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Old 08-20-2014, 05:46 PM   #40 (permalink)
Mitco39
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Quote:
Originally Posted by 1slow370 View Post
Mitco, while a plenum IAT sensor isn't very important as far as calculating fuel demand and air mass goes if you have the one in the MAF, timing and temp corrections for burn speed and injection angle are going to be effected greatly if there is an unmetered increase in air charge temperature.
While I agree with you on basis I would argue that real world adjustments to the fact would cause very little if at all 0 changes to the overall output of the engine since we are not dealing with direct injection engines. That argument would be valid if we were talking about emission generation and controlling the hydrocarbons. But usually when one is concerned about that it is during a constant state operation such as idling or cruising down the interstate.

On a direct injected engine that does not rely on the fuel evaporating (and thus cooling the charge before it hits the engine) I would say that yes it becomes a greater concern, in fact all the diesels I tune have a IAT right before the air hits the plenum for that exact reason. The IATs have a large effect on the burn rates in direct injected engines because you do not have the cooling evaporation effect before the air enters the combustion chamber.

Again its just my opinion on the matter. Plus if you look at the Uprev timing tables there is only so much fine adjustment available to the end tuner. Its a limitation to the memory in the ECU.
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Last edited by Mitco39; 08-20-2014 at 05:49 PM.
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