WTF does Max A/C do?

[Homeslice]

I've heard people say that the only thing Max A/C does is simply operate the flap which shuts off outside air, so that air inside the car gets cold faster. But if that's all it does, then why does the fan speed increase as well?

[Dave]

Might be an aux fan that guides the recirc air to the inlet

[Homeslice]

Originally Posted by Dave

Might be an aux fan that guides the recirc air to the inlet

Hmm......I thought there was only one fan (usually on the firewall near the wiper motor)

[Particle Man]

I always thought it was because of different pressure in the car once the air is being recirculated making the fan blades go faster.

[Rider]

None of my cars have that. Auto climate control FTW.

[Homeslice]

Originally Posted by Rider

None of my cars have that. Auto climate control FTW.

Several cars, like the Ford Fusion, have both automatic climate control and a max A/C setting.

[Particle Man]

Originally Posted by Rider

None of my cars have that. Auto climate control FTW.

It may not be labled "MAX A/C" but if there's a button that recirculates the air you're doing the same thing.

[goof2]

Originally Posted by Homeslice

I've heard people say that the only thing Max A/C does is simply operate the flap which shuts off outside air, so that air inside the car gets cold faster. But if that's all it does, then why does the fan speed increase as well?

My guess, and it may be what Particle man meant as well, is when the A/C is set to get fresh air it is putting new air in the car. The old air has to be forced out somewhere creating higher pressure in the cabin. The fan runs slower because it has to overcome that pressure differential to get the new air in the cabin. When set on recirc it is drawing air from the cabin, cooling it, then replacing it back in the cabin. The fan does not have to work against the increased cabin pressure, its job is easier, and as a result it can run faster. I know in my truck when the A/C is set to get outside air its output increases if I crack the window open.

[Particle Man]

Originally Posted by goof2

My guess, and it may be what Particle man meant as well, is when the A/C is set to get fresh air it is putting new air in the car. The old air has to be forced out somewhere creating higher pressure in the cabin. The fan runs slower because it has to overcome that pressure differential to get the new air in the cabin. When set on recirc it is drawing air from the cabin, cooling it, then replacing it back in the cabin. The fan does not have to work against the increased cabin pressure, its job is easier, and as a result it can run faster. I know in my truck when the A/C is set to get outside air its output increases if I crack the window open.

you said it a helluva lot better than I did

[Sean]

it turns the recirc on.