BOOM! Winter fuel time!

Actual mpg or FCD?

 

I cant get over about 45mpg now with 4500 miles.

 

My drop so far has been fairly minor which I suspect is due to the temp drop. I don't know when Michigan switches to the winter blend or if we run it all year long.

 

I believe it is required by the EPA to limit emissions when the weather gets colder.

 

what you are seeing is typical winter performance and is not unique to the Prius, hybrids, etc. all cars go thru the same decrease in mileage. that is why i breakdown winter and summer mileage.

 

**edit**

i only have one winter tank so far, but this one i am on is gonna be about the same. my mileage drop is going to be more (about 6-8 mpg at this point) due to my type of driving. short trips, infrequent freeway. and just a 7 mile commute at street speeds.

even with grill blocking, i dont hit 155º until my commute is about 65-75% complete and that is with relatively mild temps in upper 30's to mid 40's

 

vendor no, locale yes. different weather conditions do require different formulations of gas so the amount of energy per gallon of gas will vary slightly. but the driving conditions is what will play the biggest part.

the longer the commute, the less the effect. on paper, the difference is only like 3-5% if just taking into account the change in gas. but keep in mind

1) colder temps, longer warmup. short trips take the big hit here. the defrost greatly affects your mileage because it has to run an electric compressor to work, the heat will only affect you very little if at all (it does a little because running the heater at low speeds greatly increases warmup time)

2) snow, rain, etc. increases rolling resistance. in both cases, slower speeds, more resistance.

3) cold air is denser, heavier. more wind resistance.

so , ya the gas makes a difference, but with anything that maximizes performance, everything makes a difference.

parting shot:

i live in a mild climate but with 100% humidity EVERY morning (onshore marine flow averages like 360 days a year) so hard to avoid defrost. one thing i did do back in my more fanatic days was to warm up car, then crack windows to keep windows clear and blast the heat. since defrost is a major hit on your mileage, i tried this. it did seem to increase the mileage, but did not work well with the rainy climate we get here.

 

summer formula gas does not stay mixed well at relatively high cooler temps. some formulas become unreliable at temps as low as 45º.

biggest thing is to prevent gas line freezeups. winter formula gas has been around waaaay longer than concern for the environment. granted, we have a lot more formulations due to environmental concerns.

there was someone who posted a great pdf detailing different options.... there was like 45 summer formulas, twenty something winter formulas and only the southern gulf coast of Texas and florida never changed formulas.

 

Here in Oregon where Ethanol is King our last tank was a dismal 41 MPG, calculated. Temps ranged from 45-55 degrees, but this is winterized gasoline which has all year long 10% Ethanol, now with winter the refineries are probable putting in 20% Ethanol,

So, if they are not why did I take a 5 MPG hit in MPG's?

alfon

 

I doubt they would add more ethanol as the current Rack price for ethanol is higher than that for gasoline. It would not make economic sense to do what you suggest they are doing.

 

My fuel economy has dropped from 56-57 for a tank average to 53-54 in the past few weeks and I have been using straight gasoline with no ethanol added. We still have a choice of what blend we want to use. It can be from 0% to 85% ethanol at the pump.

 

Hi All,

Overcast and Rain have predominated on this tank, and I am half way through it at 60.9 mpg, versus better than 68 when it was warm/sunny and driving on summer gas.

 

Donee, what do you charge for efficient driving lessons? I try to anticipate traffic and lights and glide where I can and run my tires at 42/40 but I'm nowhere near even 60. I do someday have to read the many threads here on hyper-miling.

 

Hi DetPrius,

I get that mileage mainly by route and drive time selection, besides the usual hypermiling stuff.

The Prius takes allot of driving before it will lock into stage 4. You want to do this portion of the trip at slow steady speeds, with a minimum amount of stop-light waiting. Doing this portion of the trip at high engine output eats gas. I am grill blocking this time of the year, and tune the number of slats that I close off depending on when the Stage 4 will lock in. In this low 40's mornings, low 50's evening I have 2/3s of the lower grill blocked (leaving just the lower left open), and the upper grill complete blocked (Gen II car - Gen III requires different blocking configuration). Based on temperature meter indication I had before the local police made me take it out, this would get the engine in the 90 to 92 C range about 10 miles into the drive.

I am also driving at 53 mph in the right lane when I am on the interstate during a medium traffic time of day. I think half of my mileage drop these last few tanks is the cold weather, rain and head winds this time of year on that portion of the trip. The other half is probably Ethanol in the gas.

I do not take the interstate on the drive home, as its too unpredictable, and the only route to it on the drive home is full of heavy traffic, and lots of stop light waiting (about 10 minutes worth to go 3 miles) which drops the car down into stage 3 for the first bit of highway driving. That first bit of highway driving is unfortunately (for mileage sakes) relativly unclogged and so during that time the car will run rich to get back up to temp and charge the battery, while I am running at highway speeds. All that stop and go to get to the higway results in lower battery SOC. And I found that was a big hit on the mileage. So, I take a surface street route now, as I fond a route that although it has stops, I can time it so they are breif. I also found that this route draws a line that cuts a big dog leg going the interstate route. So, its suprisingly about the the same time as the interstate route, when there is an average amount of interstate traffic.

In the summer the interstate route during the medium traffic time of day is about 65 mpg, and surface street route is about 70 to 75 (depending on how many lights I hit) mpg. Although if I get a strong tail wind and steady traffic the interstate route can reach 75 mpg. I am using the SHM pedal method for this at 53 mph, and I have some aeromods which help out the SHM up to 53 mph from 50 ish.

I am by no means the best mileage Prius driver on Prius Chat here. Look around and you will see many that get better. I had a MYCANSCAN auxiliary dash board in my car for some time, and allot of figuring out how to do this was with feedback from that dash board. The Prius is woefully short on gauges. The MYCANSCAN has color change bar graphs, and over time one can recognise color patterns if you place the screen close to your line of sight out of the car, without looking away from the road. But this makes it presence obvious to the police, who are not interested in common sense, just what they can ticket (which is their duty).

 

What are the stages you are talking about? Where do I find that info?

Thanks!