egr blocking.

[fish]

Ive been noticing an increase in smoke lately and a noticeable flat spot in power around 2000 rpm where the turbo seemed to struggle and feel sluggish, after searching around i found this forum which was helpful.
the fellas there seemed to solve similar symptoms but blocking off the egr.

i have just done it to my challenger and have to say it is a noticeable difference. lots more power in that 2000 rpm area where before it was lame. it was dark when i tested it but couldn't see any smoke at all so i will have to confirm that in the morning. but i have a feeling that's gone too. i used 2 ml alloy plate and not a coke can as they suggested and it took me about 40 mins.
anyone tried it before here?

[callum007]

Yes, it can work. Look up EGR blocking on www.newtriton.net there is a 70 page discussion on it.

[Cameron]

did it to my teranno and holy crap what a difference.
on my wagon the egr valve was buggered and wasn't closing properly, but I'm told that even if you disable to egr on a perfectly functioning system you pick up a lot of responsiveness. plus you ditch all that crud that's going back through

[fish]

yep, well did some extensive test driving. over all a good power increase all they way across the rpm. and tho it is now raining i couldn't detect any black smoke in the mist. i would have to say im an advocate for this mod.
correct me if im wrong but in my case it seems to be a free improvement to my engine.

[4WDbits]

And clean out all the soot and crap in the intake between the EGR valve and engine.

[J_Dub]

Im very curious and interested about what it's gona do to my terrano.
Everyone raves about it, but although my truck is standard and just shy of 300, 000kms it boosts fairly well and revs fairly clean.. considering the ks its done, egr removal and an intake clean should do it wonders though im wondering if the majority of terranos dont run as good as mine standard????

[fish]

Im very curious and interested about what it's gona do to my terrano.
Everyone raves about it, but although my truck is standard and just shy of 300, 000kms it boosts fairly well and revs fairly clean.. considering the ks its done, egr removal and an intake clean should do it wonders though im wondering if the majority of terranos dont run as good as mine standard????

true sounds like you dont need to do it, mine was just running poor.

[J_Dub]

Ill still be doing it, just may not have quite the same effect

[churchill]

Done it to both my vehicles, the Focus had a faulty EGR that resulted in a flat spot at 1500rpm and heaps of black smoke over 2000rpm. After blocking it off it ran beautifully and the fuel consumption went down 0.3l/100km.

The Pajero was running fine when I blocked off the EGR so the only difference I noticed was a bit more throttle response, I'm yet to work out the fuel consumption.

[diogenese]

You will be swapping the smoke for NOx if you blank off the egr system, probably not a bad thing to do if the system is already shot but not such a good idea if it's still working.
you might want to keep an eye on exhaust temps and be prepared for cracked heads with the higher combustion temperatures. The cooled exhaust gas is fed into the intake to absorb excessive heat as well as reduce oxygen levels to reduce NOx emmisions.
I'm not trying to be a killjoy but be aware that there are no free lunches

[fish]

thanks for that info, i read a little about nox it seems that combustion will be hotter, but im confident that it wont be a danger. im pretty keen to refurb the erg at some stage and run it again to see if it is any good,
but the improvement so far is ridiculous, it honestly is like a new engine!

[Cameron]

cooled EGR is a pretty new thing.
older egr systems like guys are running here (pre euro4) aren't cooled, so by removing them, egt's will fall.
I'm cynical that even cooled egr systems drop egt temps under load. I'd say the benefits for the engine are zero when running an egr system. environment, yeah maybe. but only if the complete system is maintained, and good fuel is going in

[CLUMZ1]

worth opening the thread link (top one) and having a read thru the discussion on it

[prado_boon]

correct.

Recirculated exhaust gases will actually have a cooling effect on the chamber temprature. This is one of Toyota's reasons's for implementing the system.

Basically less gas to be burnt so there is more to the EGR system than just emissions.

[Marco Polo]

Older egr systems are uncooled like on my Rugger and the bighorn I used to own. Is it a coincidence that bighorns are known to scour the liners on 2 and 3 which is adjacent to the egr inlet? True, egr can reduce egt due to less oxygen available for combustion, but what about hugely elevated intake temps on older systems? I plan to block the egr on the rugger simply because of the amount of tarry soot coating the innards of the inlet manifold, and I'm concerned about the heat of the recirculated exhaust gases as it's a very short straight pipe run from very close to the exhaust manifold.

[timmay556]

in my prado 1zkte my intercooler is full of black shit. is this worth cleaning out with petrol?

[tweake]

you might want to keep an eye on exhaust temps and be prepared for cracked heads with the higher combustion temperatures. The cooled exhaust gas is fed into the intake to absorb excessive heat as well as reduce oxygen levels to reduce NOx emmisions.
I'm not trying to be a killjoy but be aware that there are no free lunches

correct.
Recirculated exhaust gases will actually have a cooling effect on the chamber temprature. This is one of Toyota's reasons's for implementing the system.
Basically less gas to be burnt so there is more to the EGR system than just emissions.

sorry lads but no.

in short egr reduces PEAK combustion temp but it increases EGT (cooled egr less so). the increase in egt is not always a bad thing. keeping the piston/head hot helps keep heat in the cylinder and gives back a tiny bit of power.
however the overall effect of the egr is a reduction in power, increased fuel usage and an increase of emissions except Nox. this is why modern diesels have catalytic converters and dpf's. they have to clean up all the crap the egr makes.

also that egr is typically off at full throttle, which has the highest combustion temps. blocking egr is not going to make it run any hotter than it already is. its certainly not going to cause head cracking.


one thing to watch...... some systems block the intake to reduce pressure to "suck in" more egr. if you block egr without removing that intake restriction, your reducing the amount of gas going into the engine which gives you less effective compression. especial in old worn engines that can give poor ignition and a trail of white smoke out the exhaust.

[fish]

Yep the egr draws from the exhaust about 5 inches from the block. Then it goes straight into the inlet manifold. Judging by the crapnin there when I disassembled it I cant see why I would want my engine ingesting that crap.

Note. I watched the rear view a bit today and it still smokes a bit so I still have something to fix. Injectors perhaps

[prado_boon]

sorry lads but no.

in short egr reduces PEAK combustion temp but it increases EGT (cooled egr less so). the increase in egt is not always a bad thing. keeping the piston/head hot helps keep heat in the cylinder and gives back a tiny bit of power.
however the overall effect of the egr is a reduction in power, increased fuel usage and an increase of emissions except Nox. this is why modern diesels have catalytic converters and dpf's. they have to clean up all the crap the egr makes.

also that egr is typically off at full throttle, which has the highest combustion temps. blocking egr is not going to make it run any hotter than it already is. its certainly not going to cause head cracking.


one thing to watch...... some systems block the intake to reduce pressure to "suck in" more egr. if you block egr without removing that intake restriction, your reducing the amount of gas going into the engine which gives you less effective compression. especial in old worn engines that can give poor ignition and a trail of white smoke out the exhaust.

Sorry mate I don't agree, I've talk to a few Toyota fellas and EGR's do actually creating a cooling effect.

Quote: "The EGR valve is the tap that turns the flow of exhaust gases on and off, hopefully at appropriate times.
These recycled, carbon dioxide-rich exhaust fumes cool the combustion chambers within the engine. This cooling effect lowers the combustion chamber temperature. These recycled exhaust fumes also displace some of the oxygen that would otherwise be drawn into the engine from the surrounding atmosphere. Because the combustion chamber is cooler and because there’s less oxygen, less NOx is produced."

Quote2: "The EGR valve also cools the exhaust valves and makes them last far longer (a very important benefit under light cruise conditions)."

So, this system absolutely works 100% to cool the chamber temps therefore reduce the risk of a cracked head (well in a 1KZ anyway!)

Cons:
Creates a load of crap in the intake etc
Reduces power

[tweake]

Quote: "The EGR valve is the tap that turns the flow of exhaust gases on and off, hopefully at appropriate times.
These recycled, carbon dioxide-rich exhaust fumes cool the combustion chambers within the engine. This cooling effect lowers the combustion chamber temperature. These recycled exhaust fumes also displace some of the oxygen that would otherwise be drawn into the engine from the surrounding atmosphere. Because the combustion chamber is cooler and because there’s less oxygen, less NOx is produced."

Quote2: "The EGR valve also cools the exhaust valves and makes them last far longer (a very important benefit under light cruise conditions)."

So, this system absolutely works 100% to cool the chamber temps therefore reduce the risk of a cracked head (well in a 1KZ anyway!)

i don't know where your quoting that from but not much of that sounds right.
egr doesn't cool the combustion chamber, its cools the combustion.
you have missed that egr removes the cooling effect of the incoming air which means the combustion chamber and piston temp goes up. hence egt's go up.
the reduction in air and the dilution factor tends to suffocate the combustion making the combustion cooler.
think of it this way, peak temps are reduced but average temps go up.

lastly it has nothing to do with head cracking. the worse situation is at max temps which exist at full throttle where egr is turned off. blocking egr does not change that.

both 1kz and 2lt are notorious for head cracking when egr is working. obviously the egr is not stopping the head cracking.

[slidenyo]

as neither petrol nor diesel engines are nowhere near efficient,
couldn't it be safe to assume that egr is just there to recycle a little vaporised yet unburnt fuel,
unfortunately this can be pretty laden with particulate and coke and leave a crusty black mess through the intake.

by assuming the injectors supply of fuel is metered the rate of unburnt fuel that would lift or drop egt's would purely rest on how efficiently the engine is combusting the fuel which may vary due to any number of variables (load,revs,gear selection?).
considering the reports of increased responsiveness with it blocked could be merely put down to there no longer being a port in the exhaust flow that can create an eddy or disturbance in the gas that restricts its flow or velocity.

quoted from my head

[Heath]

I find it strange that in this day of frugal fuel sipping vehicles the only way to make things better pollution wise from the factory is to lower the efficiency of the vehicle. If this lowers combustion temps by limiting air in the mix then fuel economy suffers and more unburnt fuel will be expelled (so we fit CAT converters to burn it later). OF course lots of us with turboed diesels (lets face it most diesels are turboed now) do our best to lower intake temps by fitting intercoolers and then we introduce hot exhaust fumes into the chamber - doesn't make sense does it.

Now I realise that these EGR systems are designed to operate only at idle or just above with diminishing sooty EGR gases entering the chamber as the RPMs rise, but lets face it they seldom do that unless they are new and fresh from the factory. Couple this with the oily air we draw from the crank case and introduce into the system we get a tarry mess that strangles the engine further.
Why did the factory think it would be okay not to put oil catch cans in place? And why do they still think its okay to introduce sooty air into the intake as well?

For my money it seems like the only clean and efficient way to lower temps (intake, combustion and EGT) and increase fuel efficiency is LPG fumigation. It would seem this is the answer to of diesel woes and yet not much is mentioned about it (other than is hushed corners of the net - Wary of flaming attacks I guess ).

Of course I could be wrong and just shit stirring

[fish]

What is lpg fumigation?

[Heath]

What is lpg fumigation?

Seems I have drifted of topic a little.

Very basic:

LPG fuming is when a small amount of LPG is introduced into the air prior to the turbo (regulated based on engine RPM). This LPG cools the turbo and the compressed air and the chamber. During combustion it gives a more complete burn of the fuel (Some say up to 95% instead of a normal 70ish%). The resulting more complete burn means more power so better fuel economy. Well that's what the punters tell me, I'm no expert but seems plausible.

Think of it as Nitrous oxide for a diesel.

[tweake]

as neither petrol nor diesel engines are nowhere near efficient,
couldn't it be safe to assume that egr is just there to recycle a little vaporised yet unburnt fuel,

that unburnt fuel is caused by the egr in the first place. its also only reburns a small %, the rest goes out the exhaust.

egr is only there for emissions purposes.
in petrols there is an economy effect from adding the inert gas which means the throttle can be open a bit more, which reduces throttling losses.
with diesels its the opposite as they often add a throttle to the intake which makes throttling losses.

lpg..... my understanding, tho i havn't chased up many studies on it, is that while its useful, it does increase efficiency a bit, its also very risky on the engine. power goes up but life span goes down.
the install cost undoes most of the fuel economy gains so its really only done for power.

[slidenyo]

unburnt fuel is caused by incomplete combustion its fairly lofty to claim its due to an egr system.
most direct injection diesel engines will only achieve 40% efficiency max
there are far too many variables to pin point one process as to being the cause. eg overfueling,low compression,poor timing,friction, heat...
you are however correct that only a percentage is reburnt and whether they are there to recover some of that unspent fuel for economy or emissions was up to the manufacturers engineers at the time.

imo simple is best so egr will be removed if I pickup another truck that runs it.

[tweake]

unburnt fuel is caused by incomplete combustion its fairly lofty to claim its due to an egr system.
most direct injection diesel engines will only achieve 40% efficiency max

i think your confusing energy output efficiency with combustion efficiency.
you don't have 60% of the fuel going out the exhaust as fuel.

most direct combustion engines are about 40% energy efficient, ie turn 40% of the energy value of the fuel into power output. thats with nearly 100% fuel burn. ~60% of the energy is lost as heat.

egr causes increases in C, CO and HC output. the output is exponential as egr flow goes towards a max of 50%. eg (in rough numbers) increase egr from 25% to 30% doubles the C, CO and HC output. however Nox goes down.

as Heath mentioned the systems are only good when they are new. it only takes a bit of ring wear, more blowby through the breather, blocked up intake etc to increase the EGR to a point where it makes more emissions than it removes.

[slidenyo]

no I didn't claim that 60% of input fuel makes it way out the exhaust as fuel,
energy losses through the combustion process can be heat sound friction and unburnt fuel along with mechanical and harmonic losses along with vibration etc etc.
combustion efficiency and overall efficiency are directly linked as in they can influence each other.

its by the by anyway a big theory session over the interwebs just makes for more misinformation for everyone to read and ends in talking round in circles .
I'm off to put my motorbike back together cheers Jase

[fish]

It does seem to be a very debatable topic. Tho my experience tells me that my engine if far more efficient for having it done.
Went for a long drive today to the the coromandle and it was far cleaner running than before. No isues with temp changes and noticable power increse on the passing lanes. . its a 96 mitzi so its like having a new lease on life for it haha.

[prado_boon]

egr doesn't cool the combustion chamber, its cools the combustion.

Yep the more recirculated gas that goes back into the chamber the less air/fuel there is. Therefore cooler combustion and cooler chamber/head temperatures.

EGR does more than just help with emissions although that is it's primary objective.