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Discussion Starter · #1 ·
I've always wondered... does changing the ignition timing actually affect the temperatures inside the motor, or does it only affect what your egt gauge reads because of the delayed combustion? I can make my egt gauge read anywhere from 1525 to 1775 F depending how much I retard the timing.

-Paul
 
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Discussion Starter · #3 ·
Well, that wasn't competely related to what I was talking about, but it was a good article and cleared some things up. Thanks.
 

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DitchByTheSideOfTheRoad
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485 Posts
I agree, notice my question in the begining did cover that though :) From what I understand, and please feel free to correct me if I am wrong.

As ignition timing is pulled, less and less of the last phases of the combustion process is used to drive the piston down, and instead this energy is turned into heat. The energy exists the engine via the exhaust manifold. If less of this energy is being used for work, then more of it is turned into heat, thus raising EGT's.

"Most of your energy (in the form of hot expanding gas) is not used to propell the piston down the cylinder but rather partially propells the piston down the cylinder and the rest goes out the exhaust valves as the gas is still expanding at the end of the power stroke and has begun the upswing of its exhaust stroke. Hence some of your air/fuel burning is taking place in the exhaust manifold where your EGT probe is rather then inside your engine."
 
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