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Originally Posted by libbybapa
Yes the probe was immediately after the turbocharger and so add 250°F for a pre-turbine measurement of 1150°F.
Therefore, advanced injection timing results in both elevated peak combustion chamber temps and lowered EGT's. A very frightening combo. Go ahead, give it a try and report back your results. How about 30° BTDC? Or if you don't have as much belief in your argument that advanced timing does not lower EGT's while raising peak combustion temps, then retard your timing to 15° BTDC and check out the EGT gauge. I am quite sure you'll see it elevated.
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The position of the probe now begins to make some sense. The temperatures at the ports could have been well on there way to 1200°F. The damage to more than one piston also answers some additional questions.
I fully agree that retarded timing will cause increased EGT's, but the concept of reduced EGT's due to advanced timing remains difficult to grasp. If the combustion temperatures are higher.......for all the reasons mentioned.......the exhaust temperatures at the exhaust ports should also be higher. I simply can't envision a the scenario where an elevated combustion temperature can dispose of all that excess heat into the cooling system in a very short period of time and result in a lower exhaust temperature.
However, I've never tested it.......so........I reserve the right to be wrong.
