AC noticeable drag on engine
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Joined: Aug 2005
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From: Canada
E350 4Matic 2011
AC noticeable drag on engine
Does anyone notice that one very hot days when their AC is running there is a noticeable drag on the engine and when standing beside the car, it is very loud ? Didn't have any of this on my old E.
Mine is a 3.5 2011 and I wouldn't expect the AC load to be noticeable when driving given the engine power.
Mine is a 3.5 2011 and I wouldn't expect the AC load to be noticeable when driving given the engine power.
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From: New Mexico
2014 E350, 2012 SL550
Does anyone notice that one very hot days when their AC is running there is a noticeable drag on the engine and when standing beside the car, it is very loud ? Didn't have any of this on my old E.
Mine is a 3.5 2011 and I wouldn't expect the AC load to be noticeable when driving given the engine power.
Mine is a 3.5 2011 and I wouldn't expect the AC load to be noticeable when driving given the engine power.
If you're outside the car it is normal on any car to be able to hear the A/C cycle on and off and hear an apparent short drag on the engine. And, yes, the A/C can be quite loud from outside.
Regards,
Don
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From: Canada
E350 4Matic 2011
Thanks for the reply. I even notice the difference at the gas pedal. I actually have to push down more to get the car going when the A/C is on. It is as if the brakes are partially on!
Hmmm... time for a check up at the dealer.
Hmmm... time for a check up at the dealer.
Thread Starter
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Joined: Aug 2005
Posts: 216
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From: Canada
E350 4Matic 2011
Found another thread discussing this topic.
https://mbworld.org/forums/s-class-w...s-c-being.html
The loss should not be noticeable.
https://mbworld.org/forums/s-class-w...s-c-being.html
The loss should not be noticeable.
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Tesla Model S P100D
Great find! Thanks for posting. SO apparently only about 5-10 hp and less than 10 torque. Good to know. So my habit of turning off the AC to get maximum power on rare occasions is apparently meaningless. Good to know.
I bet you loose more power by rolling down the windows than turning on the AC.
I bet you loose more power by rolling down the windows than turning on the AC.
Found another thread discussing this topic.
https://mbworld.org/forums/s-class-w...s-c-being.html
The loss should not be noticeable.
https://mbworld.org/forums/s-class-w...s-c-being.html
The loss should not be noticeable.
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Joined: Feb 2010
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2015 GL450
Great find! Thanks for posting. SO apparently only about 5-10 hp and less than 10 torque. Good to know. So my habit of turning off the AC to get maximum power on rare occasions is apparently meaningless. Good to know.
I bet you loose more power by rolling down the windows than turning on the AC.
I bet you loose more power by rolling down the windows than turning on the AC.
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From: North Scottsdale, AZ
'71 Pinto
I don't know about the E class specifically, but at least three cars (Porsche, Toyota, and Subaru) I owned were designed to automatically shut off the AC compressor briefly with high demand on the engine. With the Subaru, it was very noticeable when the AC compressor would turn off - it was also very noticeable when it would turn on.
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Out Of Control!!
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From: Earth
Porsche Macan S SportDesign / Ex M-B's: 11 & 10 & 06 E350's, 02 S500
I don't notice any difference to power output/performance with the A/C on. I even don't notice any MPG decrease with it on.... in fact, my best MPG's have happened with A/C on, as odd as that sounds.
Thread Starter
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From: Canada
E350 4Matic 2011
My issue is only at speeds less than 25 mph. At normal driving speeds, no noticeable drag and the mileage does not seem to take a hit. At low speeds on very hot days it feels like I'm driving through mud. Weird.
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From: Southern US
2010 E550, 273 Engine: 2012 S550, 278 Engine
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S350 BT 4MATIC
Hmm, with the larger engine the AC should have less effect than it will on a E350? I might get a 1 - 2 mpg diff, depending on how long I maintain a steady speed. If I have a lot of instances where accelerate and decelerate (SP?), I will notice a drop in mpg, steady speed almost no drop in what I get at speed.
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From: Southern US
2010 E550, 273 Engine: 2012 S550, 278 Engine
Hmm, with the larger engine the AC should have less effect than it will on a E350? I might get a 1 - 2 mpg diff, depending on how long I maintain a steady speed. If I have a lot of instances where accelerate and decelerate (SP?), I will notice a drop in mpg, steady speed almost no drop in what I get at speed.
Engine size should have nothing to do with how much MPG you lose with A/C on. Turning the compressor at a given speed takes the same amount of energy regardless of how big the engine is that turns it.
I have tested for this many times and it seems 2.5 MPG is what I lose at 75 MPH speed, at least this is what the car computer shows.
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S350 BT 4MATIC
Engine size should have nothing to do with how much MPG you lose with A/C on. Turning the compressor at a given speed takes the same amount of energy regardless of how big the engine is that turns it.
I have tested for this many times and it seems 2.5 MPG is what I lose at 75 MPH speed, at least this is what the car computer shows.
I have tested for this many times and it seems 2.5 MPG is what I lose at 75 MPH speed, at least this is what the car computer shows.
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Joined: Apr 2007
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From: New Mexico
2014 E350, 2012 SL550
Actually, a larger engine should be capable of handling more due to its additional HP and torque. A 4 banger wold suck eggs big time with the units on the E550. They hopefully size the compressor units to the engine, otherwise if they used the same compressor on all, you would notice much larger mpg decreases as the engine size and associated HP varies.
Regards,
Don
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2010 E550, 273 Engine: 2012 S550, 278 Engine
Actually, a larger engine should be capable of handling more due to its additional HP and torque. A 4 banger wold suck eggs big time with the units on the E550. They hopefully size the compressor units to the engine, otherwise if they used the same compressor on all, you would notice much larger mpg decreases as the engine size and associated HP varies.
Again, turning the A/C compressor at a given speed takes the exact same amount of energy regardless of the size of the engine that runs it.
If there are differences in the amount of MPG you loose for the A/C then it is related to differencies between the A/C compressors and/or the charge level of the system.
