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I don't discount what you are saying. But the issue I'm trying to get a grip on IS EGTs. EGT of sustained 1100 verses EGT of sustained 1400. The effect of additional stress non-withstanding (head gaskets), the effect on a block of aluminum (the piston) which causes it to change state (melt) is HEAT, and as far as my education and understanding goes, only HEAT. It's not exactly rocket science. /forums/images/graemlins/smile.gif
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OK I have waited to see what everyone had to say till here, now I can put a few dots on I's.
What we are talking about is Exhaust Gas Temps that means the temp coming out which could be way different from what the combustion temp is. It is only an indication that helps control the use of the engine.
EGT's could change drastically once they are out of the chamber mostly by the speed they come out (high boost pressure) which could cool down quicker (lower EGT).
Which brings me to point 2, higher pressure and same temp will create the effect of higher temp, it's been a while since I was in physics class but in laymans terms, we could have higher temps on the piston top with lower EGT's.
I hope this helps explain the reason for different EGT limits for NA vs Turbo.
Alos my GM shop manual says 1300 for NA, I will check again for numbers on the 6.5TD if I have them, maybe we can get an idea if GM had the same difference between NA and Turbo.
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