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What are others experience with cold weather mileage?

Since cold weather arrived here in Connecticut my mileage has dropped from 47 mpg to 40 mpg in mostly short commuting and shopping trips. Longer trip mileage, especially on expressways, is still good.
 

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Len, what you're experiencing is normal. Keep in mind that the ICE needs to run longer and more often to heat up and then to maintain that heat. Mileage typically drops in a conventional car also during cold weather.
 

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You guys aren't doing too bad!! My mileage went from 48-53 avg to about 35 in this frigid time of the year!! I guess I can't complain...My Blazer would only be getting me about 9mpg right now!
 

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Len, what you're experiencing is normal. Keep in mind that the ICE needs to run longer and more often to heat up and then to maintain that heat. Mileage typically drops in a conventional car also during cold weather.



..................................WHY?..............................(unless you remote start it and allow it 15 minutes to heat up!)
 

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I'm usually in the mid 40s, but now I'm sitting in the 30's. The strange thing is that the AVG MPG seems to change very quickly, even after 200 miles. I can go one block and watch it drop .2 mpg. Not sure why.

Also----why is the mileage so much worse with the heater on (and I keep the A/C button off) than in the summer with the AC on?????


Happy Holidays to all
 

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firepa63 said:
Len, what you're experiencing is normal. Keep in mind that the ICE needs to run longer and more often to heat up and then to maintain that heat. Mileage typically drops in a conventional car also during cold weather.



..................................WHY?..............................(unless you remote start it and allow it 15 minutes to heat up!)

..................................
 

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Winter Gas Mileage

I normally run slightly over 60 mpg, but am down to 54 mpg with the cold weather.
 

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hyperion said:
firepa63 said:
Len, what you're experiencing is normal. Keep in mind that the ICE needs to run longer and more often to heat up and then to maintain that heat. Mileage typically drops in a conventional car also during cold weather.
..................................WHY?..............................(unless you remote start it and allow it 15 minutes to heat up!)
Because the car won't shut off at stop lights or while downhill coasting for much longer into your trip. On a warm day, the engine warms up very quickly and can shut off when not needed. If you have short trips on a cold day, the ICE can run 100% of the time which makes the short trip and cold weather combo the worst possible case for mileage in the Prius.
 

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Not to mention that the car will run in open loop mode which averages about 35 MPG until the coolant gets warm enough. Even with the storage tank, the cold block will absorb that stored heat quickly and practically nullify its effects in frigid weather. Sure, you'll have more of a head-start than if the storage tank didn't exist, but still very cold for an engine, and take longer to reach closed loop mode temp than a nice spring day.

And if the cabin occupants ask for heat, well then the system will set the coolant threshold even higher and not allow much leeway for idle shutdown in order to keep the coolant hot enough to sufficiently heat the heater core.
 

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26 mile commute to work and I normally get about 62 mpg in the summer. 17 F today and got 59.2 mpg.
 

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Last tankful 45.9, my lowest yet. Current tank half way through, around 44, mind you mostly in single digit temps, snow tires (inflation 33/31), driving in snow, some mountainous driving...I am thrilled! :D
 

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Well, I'm feeling a bit better today. Two days ago I was showing 19.1 mpg with half a tank gone. Warmed up to 40 yesterday and today, took a couple interstate trips, and at fillup MFD showed 33 mpg. :lol: for me though some of you may be :( . Interesting that computing mpg calculated to only 25.6 mpg. Seems like quite a disparity even considering fill levels are never consistent.
 

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Milage

Don't rely on the computer readout for your milage numbers.
Calculate miles driven by amt. gas used for your real MPG figures.

I record digital MPG on display at time I fill up and calculate miles / gallons. The two numbers vary quite a bit. As much as several MPG apart.

Would like to know how the onboard computer is keeping track of MPG.
 

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Re: Milage

larry31 said:
Don't rely on the computer readout for your milage numbers.
Calculate miles driven by amt. gas used for your real MPG figures.

I record digital MPG on display at time I fill up and calculate miles / gallons. The two numbers vary quite a bit. As much as several MPG apart.

Would like to know how the onboard computer is keeping track of MPG.
i'd trust the onboard computer of my car before i trusted the calibration of the local gas station's gas pump...
 

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My usual winter trips are only about 5 miles over hills so I'm struggling to get more than 40 mpg. But the last 2 or 3 days I've taken some longer drives and have been happy to see the mpg bounce back up to 49 - 50 mpg. Whew!
 

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What I'd like to know is what kind of driving are people like Chris Cording doing that they get over 60 mpg on a regular basis!! If I stick to local country roads at 35 mph, I might be able to do low 50's tops, but over 60 regularly I can't imagine. Good for you, Chris.

I guess my driving is much more varied - some hills, highways, local roads with and without stops/lights, etc., long and short trips. Those non-congested 35 mpg roads would make a nice 26 mile commute every day. Most of us probably don't have that.

Anyway, my winter mileage, with my new Hydroedge front tires, is about 44 mpg, down from 48-50 in the summer. Temps range from 15 to 40 degrees here in north central New Jersey and I do wind up doing a lot of short trips.

Susan
 

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Time to 'fess up - I'm a gas mileage geek. I try to maximize my gas mileage for entertainment. Unfortunately, my commute is not conducive to good gas mileage (half interstate 70 mph, and half 55 mph with 14 stoplights). It is hard for me to get 60 mpg in the winter, but easy in the summer (this is for full tanks, not just the work commute).

So do I have "one of the really good Priuses"? Not really. My wife gets 10+ mpg less than me in her Prius. If I swap cars, our mileage changes accordingly. Good gas mileage is mostly a matter of technique. Here are some tricks:

1) More air in the tires. Both of our Priuses have 56 psi in the front and 54 psi in the back of our Goodyear Integrity OEM tires. The tire is only rated for 44 psi maximum cold inflation pressure, so do this at your own risk!!!! The higher pressure improves gas mileage, tire life, and seems to improve handling (less washy feel). Without extra air in the tires, you need virtually perfect driving conditions to achieve 60 mpg. This is good for about 5 mpg compared to the recommended tire pressure.

2) The most important trick to good gas mileage is to use your ears. Anytime you hear the engine RPM's increasing, you are turning the engine faster per mile traveled and using more gas. The goal is to keep the engine turning as slowly as possible (listen for a really low rumble sound). This requires slower acceleration, letting the speed drop off a bit going up hills, and easy use of the throttle. If your engine sounds like an angry hive of bees, you can forget exceptional gas mileage. Minimizing the engine rpm's is good for about 5 mpg.

3) Coast whenever possible. For example, if you are going downhill, let your foot completely off the throttle to stop feeding gas to the engine, and then lightly push the throttle to get to the "no arrows" zone. This is the "glide" mode. Coast every chance you get. This can add a lot to your mpg depending on the road conditions.

4) Anticipate stops and let off the gas early.

5) Exercise care with the climate controls. The climate controls make a huge difference in gas mileage. I will offer the technique, but the explanation of why it works is too lengthy for now. For heating, set the temperature to "max heat" and the fan at its lowest setting with "recirc." If you get too warm, then turn the heat off. For cooling, set the temperature at "max cold" and the fan at the lowest setting with "recirc." If you get too cold, then turn everything off. The windshield may fog when only using "recirc," so you may have to bump the "fresh air" button occasionally to clear the windows. This technique makes the automatic temperature control feature ineffective, but will maximize gas mileage while keeping you comfortable.

Of course, if you follow none of these suggestions, you will still get great gas mileage in the wonderfully designed Prius. But it really messes with people's heads when you show them over 60 mpg on the MFD.

Some personal records: 83.3 mpg on one 26 mile commute to work (by drafting, which I don't recommend). Longest distance on one tank 627 miles (too chicken to push the limit - DanMan has gone over 700 miles!). 62.5 mpg for a full tank. Current tank 55.1 mpg (getting lazy about the mileage game, plus winter effect).
 

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Just drove across WA state, mostly I-90 across the Cascade Mt.s. The temp was 35 to 37 all the way. Trip was about 350 mi. I kept to the speed limit or just a hair above all the way. I had just put on winter tires, Michelin X-Ice snow tires.

Trip over was about 48 mpg - about 2-3 mpg less than the summer usual.

Coming back, I put it on cruise control all the way, setting at 7 mph, except when traffic got a bit rough a few time. Just let it have its head. The mpg for the return was about 51 mpg.

By the way, the X-Ice tires are pretty steady at interstate speeds and seem to be a lot quieter than the OEM tires. Not what I expected! I'll leave them on until the end of Feb. But, I hate the black steel wheels. Tempted to spring for some hub caps.
 

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We just completed a 1500 mile round trip from Ruidoso, N.M. (elevation 7000 ft) to Tyler, T.X. (elevation around 600 ft), temps ranged from low 30's to mid 70's. Wind was always blowing, and always against us, sometimes up to 35 mph. Best mileage I could get on a per tank basis was 43 mpg. Worst was 32 mpg. This was mostly at 65 to 75 mph. I did notice at every fill-up that I could only coax in 8 gallons, even when one bar was showing. I know others have seen this as well. Car performed well, although cross winds could be a problem. I run Goodyear Comfortreads inflated to 42, 40. Front air dams are moved forward, and this seems to stop buffeting when following big rigs. I plan on getting the chassis stiffener and see what that does to solidify feel. Car has plenty of power for passing, and for me, the seats are comfortable, even after our return trip of 11 hours straight. My knees used to hurt after 4 or 5 hours, even in the XJ6 we just sold. We rolled over the 10,000 mile mark on this trip and car is only 7 months old! I do wish that it had a telescopic steering wheel, though.

Tom
 
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