Outer Limits 4x4 Board

What is an EGR, and what does blocking it do?

Exhaust Gas Recirculation

recirculates exhaust gas back through the inlet manifold to lower combustion temperaturs.

actually it recirculates exhaust gas back throught the inlet to lower emissions .

stool wrote:Exhaust Gas Recirculation

recirculates exhaust gas back through the inlet manifold to lower combustion temperaturs.

And as a few grenade users found out blocking it on the 3.0 GU causes mass exhaust temp issues. as if it doesnt have enough issues already.

bogged wrote:

stool wrote:Exhaust Gas Recirculation

recirculates exhaust gas back through the inlet manifold to lower combustion temperaturs.

And as a few grenade users found out blocking it on the 3.0 GU causes mass exhaust temp issues. as if it doesnt have enough issues already.

not quite.

the problem with the 3.0 ZD30 in the patrol is blocking the EGR causes the variable turbo to over rev and produce large amounts of boost and lots of back pressure against the motor. this is why they have to adjust the turbo to suit. once thats done its not a problem and exhaust temps actually decrease.

EGR basically snuffs out the flame a bit. it decreases the peak flame temp so nitros oxides are not made.
the down side is other pollutants are increased as well as large amounts of soot. this is why motors that use large amounts of EGR also have a catalytic converter to clean up that extra pollution and later ones also have soot filters on the exhaust.
EGR valves are well known for not working correctly which often means excess EGR can be shoved in which you might notice from the black smoke produced.

blocking the EGR means less soot produced, less soot goes into the oil (big problem with high stressed diesels such as the ZD30), better drivabilty and better economy.
however it will produce more NOx, a bit more wear on the turbo (due to it reving a bit more) and more air flowed through so your airfilter will clog up a little bit quicker.

tweak'e wrote:however it will produce more NOx, a bit more wear on the turbo (due to it reving a bit more) and more air flowed through so your airfilter will clog up a little bit quicker.

and highter temps. 2 dudes on exploroz with EGT Gauges scoring high 680's were not having problems, considering this was only highway (Central aussie style hot ambients) work. its just something to be thoughtful of if your unlucky enough to own a grenade in the first place.

bogged wrote:

tweak'e wrote:however it will produce more NOx, a bit more wear on the turbo (due to it reving a bit more) and more air flowed through so your airfilter will clog up a little bit quicker.

and highter temps. 2 dudes on exploroz with EGT Gauges scoring high 680's were not having problems, considering this was only highway (Central aussie style hot ambients) work. its just something to be thoughtful of if your unlucky enough to own a grenade in the first place.

you only get higher temps if the turbo is incorrectly adjusted. either they where running too high boost or they adjusted it to much and where running really low boost. edit: there is a bit more to it as the turbo is controll mainly by the MAF sensor which has a habit of playing up. also some turbo's have been known to stick or sieze the vanes into position.
i'll bet they had other problems which is why they got werid results.

also it depends on WHERE they are measureing. because its a variable turbo the temps after turbo do tend change depending on how the turbo is setup.

think about it, if your reducing inlet temps egt temps must go down. shoving hot exhaust gas in the inlet is not going to cool it down.

aren't exhaust gases cooled first before entering the inlet

tweak'e wrote:

bogged wrote:

tweak'e wrote:however it will

produce more NOx, a bit more wear on the turbo (due to it reving a bit more) and more air flowed through so your airfilter will clog up a little bit quicker.

and highter temps. 2 dudes on exploroz with EGT Gauges scoring high 680's were not having problems, considering this was only highway (Central aussie style hot ambients) work. its just something to be thoughtful of if your unlucky enough to own a grenade in the first place.

you only get higher temps if the turbo is incorrectly adjusted. either they where running too high boost or they adjusted it to much and where running really low boost. edit: there is a bit more to it as the turbo is controll mainly by the MAF sensor which has a habit of playing up. also some turbo's have been known to stick or sieze the vanes into position.
i'll bet they had other problems which is why they got werid results.

also it depends on WHERE they are measureing. because its a variable turbo the temps after turbo do tend change depending on how the turbo is setup.

think about it, if your reducing inlet temps egt temps must go down. shoving hot exhaust gas in the inlet is not going to cool it down.

marko wrote:aren't exhaust gases cooled first before entering the inlet

no.

only the latest CRD patrol has cooled EGR. all others in AU/NZ are hot EGR.
also even the cooled EGR is only cooled down to engine coolant temp, so its still going in at 90 degrees.
the main reason for cooling it is to increase the amount of EGR (due to the EGR being denser) going into the motor.

tweak'e wrote:you only get higher temps if the turbo is incorrectly adjusted. either they where running too high boost or they adjusted it to much and where running really low boost. edit: there is a bit more to it as the turbo is controll mainly by the MAF sensor which has a habit of playing up. also some turbo's have been known to stick or sieze the vanes into position.
i'll bet they had other problems which is why they got werid results.

also it depends on WHERE they are measureing. because its a variable turbo the temps after turbo do tend change depending on how the turbo is setup.

think about it, if your reducing inlet temps egt temps must go down. shoving hot exhaust gas in the inlet is not going to cool it down.

Stock grenades with 3inch xhausts.. no turbo or pump mods...