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Power Loss with A/C On

ChevyHDGert

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ChevyHDGert Enthusiast

ChevyHDGert

Posted
Posted

How much power loss is typical with the A/C on?

 

I've got the 6.0L and the power loss is very noticeable. I know I should expect some but I'm just wondering how much is too much?

citydriver Enthusiast

citydriver

Posted
Posted

Join the club..I know I only have a '95 w/a 5.7L but it gets down right DOGGY off of the line when the A/C is on...I think between the compressor and the alternater,it ROBS almost 20 horses,at least thats what it feels like :rolleyes:

SteveCZ Enthusiast

SteveCZ

Posted
Posted

:rolleyes:

 

Same here..... gotta really wind her up to get her goin with the A/C on

 

One good thing about the A/C is its meat locker cold though!!!

OUMike Senior Enthusiast

OUMike

Posted
Posted

Hmm....granted I have a 94' 4.3L, I don't really notice any power loss. My mileage is a little different, but not much. My AC usually effects mileage by about .5-.9 mpg. Maybe my truck is just extra efficient??

GONZO Enthusiast

GONZO

Posted
Posted

you have a 6.0L and can tell a differance in power when the ac is on?!

 

i would say something is wrong, my 6.0L doesn't change a bit power wise when ac is on. it will use slightly more gas when ac is on... maybe .5 mpg. my truck pulls right at the gcvwr with ac on... still has plenty of power.

 

 

the only cars i've "noticed" when the ac was on is usually 4cyl cars that are already under powered to beging with.

robsawatsky Enthusiast

robsawatsky

Posted
Posted

I've got a 5.7 in my 2000 pickup and I can hear (sometimes) when the compressor comes on but haven't noticed any power difference. Very unlike the 97 Plymouth Grand Voyager with 3.0 that loses considerable acceleration with the AC on.

Xao Enthusiast

Xao

Posted
Posted

I have to say that I have not noticed any power loss with my '04 with a 5.3.

 

I hear the compressor turn on and I can vouch like the others that the gas mileage takes a small hit.

 

Now, I haven't towed a load with the air yet, so maybe that makes a difference...

JamesB Enthusiast

JamesB

Posted
Posted

With my '02 Z71 5.3 w/ 3.73s, I don't even notice a difference with the A/C on. Towing or not... However, My '91 Suburban with a 350 was a dog with the A/C on...

 

James.

Wingnut Senior Enthusiast

Wingnut

Posted
Posted

Neither of mine have hardly any power loss with the AC.

 

I won't lie and say that there isn't one, it just isn't all that noticeable.

 

5.3 in the 02.

5.7 in 92.

  • 2 weeks later...
Supurban Enthusiast

Supurban

Posted
Posted

In my 04 5.3L Sub it is barely noticable that the AC is running. An easy way to exaggerate the lag is to turn on the compressor as you are accelerating up a highway ramp. While I haven't towed with this vehicle, I would turn off the AC anyway on hills and the like. On hot, hard tows, I actually used to run my heater (as an auxilliary radiator) with the windows down while towing two Sea-Doos behind my 2.2L Subaru Legacy just to be sure! :seeya:

az'03Silverado Senior Enthusiast

az'03Silverado

Posted
Posted

Come on down to AZ in the summer when it's a good 110+. I have the A/C on plus every time I stop the cooling fan clutch kicks in. Feels downright gutless. Sounds cool though sucking all of that air through the radiator. :rolleyes:

Import Hater Enthusiast

Import Hater

Posted
Posted

Well....technically, no power is lost. If you try to measure max power on a dyno or your nearest on ramp, you'd be at wide open throttle right? As far as I know, modern vehicles have a logic in their PCMs to disengage the A/C clutch at WOT to make sure the A/C doesn't steal any power.

 

Just cruising along though, the drain varies based on A/C system pressure/oil levels, compressor efficiency, and ambient temp. I wouldn't be surprised if it's as high as 20hp on some vehicles. I remember a funny bit of creative writing in one of the car mags a while back referring to driving a puny little 4 banger econobox. "Turning off the A/C was like turning on a supercharger."

 

Rob

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