does anyone know if there is a difference in power with putting it on full blast "4" or low like "1". what im saying is does "4" rob more power than "1" with the a/c on? also, what about just a/c and max a/c?

 

running the AC period will put more stress on your car...period. It's the compressor that causes this drag...fan speed is irrelevant...

 

so if the a/c is on it'll rob the same amount of power no matter what. and waht about the difference between a/c and max a/c

 

Read what Kronik said. Running the A/C uses the compressor.

 

There wouldn't be much difference on power output -- unless of course you're counting the airflow through your cabin haha!

 

MAX just recirculates the cabin air rather than bringing in fresh.

Dave

 

MAX A/c is colder because it is recirculating and cooling the already-cold air, and it seems that your system would work more efficiently on MAX since it doesnt have to cool off 90 degree humid air (like here in MD).

 

How noticable of a difference in power results from running the compressor????

 

Some one did a dyno test on a stock evo with the A/C on and off. It lost about 20% power with the A/C on. The fan speed and compressor or totally different, the A/C compressor is either on or off, the fan has the different speeds.

 

I've been wondering if the compressor will run more often with the fan speed turned up. From what I can tell (at idle; a/c + fan on at different speeds) it doesn't seem to matter; compressor kicks in at regular intervals despite fan speed.

So I'd go with "no" on whether or not the fan speed affects how 'hard' the a/c system is working.

 

i don't know why... whenever i have my AC on full and inside my car is freezing... my car feels faster :P guess cold air= power ?

 

That's the craziest thing I've ever heard. You sure you know what your car feels like without the a/c on? I know people who never drive with it OFF.

edit: I take that back; lots of crazier things said on this forum.

 

yes i know it sounds crazy.. i thought it should put alot of drag on the car... i didnt start my own thread about this cause people might think im crazy.. when its hot..my evo feel alot slower.. then after i have the AC on full for a while... it does feel alot faster... my voltage reading isnt going down by a bit neither... i guess it could be the Hyper voltage system and grounding system...

 

Well heat is a major power killer with these cars for sure. I cannot imagine that running the a/c would make it faster though; it's counter intuitive since the engine is under more load. Maybe compared to the non-a/c + heat power, the FAN ON + a/c + heat power seems to be more?

 

They must have had a standalone ECU, then. The stock Evo ECU has a feature build into it that works like this, from what I understand:

If the AC is on and you go full throttle, it kills the AC compressor at 5,000 or 5,500 RPMs (I can't remember which it is). The AC compressor doesn't turn back on again until the RPMs fall under that same specified speed for more than 5 straight seconds while the throttle is less than a certain throttle percentage (to compensate for gear shifts while accelerating).


The 4G63 powered 2nd Gen DSM's had a throttle percentage AC compressor disengagement, but it wasn't relevant to the engine speed. Technomotive used to do EPROM burns to enable this feature on the DSM's, since the ECU has control of the compressor clutch relay.