Cold affecting gas mileage?

[Ibi]

i filled up on the weekend with 91 from Petro. i usually average 450/tank all city before i fill up. right now i've done 300km all city and the fuel warning on the navi came up saying i've got 70km to go before it runs out. (i've been very easy on the pedal..)

thats about 100km difference, so im just curious. i've had the the heat on, but does it affect it this much? (i've had the AC running all summer and the mileage was just fine.) or maybe just bad gas?

any thoughts?

[bimmerfile]

OP;
Do you generally get your fuel from Petro? I believe they have ethanol in their 91 fuel.
Try Shell V-Power 91 - it's ethanol free and you'll get better mileage.

[Dackelone]

Ethanol winter blend is my best bet. I would look for another gas station.

[vanbmw]

Air conditioning is harder on gas consumption then heat. Your a/c requires lots of energy to power/turn the compressor and robs the engine of power. Your engine is always producing heat as a byproduct. It does require some energy to power the blower in your heater but that is really it. I would not think that is the sourse of the bad mileage.

[Kcc]

Winter does use more fuel, but I don't think the different would be 70km unless there is snow. But 450km a tank regularly is a pretty good number to me. I can only get 400km max soft on the pedal in all city condition.

Kcc

[Ibi]

im thinking it was just shitty gas. i'll ride it out then fill up with shell on the way back from work.

[The1]

you're a victim of the winter blended gas. there are 8 different blends for the companies (at least in canada) which is 2 blends per season. when it gets really cold like this, or it's forcasted too, the stations dump a whole bunch of different fuel treatments in their fuels and the grade of fuel itself is lower to prevent the gas from getting too sludgy and causing extra carbon buildup in the engines.

this is to the benefit of your car to run these fuels, but not a benefit to our wallets.

if you've ever seen diesel fuel cold, you'll understand. it basically turns to molasses (regualr gas isn't nearly this extreme)

this is also why most car companies recommend a thinner oil in the winter so that it pumps easier at warm up.

and another thing.... check your tire pressure, now that the air is cooler, i guearantee your tire pressure has dropped a few PSI this affects fuel consumption a lot as well.

[Kcc]

"The1" nice info, but what do you mean by "companies recommend a thinner oil in winter"? Do you mean the engine oil?

Kcc

[The1]

yes, thinner oil helps at startup as it doesn't take as long to get thinner and flow better. summer oil is more syropy, so when it gets really cold, it barely flows at first, which is not good for the engine.

That being said, it isn't as common as it was a few years ago. oil additives and technology are making them slightly more universal.

or in BMWs case, they think it's unnecessary because they don't want to pay for the extra oil change.

[The1]

Random quick explanation

I just found this for you to look at. obviously depending where you live and such, it's mostly just a reference....

I ran a 15w50 in a turbo motor i once had... my car loved it in the summer time.

[dtwyim]

The1, any comment on Esso gas?
Thx

[The1]

unfortunately, i'm not to familiar with running esso, I've run a series of tuned cars and have either run shell or sunoco/petro 94

however, as ESSO is a teir 1 company, it will have a lot of the same/similar and necessary fuel scrubbers as Shell, Sunoco/Petro.

So if it helps, Esso should be an ok brand to stick with, just don't go to "mom & pop" gas stations to fill up.

Also, if you pull into a gas station that has the gas truck there, turn around and go to another station. When the gas delivery truck delivers fuel, it stirs the tanks up and the sediment on the bottom can be transfered into your gas tank.

this will result in a clogged fuel filter much sooner then normal. Also resulting on more wear and tear on fuel pumps.

[EA51 LAY]

Esso in my experience isn't that great - in my old 135i cab (running JB 2.0 upgrade) or in my M3 sedan. Its more noticable in the turbo set up - but I would go Shell only from now on! Petro Canada seems dump too (Sunoco 94 or not).

BMW Customers here seems to be in agreement too!

[Raine]

Yeah I only fill up w/ Shell 91 now, also my mileage has been getting worse because of the cold =(