drbf

Just another thread USCHANDPOD.

ronmart

I never use the ECO button - I simply turn it off when the top is down and the temp outside is good. If it is too hot or cold then I leave it on when the top is down, and it is always on when the top is up.

FWIW, I heard on the news that Edmunds.com just did a test and found that turning off the A/C made virtually no difference to fuel economy.I think this is the article:

http://www.edmunds.com/fueleconomy/index.html

boolala

The eco button disables the compressor. If it's below about 60 deg then you don't want the compressor on as it may be damaged running at "low" temps. If the car interior is hot (sitting in the sun) and it's "cold" out then I push the eco button to deactivate the compressor.

ronmart

This isn't an issue on the 997 (and most German cars these days) as they'll cut the compressor off automatically below 60 (or is it 50?). Try it next time it is below that temp turn your fan up all of the way and you'll notice hot air blowing out.

My Mercedes has a 1998 implementation of this and it isn't as good as I'd like because it ends up roasting me when the temp drops below 60.

Cogito

Jeff, I pressed the ECO button so that it lit up, ran it that way all Winter.
Does that answer your question?

MJones

The A/C also acts as a dehumidifier...
Thats why the interior of the windows stay clear of fog on a cold and rainy night.
even tho the heat is on,
the a/c is removing the moisture in the cabin.

We all have seen the cars with the windows fogged up .

OCBen

As long as there is refrigerant in your system, running the compressor will not harm it regardless of ambient temperature. In fact, running the compressor periodically is recommended as the valves and seals depend on the lubricants in the refrigerant for lubrication.

A typical A/C system removes humidity as it chills the air and then heats this dry cold air to "room temperature" comfort levels devoid of the moisture in order to maintain low humidity levels that won't fog up your windows in your cabin.

Buzz911S

I don't see how the compressor could be engaged and not cost you horsepower and fuel mileage.
I'm in FL, so it's in the 90's here during the day. Good place to own a white or silver car. So, I bought a new BLACK 997! I've been running around on "econ" sweating, trying to save a little gas. Premium here is $3.22/gal. So, am I hearing correctly that I can let the A/C stay on and it won't cost me power, more gas, or damage the compressor at, like... 7800 rpm? Have I been sweating for no reason?

OCBen

Don't know where you heard that but it's incorrect.

Any accessory load on the engine, be it ever so small, bleeds away horsepower and increases fuel consumption - it's an inescapable physical reality. Every car enthusiast should know that.

Incidentally, those young kids with the monster megawatt audio systems, they may be scratching their heads wondering why their newly equipped cars now get such poor gas mileage. It takes power to power those things and that power has to come from somewhere. In this case it's from the overworked alternator that has to constantly run in order to feed the power demands of these audio systems. I wouldn't be surprised if these guys go through alternators as often as batteries.

Cogito

..... and hearing aids one day soon Ben.
You know, might not be bad stock to look at, hearing aid companies, especially with all the iPods out there too.

Coochas

Yes, On is Off,,,So if the light is On, it is Off.
I originally thought the ECO switch was only for the rear seat controls until I couldn't find the corresponding "1st Class" button for my seat.

OCBen

Also, running the car with Daytime Running Lamps consumes more fuel, as any and all electrical consumption forces the alternator to come online more often, loading the engine more often.

For those thinking ahead, yes, the corollary is that night time driving consumes more fuel than daytime driving, all things being equal otherwise, however negligible the amount might be.

Buzz911S

It's posted in this thread.

I definiately disagree with this. If you want to kick the throttle hard, and your A/C is on, hit the "Econ" button and it will light up and disengage the compressor. I'm with Ben. Anything that puts any sort of drag on the engine is robbing you of horsepower and gas mileage. It's always been that way. My race car has NO belts on it of any kind. Electric water pump, no alternator, electric fan... nothing. Everything is electric and without an alternator it doesn't kill any power. Even that little resonator box that makes you hear what you think is exhaust noise inside the car robs power. That beautiful howl is not coming from your exhausts. It's artificially made by the resonator box. You can make it louder inside by capping off the air flow on the resonator box.

Those clever Germans!

OCBen

Hey Buzz, I didn't realize your first post was said in sarcasm. ... It went "whooooop" right over my head.
Now that I've re-read it, it's actually funny now that I can pick up on your sense of humor.

Sounds like your race car is a quarter-miler. A funny car?

tgibson1

Drove the car for the first time today with A/C off. It's like a different car.