EGR, Whats the purpose of it......

matty · May 27, 2009

Gday guys.

Ive read a lot about people blocking the EGR but i want to know what is its actual purpose, I think i read that it helps for emissions but other than that does it do anything. Does it heat up the engine quicker, i dont know. im just keen to learn as im not quite sure if i want to block the EGR yet, Cheers guys.

Matty

Shonky · May 27, 2009

G'day Matty,

It is just an emissions thing, it lowers the temperature of the flame front in the combustion chamber which in turn reduces NO2 (Nitrogen Dioxide) emissions out the exhaust, but the jury is out on whether this actually lowers general engine temperatures as well.

What it does do is clog the inlet manifold with carbon over time which in the short term isn't a big deal, but after 100,000kms of it you might find some of the intake runners and valve ports in the head blocked with carbon build up, because of this some bores will be getting more air than others, the ones that are starving for air will run hotter until such time it melts a piston.

tweak'e · May 28, 2009

as far as heating motor goes.....
being a hot egr system what combustion heat it cools it makes up for in increasing intake temps. cooled egr systems can reduce engine temps a little bit.
however don't forget that max engine temp is a full throttle where EGR is not on.

on of the problems you get with the egr systems is the increase in intake temps increases exhaust temps. if it sticks open and is open at high throttle you can easly go over max EGT's an crack heads/pistons.
cooled egr is better as you tend just to pour out black smoke instead.

also egr reduces part throttle peformance which usually reduces fuel economy.

while EGR reduses Nox, it increases the amount of other polutants, eg CO, soot etc. hence the need for cat and DPF's.

tweak'e · May 28, 2009

one downside of blocking egr is that your flowing a lot more air through the intake system. so things like a blocked up air filter, intake temps, turbo condition will effect economy a lot more.

tweak'e · May 28, 2009

this is what egr and engine oil through the breather does.

micksbigfish · May 28, 2009

egr

so how do we block the egr fellas

tweak'e · May 28, 2009

micksbigfish said:
so how do we block the egr fellas

http://www.navara.asia/general-tech-talk/64-egr-butterfly-mod.html

Jason · May 28, 2009

How many k's on the engine that the photo's were taken from?

Dave · May 28, 2009

I remember when GUhoon posted those pics up.

That shit aint good for the motor.

Dave.

tweak'e · May 28, 2009

i would have to trawl through the forum. i do not think it was a lot.
when i blocked my EGR it looked similar and that was back at 80 tho i think.

i've seen Toyota's with 200 tho on the clock and the manifolds are 1/4-1/3 blocked. now these motors are worse due to the higher amount of EGR they use.

i was looking at water/methanol injection, it has a nice side effect of cleaning all this crap out.

matty · May 28, 2009

thanks for the reply's guys, so it is purely just a form of controlling emissions. so by doing the mod will it blow black smoke and to check the inlet manifold does the head have to come off or can you look inside the manifold by pulling hoses off or something to check the condition. one last thing, what are some of the affects on the engine by doing the mod. positive and negative, Cheers

Matty

tweak'e · May 28, 2009

doing the mod will not make it blow smoke. quite the opposite, it will stop a lot of the black smoke.

you can check the manifold by simply taking off or moving the egr tube on the inlet manifold. otherwise unbolt the inlet manifold tube with the main butterfly in it.

downsides to it.....
the turbo is used more, a bit more turbo noise. a lot more air is used so air filters will clog up quicker and dirty air filters will effect the motor more.
also you will get more diesel combustion rattle.
i've had one person who said theirs used more fuel. however it was fairly modded and had poor air inlet. i do not know if hes finished the mods and tried it again or not.

if anyone else finds their fuel ecomony goes worse i would like to hear about it.

typically on most diesel vechiles blocking the egr system off gains a slight increase in economy and plus you don't get that big build up of crap.

the biggest problem with EGR systems is when they start playing up which is not uncommon. typically they will stick open or slow to close and endup blowing clouds of smoke, crap fuel economy and at worse cracking heads and blowing pistons.

matty · May 28, 2009

thanks tweake, it sure sounds like you know a fair bit about these engines. firstly whats diesel combustion rattle, is it the loud sort of diesel sound it makes when you first start driving on a cold morning. and secondly if the egr system does start playing up it can destroy engines right, so if the mod was done and it started playing up it wouldnt really matter to much because theres no chance of the egr butterfly getting stuck open ?. Cheers

Matty

tommy222220_0 · May 28, 2009

matty said:
thanks tweake, it sure sounds like you know a fair bit about these engines. firstly whats diesel combustion rattle, is it the loud sort of diesel sound it makes when you first start driving on a cold morning. and secondly if the egr system does start playing up it can destroy engines right, so if the mod was done and it started playing up it wouldnt really matter to much because theres no chance of the egr butterfly getting stuck open ?. Cheers

Matty

Matty, i've done the mod as well.
All other reasons aside its mainly for longevity/preservation of your motor.
I think this reason alone out weighs all the negatives.

Althought i say this everytime, install a Catch Can.
For those handy with a TIG torch;
Browser Warning

Tweake, started researching water and water/methanol injection. Looks bloody good. Extra power, cleans and better fuel economy.

What are the gains like compared to Diesel gas?
(gas cleans, increases power + economy but in a different way.)

tweak'e · May 29, 2009

matty said:
thanks tweake, it sure sounds like you know a fair bit about these engines. firstly whats diesel combustion rattle, is it the loud sort of diesel sound it makes when you first start driving on a cold morning. and secondly if the egr system does start playing up it can destroy engines right, so if the mod was done and it started playing up it wouldnt really matter to much because theres no chance of the egr butterfly getting stuck open ?. Cheers

Matty

yeah rattle is like what it sounds like firs thing in the morning. tho generally not so loud.
when its blocked off the EGR valve can stick/jam all it likes and it won't effect the motor. EGR butterfly normally doesn't play up but you have to disable it if you disable the EGR valve.

tweak'e · May 29, 2009

tommy222220_0 said:
Tweake, started researching water and water/methanol injection. Looks bloody good. Extra power, cleans and better fuel economy.

What are the gains like compared to Diesel gas?
(gas cleans, increases power + economy but in a different way.)

i think the big difference here is its cheap to install. tho thats offset by to cost of the methanol as it generally costs more than LPG. mind you your not useing it straight.
proberly cost you a couple of $$ per tank of diesel for the meth. i was working on 20l per tank of fuel. @ 10% thats 2 litres of meth. if 30% thats 6 litres of meth.
not sure on the fuel economy side as it depends on how you set it up.

most of the USA guys set them up to run mainly at full noise. but small diesels your on boost all the time so you just about use it non stop hence the need for 20l tanks.

what i was also looking at is i have a supply of free sugar so i could brew my own alchohol. just working on what that will cost to do at the moment.

big problem at the moment is exchange rate. for me it doubles the price.

the other thing is how much advantage is it over an intercooler. that no one seams to give fiqures

tommy222220_0 · May 29, 2009

tweak'e said:
tho thats offset by to cost of the methanol

About $AU 220-250 for 205L from local chemical supplier.

Wonder what water alone is like?

tweak'e · May 29, 2009

not sure what water is like on its own.
water cools the combustion while methanol burns and ads heat.
the good thing with methanol is it will evaporate even when the water can't, so adding methanol gives you much more evaporative cooling than water alone.

tommy222220_0 · May 29, 2009

yeah, Its good when you realise all that time spent in chemistry lectures wasn't a waste.

Need someone to do some independant testing.......

tweak'e · May 29, 2009

thinking about it, these turbo's out put should be well over 100 degrees, so water will just turn to steam. this will cut down the amount of cooling the combustion chamber and not have loss of power.

the big question is it worth doing or is fitting an intercooler a better use of the $$$$.

EGR, Whats the purpose of it......

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