WTF does Max A/C do?

[Particle Man]

Originally Posted by 101lifts2

Yes, that is because he doesn't know wtf he is talking about.

Max A/C is for cabin air recirculation only. Notice when you have a Recirc button, you don't have a Max A/C setting. When you have a Max A/C setting, you don't have a recirc button.

Most compressors nowadays don't cycle anyway. They are either ON or OFF. The pressure control is done with valving in the compressor itself. This is not to say that the engine controller cannot turn OFF the compressore if the high side pressure becomes too high or too low or if you in a W.O.T. scenario.

My Kia has both a max and a recirc setting. I can recircate the air on every setting. When "Max" is selected, I can't override the recirculate feature.

The Subaru only has the recirc button and no "Max" setting.

[Homeslice]

Originally Posted by Particle Man

The manuals for my Grand Prix, Achieva, Explorer, and Mountaineer (not sure about the Kia or the Subaru I'll have to check) all said crack the window slightly for the first few minutes of operation to allow the MAX A/C to push the hot air out and then close the windows to allow the system to dehumidify the air and recirculate. It doesn't say "windows down" (nor did I say that).

I don't know if it's right or not (and I honestly don't care )

If your objective is to "push" hot air out the window, you'd be better served by using the Normal setting, since it pressurizes the cabin because it's drawing in outside air. On the Max setting your cabin air isn't pressurized, therefore you're not pushing as much air out the window as you could with Normal.

[Rangerscott]

Originally Posted by Particle Man

My Kia has both a max and a recirc setting. I can recircate the air on every setting. When "Max" is selected, I can't override the recirculate feature.

The Subaru only has the recirc button and no "Max" setting.

Same with our work '04 F-150. The only thing is max a/c just blows through the top vents. I always have it set to top/bottom and hit the recurculate button.

[Particle Man]

Originally Posted by Homeslice

If your objective is to "push" hot air out the window, you'd be better served by using the Normal setting, since it pressurizes the cabin because it's drawing in outside air. On the Max setting your cabin air isn't pressurized, therefore you're not pushing as much air out the window as you could with Normal.

"my" objective isn't shit. I said that's what the manual said, not what I believe.

You are wasting energy trying to convince me of something when no such action is needed. Your energy is better spend making fun of people who call the fire department when they lock themselves out of their houses or people who drive sports cars with automatic transmissions.

Kthxbye

[azoomm]

Originally Posted by 101lifts2

Yes, that is because he doesn't know wtf he is talking about.

Max A/C is for cabin air recirculation only. Notice when you have a Recirc button, you don't have a Max A/C setting. When you have a Max A/C setting, you don't have a recirc button.

Most compressors nowadays don't cycle anyway. They are either ON or OFF. The pressure control is done with valving in the compressor itself. This is not to say that the engine controller cannot turn OFF the compressore if the high side pressure becomes too high or too low or if you in a W.O.T. scenario.

I have both MAX and re-circ on my 1-Series. Actually, I have MAX and three settings to recirculate air. If I select MAX it drops the selected temp to 60 and does a full lockout to recirculate the air. The MAX selection also locks out the passenger's ability to select their own temp. I'm still trying to figure out the three settings on re-circulation. I might have to RTFM

[fasternyou929]

Originally Posted by 101lifts2

Yes, that is because he doesn't know wtf he is talking about.

Max A/C is for cabin air recirculation only. Notice when you have a Recirc button, you don't have a Max A/C setting. When you have a Max A/C setting, you don't have a recirc button.

I couldn't have come up with a better rebuttal. Thanks for talking out your ass and saving me the time.

[101lifts2]

Originally Posted by fasternyou929

I couldn't have come up with a better rebuttal. Thanks for talking out your ass and saving me the time.

Dude I'm a service engineer for a car company...and have worked with car companies since I was 22. If I know anything in this world...it's cars. You guys just guess at shit...or try to analize things using general common sense. Your original statement that the compressor cycles because of "Max A/C" or "Normal" just is not true.

Those that have Max AC and a Recirc button is simply for air venting direction (Max AC) and then % outside air using the Recirc button.

[101lifts2]

Originally Posted by Homeslice

If your objective is to "push" hot air out the window, you'd be better served by using the Normal setting, since it pressurizes the cabin because it's drawing in outside air. On the Max setting your cabin air isn't pressurized, therefore you're not pushing as much air out the window as you could with Normal.

The inside cabin is in no way "air tight" in any vehicle and you are always drawing in at least 10% outside air on the recirc button.

If you want to cool the cabin quickest and it's hot outside, you use the recirc function. This will make the differential temperature across the evaporator the lowest.

[Homeslice]

Originally Posted by 101lifts2

If you want to cool the cabin quickest and it's hot outside, you use the recirc function. This will make the differential temperature across the evaporator the lowest.

Again, what if the interior temp is hotter than the outside temp?

[101lifts2]

Originally Posted by Homeslice

Again, what if the interior temp is hotter than the outside temp?

And it probably is initially...but put in on Recirc. and 10 seconds later the temp will be less then the outside air temp.