Average MPG Dropping

[johnny51981]

Ok, first of all, my Average MPG only reached up to 45.4 in the almost 8 months that I have owned it. I'm satisfied with it since it is much better than my 20 MPG Blazer that I owned prior to.

Now that we have had the time change and the colder weather, it has dropped almost a mile. I understand since I'm using the headlights now, using the windshield wipers more as well as the defrost and heat. But, is that a normal drop?

[TheForce]

Its normal. Every car gets lower mileage in the winter due to colder weather and winter gas. Dont be surprised if it drops more during the winter.

[abq sfr]

Originally Posted by johnny51981

Ok, first of all, my Average MPG only reached up to 45.4 in the almost 8 months that I have owned it. I'm satisfied with it since it is much better than my 20 MPG Blazer that I owned prior to.

Now that we have had the time change and the colder weather, it has dropped almost a mile. I understand since I'm using the headlights now, using the windshield wipers more as well as the defrost and heat. But, is that a normal drop?

TheForce is right... You don't indicate where you are from so its not clear how cold it gets there. But lots of things contribute to lower efficiency when it's colder, like the gas engine (ICE) running more to maintain it's and the catalitic converter's temperatures, you might have the heat running taking the heat from the ICE, ethanol in the fuel for cleaner air in places with air inversions (like here in Albuquerque), also check your tires for pressure, if you have not checked it since it was hot, they might need some air. I've dropped from 57 to 51 due to those factors, plus more short trips Christmas shopping, short trips will kill your mpg too.

[donee]

Hi Johny...,

Not sure where you are, but most likely its not someplace cold and snowy if you are only getting a 1 mpg drop.

Here in Chicagoland, I am running at about 48.5 mpg halfway through my latest tank. I had a buisness trip, and that meant driving when the roads were clear to the airport at a constant 62 mph for the majority of those drives, then allot of stop and go. Rather than in a conditions that permit allot more gliding. That was just after I finished up a 58 mpg tank, and refueled. Then it got cold, down into the low 20's at the time I leave for work in the morning. That means using the defroster allot, and actually running the heater to keep the windows clear.

Additionally, the tires are using allot of force to be pushed around in a circle, because the rubber is stiffer. And the air density is allot more, which means more air drag.

To cap it off, we had some snow, and I also needed to leave work later than usual, so I hit the teeth of the rush hour, which meant allot more stop and go, rather than slow and go. That was probably the majority impact. As its difficult to keep the battery up above 5 bars, where it will let one pulse and glide. And the car is not staying in stage 4, if it gets there at all. And the headlights and heater are working for an extra 40 minutes for the 23 mile commute than they normally would.

Anyway, yea, winter has a real impact on mileage. So far that impact is 17 % on my usual spring-summer-fall mileage. Could also be a switch over to winter low emissions gasoline in that mix. I noticed Diesel was now up at $3.54 a gallon around here, after being lower than gas for the summer. Which tends to indicate that stations have switched to the winter fuels.

Still, this is 20 mpg better than my old Saturn SL2 would get in typical summer weather, and these traffic conditions. Guess I can't complain too much - HA!

[Bob64]

actually, I think stiffer rubber would increase gas mileage which is why people inflate their tires above recommended values...

[donee]

Originally Posted by Bob64

actually, I think stiffer rubber would increase gas mileage which is why people inflate their tires above recommended values...

Hi Bob64,

You are confusing rubber stiffness with tire sidewall deflection. The tire rubber sidewall is in buckling mode, and will flex, no matter how stiff it is. The amount of flex is governed by the tire pressure. Stiffer rubber requires more work to be flexed the same amount. So each revolution of the tire requires more work as the portion of the sidewal directed to the ground is flexed and released as the tire turns.

So, yes, higher air pressure will improve mileage, as it reduces the side wall flex. But, no, you are wrong in saying stiffer colder rubber tires will need less energy to roll.

[johnny51981]

Sorry, I live in Kent, Washington (about 20 miles south of Seattle). My average commute is about 20 miles per trip one way with no traffic (I got the opposite direction) between work and home and then on alternating weekends, I'll drive around 10 miles with few stops.

We have had some pretty cold temps here as of late, but not as cold as other parts of the country.

I'm still happy with my mileage, even though it has gone down a bit for the winter.

[barbaram]

It happens to all of us who have colder temps. check the mods forum about blocking your grill.
check your tire pressures
if you have a garage you might want a block heater...
but as you said the mileage is still better than you used to get!

[johnny51981]

I wish I had a garage...but I don't live in a house. Don't get me started on how much I hate apartment living.

[nerfer]

Originally Posted by donee

Hi Johny...,

Not sure where you are, but most likely its not someplace cold and snowy if you are only getting a 1 mpg drop.

Here in Chicagoland, I am running at about 48.5 mpg halfway through my latest tank. I had a buisness trip, and that meant driving when the roads were clear to the airport at a constant 62 mph for the majority of those drives, then allot of stop and go. Rather than in a conditions that permit allot more gliding. That was just after I finished up a 58 mpg tank, and refueled. Then it got cold, down into the low 20's at the time I leave for work in the morning. That means using the defroster allot, and actually running the heater to keep the windows clear.

Additionally, the tires are using allot of force to be pushed around in a circle, because the rubber is stiffer. And the air density is allot more, which means more air drag.
:

Okay, normally I would just try to ignore this, but if you insist on using the phrase "a lot" so much, you really need to know it's two words, and that the single world "allot" means to parcel out, ration items, etc.

Yah, yah, goe ahed, Kall mee the Speeling Natzi. But since the rest of your grammar and spelling is fine considering the medium used, I hope you're receptive to knowing where your mistakes that really stand out are.

Also, I'm not sure that stiff rubber reduces mileage, but cold air does reduce the air pressure (p=t/v), so the tires will need to be pumped up a bit in cold weather.