Can anyone explain to me the effect of the AC compressor on reduced engine power?
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Junior Member
Joined: Apr 2000
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Can anyone explain to me the effect of the AC compressor on reduced engine power?
I know this is true of all cars - that with the AC on, the engine's power is reduced. My question is: why? I'm pretty untechnically minded when it comes to cars, so I'm sure the reason is quite simple. I do know that the AC makes the engine work harder but why is that?
The reason I ask is that since this heat wave in New England over the past 2 weeks and with my AC running non-stop, I've noticed an enormous difference in driving my car. I've almost stalled out numerous times with my AC on because I don't even realize I'm not giving the car enough gas.
The reason I ask is that since this heat wave in New England over the past 2 weeks and with my AC running non-stop, I've noticed an enormous difference in driving my car. I've almost stalled out numerous times with my AC on because I don't even realize I'm not giving the car enough gas.
AudiWorld Super User
Joined: Mar 2000
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2 factors working against power output.....
One of them, simply, is that the AC compressor takes a certain amount of power to actually drive it. Figure about 10-15 hp in some cases. The exception here is on WOT(wide open throttle). In this case, the A/C clutch disengages until you let back off the gas.
2nd. In warm weather, all cars experience decreased HP levels, whether the A/C is running or not. I could go into all of the resons why this is, but just accept it so I don't have to type so much;-)
2nd. In warm weather, all cars experience decreased HP levels, whether the A/C is running or not. I could go into all of the resons why this is, but just accept it so I don't have to type so much;-)
Elder Member
Joined: Mar 2000
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could you please explain to everyone ALL of the reasons .. .
why in hot weather we lose power? Some of us would like to know the reason and I am sure Jake would like to add another entry into his FAQ on <a href="http://www.auditt.org">auditt.org</a>! 
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On my 200, they reduce the boost on very hot days to keep the car cooler....
I'm not sure if they do the same for the TT, but it sure would make sense. Plus, they also reduce boost if you don't drive it hard enough, to save the engine. Hope that helps.