A/C & engine power

VolvoFreak · Post by **VolvoFreak** » 10 Jun 2005, 09:39

This is the first summer that I've had my '93 850 and have a question for you all: When the A/C is turned on, there is major power loss, maybe drag in the engine and my gas milage drops from 28mpg to the low 20's. Also, when I'm idle at a stop light/sign, the engine feels rough. Is this normal operation for an 850? When my parents had their '95, I don't recall this happening to that car. I feel I should also mention that every so often the AC/REC lights do their flash routine like others on the board, but not all the time. Maybe I'm too much of a perfectionist when it comes to my vehicle, and this is nothing to be concerned about, but I just want to make sure...

turbotim2 · Post by **turbotim2** » 13 Jun 2005, 11:36

The AC compressor defintely draws a lot of power from the engine to run, especially in small engines like these. I have defintely noticed significant power loss in mine.

Jot · Post by **Jot** » 13 Jun 2005, 13:35

Four or Five HP to run the A/C is what I have been told.

Guest · Post by **Guest** » 13 Jun 2005, 14:17

I think you'll find it is quite a bit more than 5 hp. It takes about 8 just to run a belt driven cooling fan (not FWD)

VolvoFreak · Post by **VolvoFreak** » 14 Jun 2005, 08:19

The last car that I had a (working) A/C in was an '88 Olds with a 3.8l v6. I didn't notice much of a draw at all with that car. With my 850 having a smaller engine, I take it that it will make a noticable difference?

turbotim2 · Post by **turbotim2** » 14 Jun 2005, 08:46

Mine does, I really notice it going up hills. I am thinking that at 50 mph the engine is taching about 2,000 rpm. The engine is probably making about 50-60 hp at the rpm (168 hp @ 6,000 rpm) so there isn't a whole lot of extra hp to run that compressor, especially when trying to get up a hill. Your Olds made more power at the bottom end and probably weighed less so it was less noticeable. Just my thoughts. I have V8 cars and trucks that you can't even tell the compressor has kicked on.