DOES A TOYOTA PRIUS REALLY GET 50 MILES PER GALLON?

 

How many miles per gallon does a Prius get?  That is what I wondered when I was shopping for a car.  I had heard about how owners had claimed the Honda Civic Hybrid's gas mileage had been exaggerated and I wondered if the same applied to a Toyota Prius.   

Prius Gas Mileage

My old $1300 car needed a $1500 part so I decided to get rid of it.  I was shopping for a car and I was seriously considering buying a Toyota Prius.  I wondered about Prius MPG.  I had read about the lawsuit against Honda for claiming the Hybrid Civic got more MPG than it really did.  I wondered how much gas mileage the Prius really got.  I read about folks getting great gas mileage by overinflating the tires.  I had seen the obnoxious Prius "hyper-milers" holding up traffic doing 50 miles per hour on the interstate.  I had read articles claiming the Gen III models (beginning 2010) got better mileage than the earlier models.  The salesman promised me it really got 50 miles per gallon but I have an inherent mistrust of car salesmen.  So, I wondered...

In January of 2012,  I bought a two year old 2010 Prius II with 50,000 miles on it.  For the unitiated, that is a base level 3rd generation Prius with minimal gadgetry.  It has power windows and doors and that is about it. 

I wanted a Prius but I guess I bought it as much as anything just to find out if it really did get 50 miles per gallon.  The answer is:

 Yes, the Prius actually does get 50 MPG.

Nobody is ever going successfully sue Toyota Motor Corp. for falsely claiming the Gen III Prius gets 50 miles per gallon.  It gets 50 MPG with ease and if you try, you can get more.  In fact, you have to drive it a very certain way to avoid getting 50 miles per gallon.  Here's the deal. 

The Prius gets relatively poor mileage until the engine warms up.  This takes about five or six miles.  During this warmup time, it gets about 35 to 40 miles per gallon.  If your driving consists of purely short, say five mile, trips - you will not get 50 miles per gallon.

You can also get less than 50 miles per gallon by driving very fast.  In my experience, if you average over 73 miles per hour, you can push the gas mileage below 50 miles per gallon.

Obviously, if you drive very aggressively the mileage will also suffer.

I live in a flat area and I assume that driving in a hilly area could also cause you to get less than 50 miles per gallon.  I don't know.  The car captures a significant amount of energy through regenerative braking but I can't imagine how it could fully compensate for the extra energy required to climb hills.

The Prius, like most vehicles these days, has a display that tells you exactly how many MPG you are getting, both at the moment as well as historically.  It is a bit optomistic in that it overstates gas mileage by about 4% but it is otherwise fairly accurate.  All of the gas mileage figures in chart below the graph are based on the display are corrected for this innacuracy.  Most of the gas mileage figures on this page are calculated though odometer mileage and gallons purchased but the ones based on the display are already adjusted downward 4% to compensate for this anomaly.

I kept track of the gas mileage beginning in January of 2012 and the results appear in the chart below:

 

PRIUS MPG: Overall, I'm averaging 50.73 miles per gallon.

Funny thing though - When I bought the car, it had Firestone Fuel Saver Tires on it.  They needed to be replaced.  After researching tires, I put on a set of Michelen Energy Saver A/S tires.  I was guided primarily by this article:  http://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=121

A very interesting phenomenom occured.  I expected my gas mileage to go up significantly.  It did not.  It took me a while to figure out what happened.  I guess it occured subconsciously.  The Firestone Fuel Saver tires were noisy.  It bothered me initially and then I kind of got used to it.  After I got the Michelin Energy Saver tires, the vehicle's cabin was quieter.  Significantly quieter.  I started driving faster.  Driving was more enjoyable.  My faster driving accounts for the lack of improvement in MPG.  The chart below details the Prius MPG at various speeds and as you can see, the Michelin Energy Saver tires did help fuel economy.

SPEED Firestone Fuel Savers Michelin Energy Saver A/S
     
45 MPH 68 MPG 67 MPG
50 MPH 66 MPG 62 MPG
55 MPH 64 MPG 70 MPG
60 MPH 55 MPG 56 MPG
65 MPH 53 MPG 56 MPG
70 MPH 47 MPG 52 MPG
73 MPH 46 MPG 49 MPG
75 MPH 43 MPG 46 MPG

By the way, all of the mileage figures were obtained with recommended inflation in the tires - 37 lbs front and 35 lbs rear.  The Toyota dealership where I get it serviced puts nitrogen in the tires and then when I check them - if they are low, I mix air with it.  I'm not sure if the nitrogen helps or not.  I can't imagine how it makes any difference.

In March, 2013 the dealership said they wanted to do a "Fuel Rail Service."  It sounded like a bunch of crap to me but the MPG had slipped a bit so I let them do it.  The MPG improved back up to the 50 level.  Then in July, 2013, I noticed the MPG slipping again.  I had a phillips head screw in a tire and it was leaking.  I replaced the tire and MPG improved slightly again!  The take-away, I think, is the Prius will get 50 MPG when everything is right.  If anything gets a little out of whack, it shows up quickly in gas mileage results.

INTERSTATE DRIVING:  Driving on the interstate, I generally go about 70 to 72 miles per hour.  This routinely nets 49 to 51 MPG.

The most gas mileage I have gotten is 80 MPG.  This was on a six mile trip that I was able to go a steady 35 miles per hour almost the whole way.  Also, 80 MPG was what the display showed so I guess it should be reduced 4%.  I am not one of those hyper-miler fools who go 45 miles per hour on the interstate in their Prius and I can't stand those who do.  I just drive it.

LIFETIME WARRANTY:  Toyota offers a lifetime warranty on many critical parts, including the CVT.  You just have to get it serviced every 5000 miles.  It is a bit of a pain to regularly run the 40 miles up to the dealership, but if someday I have to replace the CVT, it is easily worth it.

BRAKES:  Overall, I like the car a lot.  It is extremely reliable and incredibly cheap to operate.  I get asked quite a bit about what it is like to drive.  It is pretty much like any other car.  It has adequate power, but is no speedster.  The brakes are the only thing that is a little different.  When you first press on the brake, the regenerative braking is engaged.  It essentially turns the electric motor into a generator.  As you brake harder, conventional friction based brakes are engaged.  It is two stage braking.  Other than that, it drives like any other car.

CVT: The continiously variable transmission is nice.  There is not a noticible shift as you speed up from a stop.  The transmission just magically changes the gear ratio to what is needed at the time.  I really like it.

BACK WINDOWS: The back windows are geniunely weird.  Rear visibility is mediocre.  Nobody ever rides in my back seat so I removed the rear headrests because they parially obstructed the view out the back.  The window shapes were apparently dictated by the shape of the car. 

CAMERA:  I added a rear view camera to mine and it helps a little when  backing up.  I got mine at the Toyota dealership and it was grossly overpriced ($1,000) and has a tiny display that comes on in reverse in the left side of the rear view mirror.  If you are looking for one, I'd recommend seeking out some other, more competitive, source.

REVERSE BEEPER: On the subject of reverse, the Prius has a beeper that starts beeping when you shift into reverse.  Yes, just like a Catapillar bulldozer.  It is genuinely obnoxious.  My local Toyota Dealership, Eastern Shore Toyota in Daphne, Alabama, soaked me for $105 to disable it.  A ten minute job.  It is a simple setting they change by connecting a laptop computer to the car.  Some dealerships do it for free incident to an oil change.  If you buy one, be sure and insist the dealership disable it before you accept the car.

SEATBELT BEEPER:  When you don't buckle up your seatbelt a beeper starts beeping.  OK, I can live with that.   Here is the problem:  When you unbuckle your seatbelt and the car is going over 11 MPH, it starts beeping.  That is obnoxious.  For example, you pull into McDonalds and you unbuckle your seatbelt before you slow to 11 MPH.  The beeper beeps so loud you can hardly make your order at the drive in window.  This is a steady irritant that the dealership said they can not fix.  I can't find the beeper itself in the dash so, the beep goes on...

CONCLUSION:  If you get a Prius, nobody is ever going to tell you what a pretty car you have.  The car was designed in a wind tunnel and it looks like it.  Take a look at the Honda Insight that was also designed in a wind tunnel.  It looks like the same car.  I've had folks tell me it looks attractive but it just looks "different" to me.  Originally, I thought Prius' were genuinely ugly.  Now, I don't mind it.  I guess the best thing I can say about the appearance is that you get used to it.  Then, the first time you check your gas mileage, the appearance really grows on you...

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