Cold Weather Prius

brutal! i would try letting it warm up for a few minutes and see what happens.

 

How long are you running the block heater and how hot is it when you first start? How blocked is the grille? Do you use heat? Is the highway driving at highway speeds or slow traffic? If you're going over 40MPH, I don't think it makes a difference if you're in stage 4. However, if its slower and you would be pulsing and gliding, then getting to stage 4 would help.

 

It won't hurt the Prius if you let it warm up a little bit before driving off. At least then you will have heat so you don't freeze. The only thing it will do really is cause the MPG to suffer some. Remember the system gets the best MPG when it is up to normal operating temperature.

When it is real cold here, I tend to let ours run at least five minutes then drive off. By then the heat is working and I am comfortable.

Don't be surprised if you don't get S4 mode in your commute.

 

What I do is I start the car up and le it run a for a couple of minutes. That heat storage tank really works during the winter when the enigne warms up kind of hard. Because its winter I don't even bother much with the MPG most likely because the engine has to run in order to keep the car warm inside. We had 4 degrees cold and now it kind of went up a bit and sits into upper 20s during the day.

 

You'd be surprised how much opportunity there actually is for engine-off driving, even at -18°F...



But whether or not the engine runs is really a non-issue. It's the results that count...


That wasn't too bad considering how &%#$@! cold it was.


The results from this drive was better...

 

My setup is stock, just the MFD. No scangage here so can't see all the fancy numbers. What I do is reach the speed I want to go, then ease off the pressure very lightly on the accelerator pedal until I see the instantaneous mpg reading 60. If conditions are right (grade, wind, road etc) I have found I can hold 55 MPH fairly well. 60 MPH and over I have had no luck with. If I see the speed dropping off I will let it drop to about where the MPG is showing 50 or a little more and then speed back up to my target speed and start the process again. It also seems that the higher the SOC the higher I can get the MFD when attempting SHM. I only do this on short runs though. Long trips, I set the cruise and let it roll.

Hobbit wrote a great post on this on another site. But he was measuring both manifold vacuum and RPM.

 

Depending on your tires and pressure, you should be able to get nearly the same mileage at 55-60MPH. I would just watch the instant MPG as your guide.

Also, consider blocking the rest of the grille for the winter. With my lower grille fully blocked and the upper open, I max out at about 190F on the highway.

 

You seem well versed into taking advantage of the mpg.

I average about 35 mpg. Owned my prius since last week. If I drive the car nice and eas up on the gas I see the mpg 50+ but if I am in a hurry mpg is crap. I filled the tank up today for the first time and reset the odometer. Will see what results I get. What I did notice that car runs on battery only kind of rare even if I go slow or just cruise engine still kicks in and runs. What I do take advantage of is when I slow down or go downhill.

 

There are several things you can do. Adjust air pressure on tires. Check to see if they are LRR type tires. Change when wore out if not.

Learn about hypermiling techniques including Pulse and Glide.

Use synthetic oil.

Those are just a few tricks I have employed. By following those I have been able to beat the EPA estimates. Not as good as John above, but I am happy with what I get.

FWIW, it took me over a year to figure everything out.

In my signature below are some important links that pertain to hypermiling and understanding the modes of the Prius operation. Study them and practice P&G when you can. Don't drive the Prius like a race car and take advantage of P&G as much as possible. I don't drive like a grandma, but I don't have the pedal to the medal either. The key is momentum and not using the ICE or battery anymore than is needed.

Good luck and remember you can't learn all of it overnight. It takes time. Enjoy your new to you Prius.

 

Thank you dorunron I will do that.

 

Freebie: Air Pressure in tires. Try 42 front, and 40 rear. Adjust up or down to your preference. Less pressure gives better ride but sacrifices MPG. Do NOT exceed maximum tire pressure that is marked on the side of the tires.

I run our Michelin Energy A/S tires (LRR type tires) very expensive at 40F, 38R. If you look at my fuelly in my signature below you will see the MPG since I installed the tires. True data will be collected once one year rolls around. I have about six months on them now.

Remember the Prius gets its worst MPG during the winter and its best during the warmer drier months.

There are other things too like climate control settings. Lots of tips can be found here on PC. Do some reading in the "fuel economy" section forum. That should really help you.

Don't forget P&G that too is a freebie. It takes a little practice but after a while it becomes second nature and with practice you can get to where the whole process is painless and relatively smooth. It is all in how you work the go pedal. Remember momentum is the key.

Best of luck to you!

 

With all the changes I have made, I think the best thing was the tire choice. Air pressure helped, and the synthetic oil helped too, but when I went from the OEM Integrity to the Michelin that is when the Prius acted like a real gas saver.

With the OEM tires, my average was a consistent 45 to 48. With the Michelin Energy Saver the numbers have seemed to increase. I really won't know until another six months has passed.

I also must say that I did not see the good numbers doing SHM until I went with the new tires. So keep all of that in mind in your quest for SHM good numbers.

Honestly though, when you compare the Prius to traditional even low to mid 40's is better than most out there today with gasoline power.

 

I would venture to say that if you are getting 41, I bet the other guy is getting less because he too is fighting the same cold and the winter gas you are. All cars suffer from MPG loss during the winter versus the summer.

Winter won't last forever. It will be over before you know it and the good numbers will return in time.