Compression and then decompression of burning mixture is irrelevant.
Of course when we compress air it warms up and then cools down on decompression but sum of energy is zero.
It's not heat that does work (push piston) but pressure.
Heat is just there to produce pressure.

Peak combustion temperature reach 2200C and average is around 1500C (gasoline).
This is how hot burning gasoline gets.

It doesn't matter if you ignite mixture earlier or later. It burns at around 2200C.

The longer heat stays inside cylinder the more is absorbed by the engine (pistons, cylinders, valves) so they are more heat stressed.
Its that simple

The more heat absorbed by the pistons and cylinders the less is left to be thrown out thru exhaust.

That's why you advance ignition and "magically" EGT goes down.
And when you retard ignition EGT "dangerously" goes up.

Bute there is the same amount of heat produced as long as the same amount of mixture is burned.
So what EGT sees is not relevant to heat inside engine.

Well given the same conditions like the same ignition, AFR, rpm and amount of air EGT is relevant to heat inside engine but when you change one condition like ignition angle you change EGT but actual amount of heat is the same.

For example, imagine we stop engine on the combustion cycle with mixture compressed inside and we ignite it.
It will burn and go out. What will happen with heat? All of it will stay inside cylinder. After a while engine block will absorb all of it - simply speaking we just heat up our engine a little.
Now imagine we have multiple burns one after another. and engine rotating. It will still heat up engine but this time some of it will also be ejected thru exhaust.
And now depending on how long mixture will stay burning inside (ignition angle) the more will go into heating engine block (pistons, cylinders) and less will be thrown out of the engine thru exhaust.

Another thing. If you cruise slowly on low rpm mixture still burns at 2200C (gasoline doesn't know your car goes much slower and have to burn with half of its normal temperature:) But your EGT will be like half of what is on full power. Why? Because flame stays a lot longer inside engine and more of it's heat is absorbed by the engine then is thrown away comparing to full power scenario. Of course thermal stress is also way lower because we burn much less amount of mixture.

I can't put it more simply I hope my english is not that bad either

Yeah sorry for my english, heat transfer soundes better
But EGT probe in the exhaust measure temperature... in the exhaust Not in the cylinder
As i said you can have more heat inside cylinder and less outside and other way around

I was taught other way around
Retarding ignition cools cylinder.

Combustion heat balance looks more or less like this:
1. 30% - is lost with exhaust
2. 30% - is lost into cylinder (heats up engine parts)
3. 30% - is what actually heats up air producing pressure

Heat 1. is exhaust stress.
Heat 2. is engine internals stress (pistons, cylinders, valves)

The more you retard ignition the more heat goes into 1. and less into 2.
So you simply cools cylinder But at the same time you heat up exhaust parts
For example - launching ALS - you see massive EGT rise but you also cool down cylinders - but you do not see this because you do not have temp. sensor inside cylinder.

Fun fact - we had test engine in the lab with temperature and pressure sensors installed and they were very accurate and even more expensive
No one cared about EGT temperature in the lab What was important was temperature inside cylinder (and pressure).

But because we do not have NASA like equipment available for our cars so we put primitive cheap EGT probes inside exhaust that do not tell us much about what is going inside engine but that is all we have
It's like watching distant galaxies with telescope - we can't go there personally and measure anything directly so we just observe it from far away and make assumptions what is going on there

And again "kinetic" energy is related to speed when body with certain mass is moving.
There is no kinetic energy extraction from combustion
Burning mixture has no kinetic energy and does not do any work. It just heats up medium (itself).
As i said there are engines that have external heat source like Stirling engine.
Stirling engine has no intake or exhaust, medium is closed inside.
You heat it up externally by heating cylinder walls!
And it works like ICE engine - all that matters is pressure - how you get pressure is irrelevant.
And as for thermal waste i wrote about it above.

Preignition or detonation is another topic.
Mixture ignited normally (with spark plug) burns quite slow at constant rate - so that why you advance ignition with engine speed.
But when too much heat or pressure it can self detonate and it causes more heat and more pressure and more self ignition occurs.
Then pressure inside cylinder goes crazy (jumps violently all the way around) and combustion is disrupted.
For example if you put too "hot" plugs they do not transfer enough heat off the plug itself to the head so they get too hot and start working like glow plugs in diesels pre-igniting mixture.

btw. this discussion made me refresh some knowledge from studies that i started to forgot:)

Exhaust valves and exhaust ports are also "exhaust parts".
Retard ignition in steady state and you focus so much heat on this area that you melt it or drop a valve resulting in engine failure.

This statement is incorrect on it's own.
Combustion temperature decreases in both directions of stoichiometric. The hottest burn is at stoichiometric ratio.
Rich mixture in case of liquid fuel has also the advantage of evaporative cooling...

Also in the real world you will almost never melt anything but the exhaust portion of the combustion chamber in case of normal combustion.
So minimizing EGT is a very good tuning strategy. The whole heat transfer to the large surface area of the piston and engine block is almost irrelevant for the end user in a well designed engine.
It is the hotspot near the exhaust valve with high EGT's that creates heat related failures.

And of course all kind of irregular combustion, such as detonation, preignition and so on.

In well designed factory engine almost impossible to melt piston unless pushing well over double power output.
The only ways are abnormal combustion and also creating an extremely intense hotspot near the exhaust valve by having very late timing.

This is true. Especially if probe is after turbo, it says absolutely nothing. Only useful for protecting catalytic converter.

Most turbochargers are rated between 950C-1050C TIP continuous. Running 1100C+ EGT with ALS will destroy the turbo.
You will also probably damage the exhaust valves because depending on timing it is possible mixture is still burning when exhaust valve opens.
There is absolutely no need for such EGT though. You can have easily ~900C EGT with turbo producing meaningful boost.

Unless CR was dropped then fuel economy should not change except when actually using the extra power.

In case of production engines in 99% cases less EGT = better.

Forgive me if this is a stupid question. I've been following this thread for years and I want to thank everyone for their effort. I've just discovered openmoose and I'm currently reading my bin file from my 2005 xc70.  I want to do some logging but where do I find or got to I create an XML parameter file?

How do I tell what code my ecu file is?  I'm hoping my 05 xc70 is GSHJ.  I guess I can try this xdf with my bin file in tunerpro

That appears to be the case. Thank you for the response!

First thing I'm going to do is change my bin file for blue injectors.  Time to learn!

If anyone has any tips on what changes to make for a 16t I'd appreciate it.  That's what I'm going to work on after getting blue injectors working.