1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Are people really getting 40+ MPG in Gen 2?

Discussion in 'Gen 2 Prius Fuel Economy' started by timmyjane, Apr 12, 2017.

  1. fuzzy1

    fuzzy1 Senior Member

    Joined:
    Feb 26, 2009
    17,035
    10,010
    90
    Location:
    Western Washington
    Vehicle:
    Other Hybrid
    Model:
    N/A
    External racks are simply incompatible with high MPG and hypermiling, in any car. Either lose it, or reduce you expectations.

    The fast lane is also not conducive to average or better MPG on any car model.
     
    jerrymildred and srellim234 like this.
  2. Kaptainkid1

    Kaptainkid1 Active Member

    Joined:
    Mar 13, 2019
    307
    242
    0
    Location:
    Los Angeles
    Vehicle:
    2009 Prius
    Model:
    III
    I think you might got my Roof Rack mistaken for a Roof Rack with a box. I run the thule box when I go on long trips and need extra space. I also expect to lose miles when running a box. Otherwise I leave my roof rack on the car all the time. I assume the drag created by racks are minor maybe 3mpg loss at best. Why do people think the racks are like sails. (Jerrymildred).
    20190314_142703.jpg

    20190314_142638.jpg Prius.jpg
     
  3. mpg_numbers_guy

    Joined:
    Jan 20, 2019
    116
    64
    0
    Location:
    VA
    Vehicle:
    2013 Prius c
    Model:
    Two
    New tires will also reduce your MPG some until they "break in".
     
  4. fuzzy1

    fuzzy1 Senior Member

    Joined:
    Feb 26, 2009
    17,035
    10,010
    90
    Location:
    Western Washington
    Vehicle:
    Other Hybrid
    Model:
    N/A
    Don't assume it, test it.

    Even on my old gas hog Subaru, when gas prices spiked, I took to removing the factory crossbars when unused. Your non-factory towers look worse. If your crossbars are round instead of airfoil shaped, then they are worse too.

    Experience on prior cars.
     
    jerrymildred likes this.
  5. jerrymildred

    jerrymildred Senior Member

    Joined:
    Oct 28, 2016
    11,490
    14,095
    0
    Location:
    Tampa, FL
    Vehicle:
    2017 Prius
    Model:
    Two
    I agree with @fuzzy1. It's not just the frontal area of the crossbars. It also the way they dirty up the airflow over the top and rear of the car. That reduces increases the coefficient of drag for the whole area.

    edit: OOPS!! That was a dumb typo. Thanks, @fuzzy1. Somehow, proofreading my own typing doesn't always help. :oops:
     
    #225 jerrymildred, Mar 14, 2019
    Last edited: Mar 15, 2019
    fuzzy1 likes this.
  6. fuzzy1

    fuzzy1 Senior Member

    Joined:
    Feb 26, 2009
    17,035
    10,010
    90
    Location:
    Western Washington
    Vehicle:
    Other Hybrid
    Model:
    N/A
    ... increases ...
     
    jerrymildred likes this.
  7. ericbecky

    ericbecky Hybrid Battery Hero

    Joined:
    Mar 12, 2004
    4,365
    3,209
    1
    Location:
    Madison, Wisconsin
    Vehicle:
    2005 Prius
    Model:
    Two
    Of you remove the rack and drive exactly like the EPA test in conditions that are the same as the EPA test, you will get the EPA rated mpg.

    Roof rack and interstate speed (or higher) will certainly kill mpg. I'm talking about roof rack with nothing on it.

    Take it off, drive at highway (not interstate) speed, you will see what the car is capable of.

    You said you keep tires properly inflated. That's good. Any idea if you have stock, low rolling resistance tires on it. (Sorry if I missed it in the discussion.)
     
  8. Kaptainkid1

    Kaptainkid1 Active Member

    Joined:
    Mar 13, 2019
    307
    242
    0
    Location:
    Los Angeles
    Vehicle:
    2009 Prius
    Model:
    III
    I'm running Hankook Optimo H727 which are all season tires and they are not LRR tires but I've read they have good reviews. Also I'll pull off the Racks and see if I would get better MPG. So far after resetting my mpg avg on the MFD and hypered mile all day driving I've noticed my mpg went up to 42mpg. Not the type of driving I like to do in the city. I'm the A-hole Prius driver holding the traffic because I'm trying to only accelerate using only my slow electric motor. Now I know why Prius drivers suck because car is designed to encourage crappy drivers. Lol.
     
  9. Devdas

    Devdas Member

    Joined:
    Jan 31, 2019
    135
    169
    0
    Location:
    London
    Vehicle:
    2008 Prius
    Model:
    ----UK----
    My gen 2 Prius averages between 50/55 mix use motorway driving and city driving it has 130,000 miles on the clock regular maintenance
     
  10. jerrymildred

    jerrymildred Senior Member

    Joined:
    Oct 28, 2016
    11,490
    14,095
    0
    Location:
    Tampa, FL
    Vehicle:
    2017 Prius
    Model:
    Two
    That'll really kill your gas mileage! If you run down the battery like that, then the car has to recharge the battery more than it normally would and there is always energy lost in that process.

    I've read that the most efficient rpm would be where your mpg number is between 50% and 100% of the speedometer. ie: 15-30 mpg at 30 mph as you're accelerating. That seems to be true for our gen 2. It's still slower than traffic wants to go, though.
     
    Kaptainkid1, Raytheeagle and dolj like this.
  11. dolj

    dolj Senior Member

    Joined:
    May 14, 2012
    7,447
    3,751
    0
    Location:
    Wellington, New Zealand
    Vehicle:
    2007 Prius
    Model:
    N/A
    +1 to the above advice from @jerrymildred. I was about to say something very similar.

    The car was not designed to be driven in the way you described and as Jerry said, you will actually hurt your MPG (as you have demonstrated). You would be better off just driving normally, as that is how the car is designed to be driven, no need to be the A-hole.

    My current tank is sitting on 59 MPG (71 MPG (UK)) and I do not drive slow. It was at 62 MPG (74 MPG (UK)) earlier, but then I had to do some hills! By the end go the tank it will probably settle around 53 - 56 MPG.

    Get up to speed quickly – 20 MPG (slow) - 11 MPG (faster) on the Energy Screen, and engage the ICE, do not try and use electric.

    The best hypermiling technique is Pulse and Glide. Again, get up to the speed of the traffic and then pulse to 33 MPH. Glide down to 29 MPH. Rinse and repeat. Adjust the numbers to work in with the traffic around you. You will find this works remarkably well and is easy to do in an urban environment as most people can't maintain a constant speed.

    Second hypermiling technique is anticipation, both slowing down and accelerating.

    You will know when you're doing it right because the battery graphic on the Energy Monitor screen will be at 6 - 7 bars a lot.

    Hope that helps.
     
  12. jerrymildred

    jerrymildred Senior Member

    Joined:
    Oct 28, 2016
    11,490
    14,095
    0
    Location:
    Tampa, FL
    Vehicle:
    2017 Prius
    Model:
    Two
    Hard stops seem to me to be as bad as hard acceleration for gas mileage, too. That gliding and/or regenerating as you approach the queue of cars or the light makes a huge difference. And then you get to use the energy you stored regenerating rather than having thrown it all away in heat and brake pad dust.
     
  13. fuzzy1

    fuzzy1 Senior Member

    Joined:
    Feb 26, 2009
    17,035
    10,010
    90
    Location:
    Western Washington
    Vehicle:
    Other Hybrid
    Model:
    N/A
    On top of that lost regeneration from hard stops, there is also the extra fuel burned earlier to maintain speed, or even to produce extra speed, when one could have been gradually gliding down fuel-free to the impending stop.

    Hard stops are also commonly associated with lost timed-light opportunities, where early slowing or gliding can mean saving some speed and kinetic energy by avoiding needing to stop altogether.
    This is less beneficial than many drivers realize. The savings from proper gliding to stops is much greater. And above about 15 mph, this electric-only acceleration actually works against you, not for you. So don't be an A-hole, get your fuel savings elsewhere.
     
    Kaptainkid1 and jerrymildred like this.
  14. VFerdman

    VFerdman Senior Member

    Joined:
    Jul 5, 2017
    1,148
    1,171
    3
    Location:
    Western Massachusetts
    Vehicle:
    2007 Prius
    Model:
    Three
    I noticed that you are from UK, so I have to clarify. When you state 50/55, I assume it's MPIG, that is Miles Per Imperial Gallon. Please clarify the units for us as it make s a big difference. It took me a while to understand why our fellow Prius drivers from UK are getting so much better gas mileage. Then I realized you guys are using Imperial Gallons, which are larger than US gallons (Why?!!!! Let's just all use metric!). If I am correct in assuming your gallons are imperial, then your numbers should be divided by 1.2 to make sense to US readers. 50/55 then becomes 41.7/45.8, which makes a lot more sense and is pretty much normal healthy Gen 2 fuel economy.
     
    Data Daedalus and srellim234 like this.
  15. Zeppo Shanski

    Zeppo Shanski Active Member

    Joined:
    Feb 5, 2019
    282
    150
    0
    Location:
    Chicagoland
    Vehicle:
    2005 Prius
    Model:
    Base
    I've got 3 pips on my gas guage. I made a mistake this morning and saw my mpg consumption. I'm running @ 49.8 mpg. I wanted to wait until it got to 1 pip ... but now LOL ... I don't want to lose that 49.8 mpg. I guess I'm just gonna keep driving nice.




    2005 w/ +/-143,000 miles.​
     
  16. srellim234

    srellim234 Senior Member

    Joined:
    Jun 26, 2015
    1,192
    1,680
    0
    Location:
    Laughlin, Nevada
    Vehicle:
    2008 Prius
    Model:
    Touring
    That's correct.

    Fuelly.com has the 2008 Prius averaging 42.9 Mpg or 51.6 "UK MPG" with entries from 587 vehicles over 16.7+ million miles. That means that for every 50 mpg U.S. car there are three others getting 40 or less.The four 2008 Prii still being reported at fueleconomy.gov are at 40.6, 42.9, 45.7 and 45.9 U.S. mpg, respectively.

    Kaptainkid1, for not having LRR tires, your acceleration technique and dragging an empty roof rack you're probably right where you should be with regards to your fuel consumption.
     
    Data Daedalus and Kaptainkid1 like this.
  17. George W

    George W Active Member

    Joined:
    Mar 12, 2018
    909
    510
    1
    Location:
    San Antonio
    Vehicle:
    2008 Prius
    Model:
    Touring
    Many members of The Forum over inflate their tires just a tad. 42 front and 40 rear seem to be a good combination for most generation 2 drivers
     
  18. Data Daedalus

    Data Daedalus Senior Member

    Joined:
    Jul 6, 2013
    1,022
    1,182
    0
    Location:
    Wembley, London
    Vehicle:
    2008 Prius
    Model:
    II
    I believe I’m on 39 Front and 37 rear at the moment. These pressures on a tyre good to 51psi seem a good balance between firmness and a bit of shock absorbing bounce.

    Best thing is, I’m presently staring at 61.5mpg (UK) on the MFD, and I’m NOT holding up the traffic at all; yes I’m hypermiling but either keeping up with the traffic or actually passing it. How?

    My commute takes me through a prolonged speed cam zone on London’s A406. It has both 40mph and 50mph zones.

    I transverse these zones at 40 or 50mph GPS speed. That equates to 44mph or 54mph on my speedometer.
    The grand majority of other motorists watching their speedometers are travelling slower. Ergo, I’m always passing most of them.
    I’m also achieving the aforementioned mpg by utilising Cruise Control while in the average speed cam zones, and often have the AC on too!

    I get up to speed quickly during my morning commute then kick in cruise control. My cheat is driving to work between 5.30am and 6.00am for a 6.00am start. Empty roads and little traffic.
    It’s a big difference between a 30 minute cruise to work, and a 90 minute crawl in congested traffic.

    The return journey is with traffic, but takes 45 minutes as I leave for home before everyone else does. That contributes to my great mpg figures.

    I don’t drive like a snail, keep up comfortably with the traffic, anticipate what lane to follow well in advance, exploit hills to the maximum, regenerate to a halt every time.
    And I let The Spaceship do all the hard work by utilising CC where possible and avoiding using EV unless I’m in a small traffic jam, where it comes in very handy till you’re past the traffic lights
     
    Raytheeagle likes this.
  19. Data Daedalus

    Data Daedalus Senior Member

    Joined:
    Jul 6, 2013
    1,022
    1,182
    0
    Location:
    Wembley, London
    Vehicle:
    2008 Prius
    Model:
    II
    Here’s my mpg on 1st April when it warmed up a tad in London UK.
     

    Attached Files:

    jerrymildred and Raytheeagle like this.
  20. Zeppo Shanski

    Zeppo Shanski Active Member

    Joined:
    Feb 5, 2019
    282
    150
    0
    Location:
    Chicagoland
    Vehicle:
    2005 Prius
    Model:
    Base
    Vehicle/mileage ... 2005 Gen-2 ... 145+,000 miles.

    Last tank ... 51-mpg.

    Tires ... std. inflation.

    Driving style ... Regular 57-yo guy w/ NO attitude.