This might show my age but --- it seems that Im getting more mileage when I use the A/C compared to when I switch it off. I have always thought that using the A/C will use more fuel. At least in every car I had until this one I think I remember reading something on this forum a while back about the computer leaning out the fuel when the A/C is engaged ?? This would explain it, but still. maybe some of "Techies" can confirm my suspicion. If this is indeed true, at $2.36 for Mobil 93 around here that 'Full Auto Climate Control' is staying on baby !!!!

 

Well, here in southeastern CT I paid $2.399/gallon the other day at Mobil for their 93 octane. As for the A/C "saving" gas I find that hard to believe. But in any case, if I'm feeling the weather the A/C goes ON, regardless! After all, the CL-S is a semi-luxury car. I want to show up at my destination not sweating to death in lieu of saving a few nickels and dimes by having the A/C off!

 

No wind resistance with the AC on, you could just close the windows, leave the AC off, and die from the heat, leave a note telling family to sue the oil companies for not making enough oil for you to afford gas and run the AC or have the windows down.

I got 29mpg on my last tank full. I did a few WOT runs 1-3, but I was also doing 25 in 6th, so I made up for it.

 

FWIW:
http://www.cartalk.com/content/colum...94/May/05.html

 

 

right ....but how about my suspicion that the mixture leans out when the A/C compressor is running ?? I will swear I am getting more MPG while using it

 

IMO, if you are talking about fuel-air at cruising (part throttle), I don't think so.

You generally save energy with the A/C on at highway and freeway speeds. The saving is due to the lower drag with the windows closed outweighing the energy used to run the compressor and fan motors. If you are only doing 5MPH, you are going to use more energy with the A/C on.

If you switch on your A/C, you will notice a brief change in RPM at idle. If you monitored fuel flow, you would register an increase. (That includes air too.)

I have doubts about the fuel-air being leaned out with the A/C on. It's possible, and if someone wanted to prove or disprove this, they could check the exhaust's fuel-air ratio under part load.

YMMV

 

ok ericl
here's a question for you,,, is it possible to advance my timing. ie force a advance even thru the cpu is trying to match up to a saved map that might not take full advanage of the 93 octane I have around here.

 

I have always seen worse gas milage with the AC on. No matter what car I was in. Of course my car is set to 70 10 months of the year.

 

AS of the moment, I don't think so.

However, I think someone is coming out with a piggyback chip, and you might want to ask Scalbert if it will allow you to alter the ignition timing tables.

And...

Even though Acura says the car only requires 91 octane, I never heard them say that the car will not take advantage of a bit more octane. When I was mixing varying amounts of 100-octane, 76-unleaded gas to our California-crummy 91 octane, I was getting better acceleration using 93 octane and above. I didn't find any improvement of note above 93 octane. And, I must caution that the gains might have been realized from the different fractions in the 100-octane gas. I did the tests using a Gtech and repeated the tests over a year period. I did the tests when the temp was in the 60- to 70-degree range, and always used the same road.

So, are you sure you are not getting the advantage of the 93 you are using? Would it hurt to add in some regular to move your octane down to 91? And, then you could be your own test master.

 

If you are doing most of your driving around town, and do a fair amount of idling, I'm not suprised.

So, your compressor is running almost all the time, and if you aren't "cruising" at highway speeds, the energy needed to run the compressor is going to be greater than the energy needed to overcome the turbulence-induced drag that comes from windows and/or sunroof being open.

Try A/C on + windows/sunroof closed vs. A/C off + windows/sunroof open at a test track at 100-MPH, and call us back. See if you still get the same results.

It goes without saying that depending on driving style, everyone is going to have different experiences.

Finally, don’t forget that at higher temps, when someone will probably be using A/C, the air has less density and the car will cut through the air easier. If you run at high speed, with the A/C off, and the air is cold, the car is going to see more drag with the denser air. Once again, this difference would have to measured under controlled conditions and a large difference in ambient temperature combined with high speed and a flat road, would help demonstrate any differences…

YMMV

 

I always drive with the windows down no matter what the temps, hot or cold. However today it was raining and kinda hot outside so for the first time since i got the car about 14 months ago i fired up the A/C.

Overrated IMO.

 

I run A/C all the time. Too much traffic to not use it. I just ride the motorcycle when I have the windows down craving.

I have no technical or factual information, but I really think A/C on or off does not make much difference in gas mileage in the CLS.