Fuel consumption, hot weather, and the air conditioning... - PeachParts Mercedes-Benz Forum

jassz · #1 08-05-2003, 10:55 PM

For those of you that use your ac seasonally, do you find it has any impact on fuel economy? Do you get less mpg in the summer? Someone that was trying to sell me a car once (in December) told me that it got much better mileage in the summer when it was hot (I don't know if that was without AC on). But, I am using MORE fuel. About 5%, I think (sitting here trying to do math in my head!

)

If it's jsut the AC, that's okay. I'm just trying to rule out something else causing this.

Thanks!

leathermang · #2 08-05-2003, 11:26 PM

YOU are in CANADA .. roll down your windows and feel the cool air....
On a car as old and beautiful as yours you will use a little more fuel using the airconditioner...

On later cars built in wind tunnels... ( and ugly look alikes of each other ) they usually get better mileage with the windows rolled up and the ac on....

bjcsc · #3 08-06-2003, 07:09 PM

I'm using more fuel in the summer time. I get about 1 mile less per gallon which is right about 5%. I've been wondering if it was something else, too...

Rick Miley · #4 08-06-2003, 07:14 PM

Summer will be over for you in Canada next week, right?

Then you can start griping about reduced mileage because of winter blended fuel.

jassz · #5 08-06-2003, 08:45 PM

Quote:

YOU are in CANADA

GASP!!

That explains SO much! The winters. The taxes. The beer. :p Thanks leathermang, you're a wealth of knowledge!

73MB280SEL · #6 08-06-2003, 09:18 PM

jassz,

LOL, You know, you've got some mighty pretty country up there. I was in Regina Sescatuan (however you spell it) a few years back an was very impressed. This was in August mind you.

Here in OKC, we've had 100 deg F or there abouts for a month straight. It has rained maybe once. August is our hottest month, so we will have another 100 deg F month to deal so inadequetly with---ouch.

I really need to hop on that A/C upgrade project I've been tinkering with. It's been even hotter down in Texas where Greg is.

To answer your question, yeah, my mileage has been impacted quite a bit. Earlier in the year, I was nailing 40 mpg every fillup. Now, it is about 32 - 35.

I've got a R134 conversion so you can really feel the compressor hit when it turns on.

Sholin

psfred · #7 08-06-2003, 11:17 PM

The milage in all the cars drops a few percent with the AC on -- more on the big gasser (15.5 rather than 16.5). Best milage on the diesels is usually spring and fall.

Summer in Canada lasts until you put your short pants away. This can be as early as June or as late as November, depending on you cold tolerance -- the last summer I was in Sault Ste. Marie, I left the furnace on all summer, we had a frost every month that year.

Sure is pretty in a couple weeks, though!

Peter

leathermang · #8 08-06-2003, 11:44 PM

Natalie,
If you had only asked earlier.. I would have shared that information... I did not realize others had been keeping it from you...
From what I have read.. under full heat load and at speed ( which increases the loss from the hot air going over the car and expecially the windows ) an air conditioner can pull as many as 8 hp from the engine...
Then add that with over 100 degrees in some of these examples... that the air is thinner due to the heat... (thus the engine has less air stuffed into the chamber)
And I am surprised that 5% is all the drop that is manifested. I say it is well worth it for the comfort of Air Conditioning.....

"The mileage in all the cars drops a few percent with the AC on " this only applies on the new wind tunnel cars if you keep the windows rolled up.. as that is how they are built to get such good mpg in the first place....

jassz · #9 08-06-2003, 11:45 PM

Sholin, if you liked Saskatchewan (don't worry about the spelling, we just shorten it to SK

), you'd love BC. Very beautiful, at least when the sun shines

. I like Saskatchewan too though (that's actually 'home'), there is something magical about a place where the land is so flat you can watch your dog run away for two days. :p

Well, I hate to use the word 'hot' in this company, but it has been 'hot-ish' :p This is actually the hot-ishest driest summer I ever remember in BC. I guess that's why the whole damn place is on fire.

Anyway, if the increase in fuel consumption is normal, I guess I'll go find somethng else to worry about. :p

Thanks!

leathermang · #10 08-07-2003, 08:03 AM

" I hate to use the word 'hot' in this company" ... and well you should ... we think it is funny when a Canadian uses it.... it was 101-104 here in the Austin area yesterday ( and we are always muggy also).... 109 in Dallas ( actual..NOT heat index ).....the 7 day forecast is ALL in the triple digits...
We are very sorry about the fires raging in Canada and the US... a real tragedy.

Wasuchi · #11 08-07-2003, 09:26 AM

Yep, it's hot down here..... only 106 yesterday, I hate to even think what the HI (heat index) was.

R Leo · #12 08-07-2003, 10:14 AM

Quote:

..... only 106 yesterday, I hate to even think what the HI (heat index) was.

At least lately here in Central Tejas, with the wind out of the due south, it has been a DRY heat!

Hydrate or die.

jassz · #13 08-07-2003, 10:41 AM

Ouch, that IS hot. I guess you don't use metal patio furniture much, you'd get waffle-butt. :p

Once again I'm at the disadvantage of trying to convert back and forth from metric. I know 104 = 40C. It rarely gets THAT hot on the coast (anything over 32 and we get wilty

Then again, no one has airconditioning), but where we are headed (southern BC) it is not uncommon to get up to 40 (or over). Parts of it are actually a bonafide desert.

I think I would spontaneously ignite at 106.

rickg · #14 08-07-2003, 10:48 AM

Natalie, aren't you supposed to be leaving on vacation today? If so, have a great trip! (If not, never mind.:p )
We want a report when you get back on how the 'ol Benz did.

Oh, and BTW, I did notice a lot lower gas mileage on our trip than I expected. Only thing I could attribute it to was pulling alot of mountain passes with the A/C running. I usually get around 25mpg, but it dropped down to 22.5 average for the trip. Go figure.