Hi all, I've read some forums and there is alot of info on why MPG is worse in the winter and all that, but what I would like to know is how to improve it! I am getting between 40 and 42 MPG on my 2 week new Prius. The temperature has probably been above freezing, but below 45 F the whole time. I do not have a Garage to park my Prius in, and I don't even understand what this "Blocking" stuff is. So can you offer tips on improving MPG in the winter? I would really love to see 50 MPG for the first time on my car . Would letting my Engine warm up (by idling) before I drive it help? That is not something I currently do because I assumed it would hurt fuel economy. Please help, be a Prius Genius!
Engine blocking is merely blocking the lower grill on the car. I went to a local hardware store and purchased some round, black foam insulation (pipe insulation). The smaller sized stuff (1/2"? or 3/8"). I cut some lengths that would fit across the lower grill and wedged it in there. It didn't fit as well as I liked, because there are some plastic bars that run perpendicular (up and down) to the grill. I resolved this by cutting little "slits" into the piping so that the slits would line up and fit in with the vertical slats. Basically, it deflects the air and reduces the amount of cold air getting into the engine bay. This allows for the car to warm up more quickly and maintain heat better because you don't have as much cold air cooling the engine down. While I don't have the same mileage I was getting in the summer (62 - 63 mpg) I'm doing a lot better than I was this time last year (my last fill up was 59 mpg, last year, under the same conditions, it would have been 55-56 mpg). Don't forget to check you tire air pressures. They will decrease with the colder weather, so you'll want to pump them up again. I run mine at MAX PSI in the front (44 PSI for my tires) and 42 PSI for the rear. This helps with rolling resistance issues.
NO SPECIAL SKILLS REQUIRED ====================== 1) Scrape off the frost/ice from your front and rear windshield manually with a plastic auto windshield ice scraper and use the front windshield defroster and rear windshield defroster only when necessary and then so sparingly. Avoid using the cabin heater for the first 20 minutes. 2) Rather than warm up the car for a few minutes before driving it - if the windshields are clear and driving conditions permit - immediated start your trip and drive once you start up the Prius - however, donot push the Prius beyond the HSI eco mode during the first 3 to 6 minutes - allow the ICE to gently warm up while the Prius is moving forward to its destination for the first 6 minutes. 3) Park your car to get the maximum sunlight exposure during the winter with your front windshield facing east in the mornings and south in the afternoons - this maximizes the suns warming up your windshield so you dont have to put on the defroster. 4) If you can - drive during the warmest part of the day and avoid driving when its cold if you can. 5) Combine all trips less than 4 miles/20 minutes together during the day - driving each trip in sequence with the longest one first and the shortest one last making sure that the time between each trip is less than 15 minutes of the last. 6) Keep your speed under 53 mph, for best fuel efficiency keep your speed between 23 mph to 46 mph. Driving longer than 40 minutes per trip tends increases your fuel efficiency while driving less than 40 minutes per trip tends decrease your fuel efficiency. 7) keep your Prius trunk empty ( keep your payload as light as possible especially over the rear tires). 8) Avoid driving in wet/rainy, icy or snowy road conditions ADDITIONAL WORK REQUIRED ===================== 1) Raise your tire pressure to 42 psi front/ 40 psi rear. 2) block your lower air intake grill as a previous replying poster has suggested when the outside temperature is less than 50F. MAJOR INVESTMENT REQUIRED. ======================== 1) install Toyota's optional electric 400W engine block heater onto your Prius. Plug it into a wall socket for 30 minutes to 90 minutes before you drive. After it warms up your engine coolant, remove it and drive off. The Engine block heater cost about $60. The installation if professionally done is the major expense ($$$) but it can be done as a DIY if you have the time, energy, and skill ( a heated garage or a nice warm day in the parking lot helps). The ongoing electricity cost to heat up your engine and whether the FE savings is worth the cost is one of debate. From what I've read Engine block heater last from 3 to 6 year. 2) Learn to hypermile with a ScangaugeII. The ScangaugeII cost $160 normally but the bigger investment is in your time and effort. While hypermiling can achieve over 20% better fuel efficiency than the EPA, it usually requires that Prius must be driven slower than what most people are use to and adds about 25% more time to your travel time. For a second opinion/resource ======================= A Hybrid Owner’s winter survival guide - CleanMPG Forums FWIW: MPG improves over time because the stock Prius tires' rolling resistance will decrease over time - New tires cause a 5% to 10% reduction in MPG for the first few months. hope this helps Walter Lee (aka "HyperDrive 1" on Cleanmpg.com) 2010 Toyota Prius III , Blue Ribbon/Dark Grey, oem floormats Yokohama Avid S33D (front 50psi/rear 48psi) ScangaugeII(Fwt ,SoC, GPH, RPM) 100% grill blocking Odeometer +17800 miles overall 61 mpg Worst Tank 52mpg (Winter, Dec 27th 2010) Best Tank 70mpg (Fall, Sep 29th, 2011) Last tank (Dec 8th, 2011) 63 mpg, 17835miles, 636 miles using 10 gallons of E10 87oct gasoline.
Regarding #1, some people use windshield covers to avoid having to scrape ice. Having covered or garage parking helps too. When I had covered parking at my apartment, the car that was covered had a clear windshield while the other didn't, if it got to freezing outside. Regarding #5, yup, this is always a good practice in general... if going to the shortest destination first, stopping, then the next and so on, the ICE may never finish warming up and is constantly wasting fuel in warmup mode. Scangauge II athttp://www.amazon.com/dp/product/B000AAMY86?tag=priuschatcom-20 is now down $118. I posted about it in another thread but it was $118.85 yesterday.
Some of us can not avoid driving daily on ice / snow. When temps are minus, just get used to the idea that fuel economy will be less.
+ the winter survival guide, he did an excellent job. A Hybrid Owner’s winter survival guide - CleanMPG Forums
+1 You can do a lot to keep mpg's high in the freezing cold - but slush, rain, snow ... there's no way to prevent the drag that those elements cause. Those are mpg reducing things that can't be prevented. only the lower grill? Maybe for YOU that works, but when it comes to grill blocking that's not all that some do. In addition, a few of us got Toyota thermostats (from Japan) that run a few degrees warmer. That helps a bit too, along with all the other trick that have been posted ad infinitum. .
What is your average trip distance? Due to engine warmup needs, short trips are not good for MPG in any gasoline car. I live in your region but was out of town the first half of this month. As my MPG graph shows, past Decembers have produced the worst MPG. Summer will be much better. You are new to the Prius, so you still have a lot to learn. And if you were not already a hypermiler, you have even more to learn. Refer to the already-mentioned winter survival guides both here and on CleanMPG. For the very best results, you will also need a ScanGauge or other engine monitor, though this is overkill for most drivers.
wowsers! That's a bargin! My first one cost me $160. My second one (now on loan to a FEH with an intermittent ABS problem) cost me $125...I really do miss my second one... I am soo tempted to get a third....
what site did you go to to get the thermostat from Japan? And was it a coolant thermostat or a heater thermostat?
Coolant. One of the members here on PC brought a bunch over (from japan), many years ago, for the gen3 reveal in Detroit. Wow! That was a lot of years back ... just like this thread .
