View Full Version : Does the winter mixture of gas lose efficiency?

01/03/2008, 07:23 AM
I can cruise at 60 to my scan gauge reading in the 13-14 range when normally that is what I get in city driving. I am used to seeing the 18-19 range on the highway. These last 3-4 tanks I have averaged a little less than 13 mpg which is down about 2 mpg. Not a lot but since I have noticed this trend from the first low mpg tank I have been driving a little too gas conscious so really it would be worse if I was driving normal?

Is this the case with anyone else?

01/03/2008, 07:57 AM
Take into account that you are also consuming A LOT more gas with the cold engine startup process, and possibly winter gas mixture, lower psi tires at cold startup, harder vs. softer rubber issues, denser air/aerodynamics to push through, higher viscosity lubricants/engine/tranny/transfer case/ differentials/ bearings to decrease wheel horsepower, contraction and increased friction from any moving surfaces in contact, etc. etc. etc. Of course these could all be debatable, but they don't help- thats for sure.

All very small variables, but working together to decrease your mileage:mad:

The only benefit from the winter weather I can think of just as fast is colder, denser air. Plus, colder and denser gasoline combined and adding some efficiency to the engine after it is warmed up to allow more efficient engine output.

Yeah, winter will never allow your best mileage average. In my wife's old Acura I used to commute to work in all highway miles 2 hours round trip, I would go from a high of around 440 miles per tank in mild warm weather to around 350 per tank in the winter no matter how much babying I did while commuting.

Yeah, you could drive "normal", but when you start to get in the low 200 miles per tank, you'll see why that won't help. But the again, "normal" means a lot of different things as well. :p

01/03/2008, 09:24 AM
Actually (from my limited comprehension of the topic) winter mix on fuel is actually higher in energy. The summer mix with ethanol is less efficient. MrCrowley hit the nail on the head with less efficiency of the machine in the cold environment. The only other factor that I can think of is additional rolling resistance from road conditions (wet or snowy roads).

You can play some games to attempt to recoup the loss but I doubt they will pay for themselves. Lower viscous fluids will operate more efficiently at low temperatures (better off using synthetics year round tho as they are effected less by low temps). A block heater will help on start up but won't make any difference after the engine has reached operating temperature. The one thing that would make the biggest difference is checking air pressure often. During winter when the temperatures swing dramatically, your tire pressure will be significantly effected (2-3 lbs probably). Try inflating your tires during the coldest part of the day to the lowest pressure you would like to run at (say 32 psi). Then in the afternoon the pressure should still be in the safe zone but a more optimal pressure (say 34-36 psi).

01/03/2008, 09:40 AM
This post has made it occur to me what do most of you run your tires PSI wise?

01/03/2008, 10:12 AM
Using the defroster uses the air compressor as well which could contribute to the drop in mileage.

01/03/2008, 10:21 AM
I find that I get the most even wear when I run my tires at 34-36 psi so I try to keep them at 34 year round. That's for on road. Off road is an entirely different story.

Different tires will 'feel' or react differently so you'll have to use trial and error to find what works best for you. Just make sure you keep it in the safe zone recommended by the mfr (I'd never run over 36 just for fear of breaking a bead).

01/03/2008, 11:27 AM
I wondered cause my OEM tires had a max of 40psi but when I had them in for rotation the shop guy said 29 psi. So I need to add a few PSIs tonight.

01/03/2008, 11:44 AM
Thanks for that infomation....I need to check my psi....My tires max out at 44 PSI.

Im leaning towards the defroster as the culprit.
I have always only used synth oil as well.

01/03/2008, 12:22 PM
Also have your front end alignment checked.

BTW, I'd try running at 34-36 psi for a while first. IMHO 40-44 psi is higher than I'm comfortable with. IMHO

01/03/2008, 12:56 PM
I've always experienced poorer mileage in the winter months...currently getting about 210-220 miles per tank.(until the light comes on)
I always let it warm up for about five minutes before I roll, so that doesn't help.
I'm currently running 45-50 psi in my Terra Grapplers, & run about 60 psi for highway use in my Mud Grapplers. I like to go on the high side for less rolling resistance, but admit that's a little higher than most would use.

01/03/2008, 02:01 PM
Im more of a fan of maxing out the PSI's too. Im going to try to roll around town with a little less for a day to two this weekend and see how that works.

I get about the same 210-220 and the light shows up ....then I fill up about 19 gallons or a little more.

01/03/2008, 02:47 PM
Im more of a fan of maxing out the PSI's too. Im going to try to roll around town with a little less for a day to two this weekend and see how that works.

I get about the same 210-220 and the light shows up ....then I fill up about 19 gallons or a little more.

When does your light come on? I have put 20 gal in and have not seen the light!:eek: I've only had my VX for a couple of weeks though. It could be burnt out I guess.:confused:

01/03/2008, 07:08 PM
Heck, I'm punch for high 200's, low 300's, put almost 19gal in and haven't seen the light yet. (Thought here: Maybe I need to check the the light tomorrow morning at lamp test when I start to work.....hmmmm) Got 20mpg once, stays around 17 to 19, just like to book said. (Though I am keeping an I on my oil now.)


01/03/2008, 07:28 PM
Doesnt the book say 15-18ish?

My light is random sometimes it comes on when I fill up with a little more than 19 gallons and sometimes it does not. I normally do not trust the light or follow it and just fill up when I meet the last bar by the E.

01/03/2008, 07:29 PM
I think the tank is 22.. I have seen the light at 20.5

01/03/2008, 07:37 PM
22 gallon tank - I also air my tires up to 46 pounds as a normal pressure. Tend to get about one additional mile per gallon out of it at that pressure, but it does make the ride much rougher and noisier. I've got V-rated radials - I'm not sure if I'd recommend too much air on tires with thinner sidewalls.

-- John

01/03/2008, 07:39 PM
Yeah, I think the book has it as 22.5, though, I tend to fill the neck up to the top, but not pouring out on the cladding.
Since out temps have been kind of nuts here, teen's at night, 50's during the day, I do try to switch to non-ac-assisted modes of environmental control asap, but sometimes it stays on all the way to work. Thought about trying another route to work, hiway but longer, but too much on my plate to play with the numbers right now.

01/03/2008, 08:10 PM
22.5 gallon tank