Afr ...

So I'm curious of parameters, with the lbo. How are these guided or rather what are the desired mixes as every engine is different etc twin turbo , supercharged turbo set ups etc

Is there a rule of thumb to say 1.01 is too low and u will melt pistons or its a guide to stay 1.2 etc .. because as u lower your lmbo you end up more power but not safely correct ? So it's better to pull it back a little to keep afr mid range ?

There is no specific rule for what mixture will lead to engine damage. Every engine is different.

The fuel mixture ratio, either calculated or measured by a lambda sensor is just one reading you can use to determine what has occured in the combustion chamber.

Exhaust temperature is another critical measurement which is an indicator of what the temperature was inside the combustion chamber.

This is all relative to how long the engine operated under these conditions and what the indended use case is.

A diesel engine being used for drag racing might operate at mixtures richer than lambda 1 but this would likely lead to excessive black smoke and is really only suitable for short periods trying to achieve peak power.

A less efficient combustion chamber design/injector design would lead to a diesel engine generating more black smoke at a leaner measured lambda than a more efficient engine. This efficiency is also related to how the heat will affect the pistons/valves etc under sustained load.

Temperature in the combustion chamber and how long the temperature is elevated for is the key factor here.

The fuel being burned is what generates the heat so yes a richer mixture will lead to increased heat but every engine will have different requirements and limitations for what is considered a safe fuel mixture to operate at.