GasSavers_RoadWarrior |
05-30-2008 04:41 AM |
It's theoretically more thermodynamically efficient to use warm air. There's less of the energy in the gasoline going into heating the charge, and more going into expanding and making cylinder pressure. Also due to more volume of warm air being required for a given power level, it should reduce pumping losses slightly.
The reason one can use cold air setups for more power, is that you can get more air molecules in there, for an increase in volumetric efficiency, but not necessarily thermodynamic efficiency. Getting mileage gains with cold air setups is more related to "putting one over on" the ECU and managing to run slightly leaner. Can make more torque also due to great mass of air per unit volume having more momentum.
Which works best on a given engine is all down to how fuel is metered and how accurate it is. Vane airflow systems and carbs probably fare better on hot air, MAP systems can go either way, depending on where and if intake temperature is measured (Some just guess it from CTS) MAF seem happier with cold air.
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