Colder weather has zapped my mileage to 44mpg

According to Wayne's simulator (proven to be very accurate) predicts that the crosswind are worse than the headwind.

His analysis also show it takes 11% more energy to cut through 22 deg F vs. 80 deg F air. 1.3 hp extra loss at 65 MPH.

Mechanical drag almost double due to the cold with 3.5 hp loss at 65 MPH.

 

Interesting... My worst mileage was with moderately strong crosswinds (which would be a negative in both directions on a round-trip).

 

I'm new (first post) -- but am on my 3rd prius -- package 5, 17" wheels. I can't seem to get near the mileage I did out of the '04 and '06 models I had. I only have 160 miles on 2010 - got it end of Dec and it's been cold here in Colorado ever since. I'm getting 42 to 44mpg driving all the time in the economy mode. I'm an old f--t (82) and I try to drive for maximum mileage. Am I expecting 50 to 60gpm to early? Does the car need break in time? What pressure should I use in the tires? Should I take this back to the dealer? Any suggestions will be helpful.

Ps. Haven't tried the parking assist, lane guidance or radar yet. Are these just "braggin' rights gadgets" or do they really work?

 

Welcome to Priuschat, Pleasantp! Your mileage is 'normal' for this time of year. Some have said the 17" hurt them somewhat, but I have the 15" so what do I know? You can improve your mileage with several changes, if you wish. The 2010 has some advantages over your former Gen II Priuses, but the 1.8L ICE is a hindrance except when you need the extra HP.

Your tire pressure should be no lower than the placard Toyota stamped on the car, and lets say no more than sidewall max from the tire manufacturer (typically 44 psi, some tires 51 psi). Between the two, pick your tradeoff between ride harshness and fuel economy. Personally, I had to inch my way up a couple of psi at a time over a period of months, and now run max sidewall, mostly.

There are threads here to help with most any driving pattern, but respond here with your typical driving (distance, hills, traffic, etc.), and someone will start to make suggestions.

Winter techniques include grill blocking, engine block heater, trip planning to minimize warm-up penalties, slower speeds to offset denser air, etc. There is a great thread over at cleanmpg.com titled something like Winter Survival Guide for Hybrid Owners.

Overall, the fair weather mileage of the 2010 seems consistent with the EPA rating, while the winter hit has disappointed some more than others. Some of the really high mpg results have been a bit elusive to date.

 

If by "cold" you mean 15-20F, you're showing the typical mileage hit.

If by "cold" you mean 40F, you should be close to 50mpg (assuming a lot of other things).

 

Absolutely!

True if you drive it like a normal car, but if you try really really hard, slow down like grandma, implement all the tricks that goes from blocking the grille to freezing inside the cabin, maybe you can reduced your winter MPG from 30-40% to 15%... Maybe...

Consider all the states and their hwy speed limits.

In 19 states you can drive legally at 70 MPH and in 13 of them at 75 MPH (with 2 of them allowing 80 MPH! in specific areas). So, 19 + 13 = 32... therefore, in the majority of states you can legally drive considerably faster than what you consider excessive, and most people from Europe and other parts of the world consider the American speed laws extremely conservative...

Come on...

Se "tricks" on number 2.

Somewhat agree... in some parts of the world not until summer...

How about hearing from a world some Prius owners don't know about...

TDIClub Forums - View Single Post - 2010 Audi A3 TDI

 

The temp today hovered around freezing (quite warm by MN standards), so I took advantage by getting much-needed errands done. 101.8 miles of very mixed driving (32 MPH average) resulted in a displayed efficiency of 54.1 mpg.
.

 

Just came back from one of my trips and run a speed test as nicely suggested here. My way was mostly flat but I took 3 samples for each speed to minimize effects of minor terrain irregularities. This was composed of 10-mile stretches each piece after the car was well warmed up (water temp above 195F), steady all the time, with cruise engaged, air temp of 32F, dry, no significant winds. These were also MID numbers, please remember that real numbers in the Prius are at least 4% bellow MID but my average after 28 hwy trips is actually 6.5% bellow (can show you the data to prove it).

75 MPH: 42.7, 42.7, 43.1: 42.8 (average)

70 MPH: 45.4, 45.5, 45.8: 45.5

65 MPH: 50.8, 52.1, 52.6: 51.8

Just one shot at 80 MPH revealed 39.4 MPG.

Subtracting 6.5% for the real MPG (this can vary anything from 4-10%), my Prius was able to meet EPA for those who care (48 MPG) only at 65 MPH (70 MPH was the limit in the hwy tested) in very good conditions for the winter in this part of the world with the grille blocked and limited heat inside the cabin.

I will run a similar experiment when temps are like 10F or bellow and I suspect the real 48 MPG will not be achieved above 50-55 MPH...

 

User mileage reports:

	Column 1	Column 2	Column 3	Column 4	Column 5
0	max	avg	min	cnt	model
1	64	50.9	40	20	2009 Prius 1.5L
2	60	49.8	37	66	2010 Prius 1.8L
3	59	49.6	43	10	2010 Insight 1.3L
4	58	48.1	40	11	2010 Insight 1.3L
5	50	40.1	33	27	2009 Jetta TDI

* - Fuel Economy

One should of course choose a vehicle that meets one's requirements.

Bob Wilson

 

I agree Bob, but you know what, sometimes a few extra MPG are not worth for if you know what I'm saying...

 

No problem. There are many vehicles available and each has their strengths and weaknesses. Pick the one that meets your requirements and life is good.

In October 2005, we bought a used 2003 Prius with 49,000 miles when the original owner sold it for another vehicle, not a Prius. They were happy and we still have the 2003 Prius. In May 2009, we sold our 2001 Echo, 30,000 miles to a co-worker and they are very happy with it.

Your 2010 Prius as a used vehicle can make someone very happy and you'll be free to find a car that better meets your requirements. At least you've had a chance to try the Prius.

Bob Wilson

 

Yep, the Prius isn't going to make everyone happy! My brother, a truck guy, say's "I'm never gonna drive a stinkin' video game!"

 

When selling your Prius, it may help to wait until the Spring huricane season. Go ahead and open negotiations on your next vehicle but let 'time be on your side.' You'll get a better purchase deal while your Prius can be for sale. Bad weather that shuts down Gulf production and you might get all of your money out of the Prius. ... Just a thought.

GOOD LUCK!

Bob Wilson

 

I'm curious where you get numbers for the states from and what the numbers are really supposed to represent? For instance, I found Map of maximum posted speed limits on rural interstates and [ame="http://en.wikipedia.org/wiki/Speed_limits_in_the_United_States"]Speed limits in the United States - Wikipedia, the free encyclopedia[/ame] and will say that the numbers there don't necessarily mean what you think. Per the above links, the max speed limit for your own state is 65 mph.

I grew up in California and last lived there from Sept 04 to 09. The only place where I personally have seen even 70 mph limits is on portions of I-5 such as those between the Bay Area and LA. Once you get into the LA area, the I-5 speed limit goes down (I recall even 55 mph limit stretches). For my ~24 mile one-way commute, the highways involved (85, 87 and 101) all had limits between 55 and 65. I can't think of ANY highways in the SF Bay Area in the Bay Area other than I-5 that had >65 mph limits.

In WA state, all the highways around the Seattle area have 60 mph limits. To top it off, people drive slow in WA and don't practice proper lane discipline.

In the limited time I've spent in Oregon (a few days), I observed highway speed limits as low as 50 mph. I don't recall any above 65, if there were even any at 65. http://en.wikipedia.org/wiki/Speed_limits_in_the_United_States#Oregon claims that Oregon's max speed limit is <70 mph.

The times I've been in Canada, I've typically only seen 100 kph limits (~62 mph) on the highways.

ken1784 I remember commented about highway speed limits in Japan but I can't find it. From [ame="http://en.wikipedia.org/wiki/Speed_limits_by_country"]Speed limits by country - Wikipedia, the free encyclopedia[/ame], it seems they're no higher than 100 kph.

edit: 65 mph is the max in California w/a certain set of exceptions. See http://www.dot.ca.gov/hq/roadinfo/faq.htm and http://www.dot.ca.gov/hq/roadinfo/70mph.htm.

 

Good data, and fwiw, consistent with what I expect. Damn good car, although I wonder how much better than a G2 Prius.

 

What would be a better place if not from the Insurance Institute for Highway Loss?

http://www.iihs.org/laws/speedlimits.aspx

I’m talking about the maximum legal speed allowed in the US… I drive in several different states… the argument of what speed is allowed in my state is poor, in fact, you actually got it wrong because the limit in my official residence state is 70, not 65.

In fact, my grandma hates to cruise at 65 MPH or bellow... it's not safe, people goes behind her shooting their light in her mirror and making obscene gestures, slow traffic is a common cause of jams and she hates being stuck, and she realized she does not have to drive it like grandpa drives his golf cart to be safe... just move on and get out of the way folks! No wonder the Prius has the misleading reputation of lack of power because people drive it so slow... it's not lack of power as we owners know; it's just part of the effort of being FE, and in the winter, it's more like a desperate one... it’s the eco mode inside of each one of us who applies

 

Thanks Sage. I suppose this proves there is nothing really wrong with my Prius... the occasions where I'm seeing really low MPGs (bellow 40 for indicated) are caused by adverse conditions, most important of which are low air temperatures and higher speeds. But it also proves meeting EPA numbers in the hwy is a very difficult task in the new Prius during winter.

 

Thanks Bob, maybe spring is good time….

But in the summer, since I'm looking for TDI diesel, diesel prices in the summer tend to get lower while gas goes up... so the Prius may get less attractive as a trade for the A3...

The A3 dealer in WI called me…. They just got one 2010 used that could be traded for my Prius but the low mileage on it precludes the deal... I'm not paying more than I told them... so; it looks like I will have to wait for a good while or who knows if I will ever get a deal...

 

.

Really! Did you ever doubt?

If by "guess" you mean data carefully collected from 15,0000 miles worth of trips... yes my elegant guess (attached) reveals pretty clear that air temperature is the major problem for FE in the Prius... see how the MPG tracks up and down really nicely with air temperature while speed is all over the place? Not that speed does not have its influence... it does as a I showed in my little experiment in post 528, page 53, but if one does not see that air temperature has bigger influence than speed, one cannot be helped... BTW most “tricks” we know about (block heater, grille blocking, turn heater off) are meant to minimize cold air effects, not speed…

If driving 2-3 360-mile weekly trips at average speeds of 66 MPH is not slowing down enough... better ride a scooter...