egr blocking.

[tweake]

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.

yet egt's rise from the removal of the cooling air.
its only peak flame temp that gets dampened. your still burning the same amount of fuel which gives the same heat output, except its cooled less when air is replaced by the hotter egr.

even IF you where to be correct, its all pointless because the highest temps are at full throttle where egr is turned off. egr does not stop the head from cracking.

[curly12]

What is lpg fumigation?

If you have some time to kill this thread will explain it and more...

http://www.offroadexpress.co.nz/Forums/viewtopic.php?f=46&t=15576

[prado_boon]

even IF you where to be correct, its all pointless because the highest temps are at full throttle where egr is turned off. egr does not stop the head from cracking.

True. And I do understand what you mean, it's just that there will be less air/fuel in the chamber and more NOx/fuel this is where the temprature difference is... but if it's hot exhaust gas (and it is) then it might be much of a muchness... I guess.

It's an interesting concept the EGR. It sure does make a difference removing the system all together don't get me wrong, it's like a new engine! But for factory diesels without intercoolers it should have a cooling effect on the combustion.

[tweake]

But for factory diesels without intercoolers it should have a cooling effect on the combustion.

not really. simply because engines without factory intercoolers are generally all hot egr. its the worse situation. hot intake air mixed in with far far hotter exhaust gas means minimal cooling. hence egt's go up.
with later model common rail engines its not so noticeable. they run cooled egr (offset a bit due to larger amount of egr used), run intercoolers and the use of variable turbo which often means they run nearly constant boost regardless of load. so they are a lot colder without factoring in combustion temp change from egr.