Cannot find answer - 2 questions

The over-stated MPG calculation (compared to manual calculation dividing miles driven by gas used) has been well documented in this forum, so your car is not unique.

Regarding your MPG vs. the EPA rating of 50, a few comments. Winter driving lowers MPG for a variety of reasons. If your driving involves relatively short trips, that hurts MPG. Are you driving in ECO mode? MY experience is that helps by a few MPG. If you drive in a hilly area, that's also a negative. It also takes a while for the car to break in and this also negatively affects MPG.

I just passed 20K miles, and have lifetime average of ~45 MPG. I've never driven a car that got the EPA rated MPG, so getting ~10% less isn't surprising (actually it's a bit less than that, isn't it, given the over-stated MPG calculation?).

 

There may be something wrong with your car. Make an appointment, take your car to the dealer, it is under warranty. Make sure you tell them that the MPG is not at the EPA rating. They will take care of it for you. Then report back to us.

 

Hi.

I have a 2010 Prius with 20,000 km and my average is 42 mpg (US gal). It's really 50 mpg (Cdn Gal) using the imperial gal, as we use in Canada, but converted to US gallon it's 42 mpg. However, I don't expect much more than that since I take short trips (15 min driving), live in an hilly area, temp is around freezing this time of the year. On the other side, I do have my tires inflated to 36 psi and I do practise pulse and glide, even though it's less than optimal due to all the hills. I don't see much of an increase in the summer months, but I think the other negatives as I mentioned influences that.

Compared to a Corolla, driven in the same area, I am getting the same percentage of the EPA rating (around 84%) so I guess that's reasonable for the Prius.

The speed limit around town is 50 km/hr. I find that the pulse and glide doesn't work too great for me at that speed, given the hills. My feeling is that at that speed the ICE wants to run more. I've tried P&G at around 35-40 km and the ICE doesn't run so much but that's too slow for the traffic around here.

A final note, the 60 mpg (US gal) reported by Prius owners on this site really blows me away. I can't understand how people are doing that. Every factor must be in their favour. The only question I have is how fast are these people driving around town?

Dennis

 

Avoid using the cabin heater, fill the tires to 44/42 PSI front/rear, never use "B", don't warm up the car before driving. Note that 50 MPG = 2.00 gallons per 100 miles, and 48 MPG = 2.08 gallons per 100 miles.

The MPG meter *is* actual. Miles driven divided by gallons pumped is nearly meaningless for a single tank.

 

All the reasons already stated could be reasons your MPG's are "slightly" lower. Many area's have winter fuel blends that can be detrimental to MPG's.

Also, your car is basically brand new. I'd actually expect MPG's to improve as the engine breaks in, and as the tires wear....less rolling resistance.

I bought a new car last year (not a Prius) but I saw my MPG's improve significantly after the 1st Oil Change and around the 6000-8000 mile range.

You could always have the dealership check it out. To relieve any worries you might have, but my speculation will be with a vehicle less than 3 months old, showing no codes, they will simply tell you everything is "normal".

43.5...in the winter, on a vehicle (Prius) still being broken in? Doesn't sound out of the range of normal to me.

 

There are a lot of factors that go into getting the EPA rated mileage or better. I have always gotten better than the EPA ratings in all of my cars. It is just a matter of how much weight is in the car, and how aggresive you are driving it. I have found that fully loaded (close to the Prius' maximum 800lb weight limit) means that you will get less than the EPA rated mileage unless you are going downhill. Also getting the 50mpg requires you driving part of the time in electric mode. I am very fortunate to live where I do as the road to my work is very conductive to Prius. By the time I am done with the cars warm up I am able to hit the 35mph section, drain the battery. It goes back up to 45mph and I recharge the battery, and then it goes back down to 35mph. Then I recharge it the whole rest of the way to base where I exclusively use the battery to finish my drive to work. This yields the 60mpg average you speak of. Other than that I usually try to break even at the 50mpg, but utilizing highways and stuff like that is going to drag you down below the 50 mark.. I have noticed a lot it also depends on wind direction, speed, and the outside air temperature. So far though after almost 2600 miles I cannot complain. My old car only got 15mpg in town, so this is a vast improvement. Just need to find the route, and driving style that works for your car.

 

I'm in OKC just down the turnpike from you. I filled up just an hour ago and achieved very good mileage. The hand calculation was 63.9 but the HSI showed 67.6 mpg. That difference is not abnormal for this car. It's also been discussed at length on this forum. As you know our winds have been extremely high as of late even though the temps have been almost hot. The 20-40 mph wind is a killer if you have to drive into it at highway speeds. Also, if your commute is just a few miles that will also kill your mileage because your engine is not getting warmed up. I know parts of Tulsa have quite steep hills and those are also big mpg killers. Without any real details about your specific driving environment, this is very hard to diagnose.

Try to give us a detailed description of your daily commute. Example: I live at the bottom of a hill and my commute is x miles long and it's 75 mph for x miles in PWR mode or ECO mode or it's stop and go traffic or, etc. You get the idea.

 

Nice looking car. You're a very young looking driver.

 

I like your pinstripe did you have it put on or buy your car with it on already? Is it a single line or a classic thin pair stripe?

Aloha,

ED

 

I agree that a description of your commute would help, down to the terrain, distances, and speed limits. My gen3 also has roughly 4000 miles on it and I am currently at 60 mpg on the readout for the tank, my best ever. The commute includes a highway stretch at 55 mph as well as city traffic at 40.

also, see the sticky for questions relating to fuel economy.

 

First, there is no 'promise' of 50 mpg. That is the output figure of a standardized government test and calculation. Your mileage will (not may) vary.

Don't expect your dealership to be very helpful. When my old Subaru feel far short of its EPA label, the dealer offered only a bunch of lame reasons that did not apply to my situation. Only years later after discovering CleanMPG.com did I learn the real reasons and start beating its EPA rating.

To give us a better framework to address your MPG problems, please read and answer Cwerdna's questions here: Fuel economy complaints/queries? Please copy, paste & answer these questions ... Please post the answers to this thread, not over there.

 

65% is a lot of highway, what speed do average? that can kill your mileage. stay opff the highway for a tank and see what happens.

 

There's another option you can try. Find a place where you can drive between 35 -45 mph for several miles and has little to no traffic and is relatively flat. Switch to trip B and reset it to zero. Now drive 10 - 12 miles in ECO mode and tell us the consolidated mpg results for just that run. With this high wind, an East/West route is what you want. The point is to see what "you" can get under optimum conditions in your car.

 

^^ I'll rephrase Mark's advice as "let's see what the car does MPG wise when the driver is removed as a variable." Wind is a big deal, wait for a calm day for the test.

By the way, the EPA really does not 'promise' anything to any one driver. The '50 mpg' is the middle of a range that includes most drivers. Most owners end up above or below the exact middle. If you want to be in the other group then slow down and use the brakes less.

 

Around the end of March they switched back to summer formulated gasoline from the winter formulation and that will always give you a little mpg boost. The Prius almost always (it varies) has a 2 - 3% variance in the estimated consolidated mpg versus the hand calculated mpg. It has to do with how often the vehicle samples the fuel flow and other factors. My previous 4Runners were also pretty bad at their estimate as well. My wife's 05 Altima is usually within 0.5 mpg of the estimate. It's just one of those things, and every vehicle will be different. I know it exists and I file that away and go on and smile as I pass gas stations.