions are cleaner but fuel economy is the same or worse than 20yrs ago.
check out some of the stuff comming out of europe, diesel espically. unreal what they can get for mileage and power.
just because its the way the goverments and the auto manufactures say is the best isnt good enough for me. but i guess there never wrong..lol.

 

EGT's are high - but is the temperature inside the combustion chamber that hot?

Maybe I'm wrong on the cold air charge at WOT - maybe it's more that there's just no way to inject anything into the combustion chamber to lower temps at WOT?

--

Let's keep it civil.

 

civil good.
theres a newer system out that "catches" the nitrogen particles in the exhaust and after it all but fills up it recycles it into the intake. kinda like egr but less constant. allows for higher combustion temps with out sacrificing power. that system with a coates head design might be the way for todays technology. way more effiency and good emmisions.
im just looking for input. i know that the change in the older engines had to do with the change in allowable compression ratio's due to the change in lead additives. we went from around 15:1 to 9:1 over night. the combustion effiency went out the window and the economy followed. they had to do this because at 15:1 on un-leaded you exceed 2500f at normal operation. someone else can give exact numbers for sure but i know that these are close. at 9:1 thermal effiency is less than 33% and we still make nox. again i go back to a different fuel source.
but for now i still cant rap my thick skull around what taking the egr and reprograming for that would actually do. its not a cheap proposition if i run the pistons out the exhaust becasue the things are designed for lower combustion temps. but in my thinking removing that egr would allow for a better burn. if properly calculated. i know that there is someone here that knows what im trying to figure out. i just want to know.