Armchair theory - extreme cold air intake.

[djct_watt]

Originally Posted by cfeng

I'll try my best to explain this.

A turbo or supercharger system is adiabatic. It increases pressure to force more air into the engine.

The system described by beer jammer is technically another forced induction system, however instead of being adiabatic, it is isobaric, where pressure does not change since the air molecules are squeezed together by cooling.

The flaw with beer jammer's idea, which probably other people see, is that using an air conditioner as a forced induction system involves more imperfect energy transfers where energy is wasted. It employs an air conditioner which cannot surpass carnots predicted efficiency (lose about 20-30% here), then it would need some heat exchangers (20-50% loss, governed by newton's law of cooling). It would be much more efficient to use a turbo or a supercharger.

So well put, it's near impossible to add to it. But considering the HUGE inefficiencies of using an A/C, I'm fairly certain that the cooling effect would still result in a NET LOSS of power. It'd be like having a cigarette lighter powered coffee machine boil water to power a steam generator that is connected to the crankshaft.

[eTiMaGo]

Originally Posted by djct_watt

So well put, it's near impossible to add to it. But considering the HUGE inefficiencies of using an A/C, I'm fairly certain that the cooling effect would still result in a NET LOSS of power. It'd be like having a cigarette lighter powered coffee machine boil water to power a steam generator that is connected to the crankshaft.

I don't think the OP realizes just how much power the AC saps. you could try this, start the car, AC off, then start driving at part throttle in second gear, then turn on the AC and feel how much the car lurches...

But, upon thinking about this more, there is *one* way in which this idea could work. Suppose in a normal driving scenario, you are not at full throttle all the time, sometimes you are slowing down, sometimes you are just cruising at part throttle. These would be the times when the AC compressor is engaged and generating a charge cool air, but this cool air does not go into the intake, there is a valve to prevent this. But, once you go to full throttle, the AC is disconnected by the pulley clutch, the cold air valve mentioned above is opened, so you get a small charge of cooled air into the intake, And, whatever air follows is still cooled to a certain amount by the still-cold evaporator... It would be a very short-term effect, but it *could* work. I sorta experimented with the same thing in an effort to use the AC without wasting fuel, only engaging it when I am in DFCO. It works, but not very efficient :p