Colder weather has zapped my mileage to 44mpg

sure, but posts won't take all caps, don't you know?

 

Filled up today, 272 miles took 6.546 gal's / indicated mpg at 44.2

actual was 41.55.

You will not get 50 mpg in the winter living in northwestern Oregon.

Also I have Michelin Energy Saver Tires with 44 psi of nitrogen in all 4 tires, (max sidewall pressure), and I have 0X20 Moibl one motor oil in the engine with 4 quarts so it is not over full but at about the 3/4 mark on the stick.

Everything for max MPG's yet only 41.5 MPG's, a looooong way from 50 mpg's.

alfon

 

If I ever finish a tank I'll post more specifics, but 50 mpg in the winter is very doable in Kansas, at least on dry roads. I could see in nw oregon not getting there due to all the climbing, and i think alfon earlier mentioned lots of wet roads, too. There is not enough spare HP for major climbing in an efficient manner. Still 41.55 probably beats most of the other car choices in the same conditions.

 

Interestingly, the OP ended:

You've obviously missed the underlying philosophy of this hijacked
thread, it has nothing to do with reason or reality.

To help you get in the proper mindset, here is a simple

. . . . . . . . . . --> TWO STEP PROGRAM <-- . . . . . . . . . .

Step 1: Repeat after me,
"I want what I want, because I want it, and I want it NOW."

Step 2: Repeat on your own, ad nauseam.

 

My most recent data collected from 22 long hwy trips can be found in my OP in a different thread:

http://priuschat.com/forums/gen-iii-2010-prius-fuel-economy/71937-influence-speed-temperature-weight-mpg-3.html#post1026228

It shows very nicely how much low temperatures play a major role in the phenomenal MPG hit in the 2010 Prius during winters and how much less the influence of speed really is…

Nice!

 

Nice chart.
Looks like the Prius's comfort zone is the same as it's owners.

 

Sorry - I didn't read all 11 pages of posts - I can only say that using ECO mode does help as it does avoid (in city driving mainly) the engine to idle at traffic lights or stop & go traffic, instead of staying off, to provide heat to the interior. I know this to be true, because if I drive in normal mode with 5-6C or less, when at a traffic light with enough battery charge, the engine still would go on and turning off the heater would shut down the engine immediately - the same would happen after a few secs of pressing the ECO button.

The air coming from the vents is a bit cooler than expected, but it does come warmer when the engine is warm again after driving at speed. It does also turn down the fan a notch, so even if the air is cooler it is not uncomfortable.

One could turn down the heater completely, but I am pretty sure that the fuel savings will not help global warming...

I also set the heater down to about 20C instead of the standard 22C (in the same way it would make sense to have 24C in hot days instead of the same 22C) to reduce, if at all, fuel consumption. I have not made any statistic to see if reducing the temperature would have any notable change in fuel consumption. Moreover, I don't think that turning off the A/C button would make any change. The instruction manual is a bit fuzzy on this, but it states that "around 0C" it will not work. On my Polo it would turn off at 7C, if I remember correctly. Turning A/C off does increase the chance of moisture in the inside of the windshield, so I would rather keep them clean than save the planet that way....

 

For the first 10,000 miles of driving my 2010 Prius averaged 53 MPG and this was driving in New England during the spring/summer/fall months. However, since the cold December weather has arrived my gas mileage has dropped to approximately 43 MPG. Initially I was a little surprised about the dramatic drop but have learned that cold weather has a negative impact on MPG for various reasons including, winter blend gasoline, lower tire pressures and other factors.

Although I am disapointed with the dramatic drop in MPG I now have a little better understanding on the reasons why and can only hope spring arrives soon.

I did drive my Prius down to Florida (51 MPG ave) and once there I easily averaged 55 MPG without much effort. So it does appear that weather is a factor.

 

If it's purely about the money, here's how the math works:
Compare to a comparable car - like the Matrix or something similar in most respects aside from the engine, which will typically cost about $3000-4000 less than the Prius.

Don't do your "lifetime" calculations based purely on winter numbers with a full passenger load - do it based on year-round numbers with typical loading (if you only drive it in the winter with 4 passengers, then so be it).

Do your calcs based on $2.75/gallon gas, then do it again with $4.75/gallon gas - because it will get back there someday, probably sooner rather than later.

With 15k miles per year, it's something like an 5 year payback based on a year-round average which matches the EPA - assuming gas stays cheap for 5 years. If gas goes up anytime soon (or if your miles are higher), the payback is shorter - possibly significantly shorter.


And if all that gives you a headache or annoys you to read, then it's not really about the money, is it?

 

I'll supplement that math with my own mileage for the past week & a half since I got the car:
Total miles: 800 - mix of about 75% freeway (doing 70+mph) and 25% "around town" (in the 30-50mph range). Typical drive was about 35miles, one trip was 250.
Moderately hilly terrain - no real steeps but plenty of ups and downs. Total altitude change max 400ft.
->Temps haven't exceeded 45F the whole time and have been mostly nearer 20F. <-
Some rain/snow driving but not heavy - did have to defog front & back a couple times though.
Minimal passenger loads (just me 85% of the time).
No grill blocking but that is very very high on my to-do list.

Total mpg (miles divided by gallons): 44.5 (give or take a 10th). Shutting off the heat for the first 5 miles or so makes some difference, but I didn't always do that. I did, however, wear my down winter coat from LLBean almost all the time.

I wasn't real happy about seeing anything under 50mpg, but now that I see it in context, I think it's pretty decent. With grill blocking I might get 46mpg - which I can live with 3 months out of the year. I'm betting I can stay above 50 in spring/fall and break 60mpg in the summertime, which should put the year-round average comfortably above the EPA estimate.

"Your mileage may vary."

 

good informational post. you get 1-1.5 mpg improvement with grill blocking but only because your type of driving. i saw a much greater improvement on my SPM but it drives a much slower and shorter route. its trips 6 miles at mostly 35 mph.

 

Once I get back to my typical non-holiday driving, many of my trips will be under 10 miles so the blocking will probably be even more important then.

I'm actually really pleased that the Gen3 can do 74mph and still have around 44mpg - I will probably settle in at 70mph to squeeze out a bit more, but I'm really REALLY glad I don't have to slog along at 65 to get in that FE range.

 

I have a 2007 touring. I am from Oregon as well. Unfortunately, my morning drive in the winter is the perfect storm of bad gas mileage. 5 miles uphill. With snow tires my mileage is down to around 34 mpg. I get over 40 in the summer. I would be quite happy with 44 mpg. The good news is with my short driving distances, I only fill up every 3-4 weeks.

 

What sort of difference have you seen with grill blocking?

 

i have a 2007 and my typical drive is 58 miles twice a day @ an average of 75 mph, winter or summer.
mileage does vary quite a bit due to rain/snow, temperatures, and headwinds. in the heat of summer i get 54-57 mpg, but in winter mileage can drop as low as 35 mpg with slush, a headwind and/or very cold temps (-10F to -30F).

i'd say on average i get 55 mpg in summer, and 43-45 mpg in winter, over the season.

when i go on shorter trips to work site #2 (25 miles), i drive much more slowly (55 mph) and usually average well over 60 mpg in summer and over 50 mpg in winter no matter how cold it is.

with respect to the comment by another poster on how Volkswagen diesels never decreased mileage by this much, i recall having a non-turbo Rabbit diesel which averaged approx. 50 mpg in the summer and 40 in winter, which seems pretty much in line with what the Prius is giving me.

considering what my other vehicule is, (a Durango with the heavy duty trailer towing package) i'm quite pleased with the economy. i hope to keep the vehicule for at least 300K miles, which will represent fairly significant savings.

francois

 

Diesels are hit by winter fuel too. Winter diesel fuel is essentaily kerosene which has a lower heat output, but wax does not come out of suspension in cold wx like it does with summer diesel.
Now that we are running ultra low sulphur diesel, I don't know if winter diesel is still required or not.
The price differential of ULSD makes Diesels make a lot less sense economically now. Used to be the cost per mile of Diesel was lower based on fuel cost, not true anymore.

 

I am curious, as to what your gas mileage was during the summer months?

I live in Portland but being the NW, I'm not expecting 50 mpg during the winter months. If it drops to low 40's during the winter I'm just going to say that's the cost of living in a wet, cold enviroment. The benefit being eveything is green and beautiful. During the Spring and Summer I'm hoping I can get closer to the magical # of 50 mpg.

You or any NW owners, I'd like to hear what you averaged in Summer, Fall, Winter and Spring.

 

Tom183, your posts are spot on. It took me a lot longer than 10 days of car ownership to reach your level of understanding.

 

Diesel also output cabin heat very slowly. If someone believe TDI will not get lower MPG in the rain, snow or with head-on wind I would like to see the data.

 

Thanks, man - I've been spending an inordinate amount of time soaking up the info here on Priuschat, which is a big help. :thumb:

I'm hoping to find the courage to try doing some mods (block heater, fog lights) myself instead of going to a mechanic - it's not that hard, is it? The info provided here is plenty detailed enough.:rockon: