Quote:
Originally Posted by 9phil9
When the ECU is correcting for air/fuel ratio and the incoming air is cooler, it simply adjusts to a ratio that maintains the correct set ratio.
The benefit of a cold air intake is increased HP, because the engine can take in more air, and thus, more fuel, at the same rpm.
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And why is the engine using more fuel? Because the engineers know that colder air is denser, and intake temperature is figured into the fuel maps, hence why the increase in horsepower during the winter or on cold days. If the AFRs were static based on arbitrary values, we'd see serious reliability issues during temperature extremes such as those in the North during the winter and those in the Southwest deserts during the summer. The loss of power on hot summer days is directly related to the density of the air. The ECU is programmed with
variable fuel maps dependent on intake air temperature (and other things, such as coolant temperature, engine load, VVT-i, etc.) because air density is based on that temperature, thus, if the intake air is hotter, the ECU will scale back the fuel because there is less air entering the cylinders at any given RPM in comparison to cold air. If the ECU did not reduce the amount of fuel, the engine would run quite rich and possibly fail emissions, in addition to wasting unnecessary fuel.
Engineers use cold air intakes to provide the best possible engine performance, not necessarily efficiency.
So, how about you remove your head from out of your *** and read up on fuel management on modern day electronic fuel injected engines?
There is such a thing as cold start enrichment.
There is also such a thing as engine enleanment during off-throttle operation.
So ... you pretty much proved my point. It doesn't take a genius to understand that in order for the engine to keep its set AFRs, more or less fuel must be used in relation to the density of the air and inputs from other sensors. Hot air is less dense, hence in order to maintain a stoich fuel mixture, less fuel is needed
relative to colder air.