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

Mod ideas for increased mileage

Discussion in 'Gen 2 Prius Accessories & Modifications' started by oh-no, Oct 4, 2014.

  1. oh-no

    oh-no New Member

    Joined:
    Sep 18, 2014
    13
    1
    0
    Location:
    Ohio
    Vehicle:
    2004 Prius
    Model:
    II
    has anyone documented modifications for increased mileage; save the LRR tires?

    years ago, on the bimmer forums, there was a member that documented mpg's in his e30 by trying different mods such as removing his side mirrors (which i recall gaining him 3-4 mpg).

    "DTM" style mirrors were cool a few years ago and i was thinking about fitting some to the '04 to reduce drag. you can easily google image search for the mirrors in question (i do not yet have the privilege to post links). the mirrors are small radius and tucked tightly against the car.

    of course i realize an e30 and a prius are drastically different but it seems the areo principles would remain the same; big mirrors = more resistance/drag.
     
  2. M in KC

    M in KC Active Member

    Joined:
    Jun 21, 2014
    358
    106
    0
    Location:
    KC, MO
    Vehicle:
    2005 Prius
    Google hyper miling. There are several websites that speak to this but not a lot of imperial data to support each mod just theoretical gains. LRR tires, ebh and some form of grill blocking for us in the snow belt seem to be the most quantifable in the risk/reward proposition.
     
    oh-no likes this.
  3. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    107,796
    48,995
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    there was one guy, awhile back, who was gonna remove the entire interior of his car. strip every ounce of weight possible. never heard from him again.
     
  4. wjtracy

    wjtracy Senior Member

    Joined:
    Sep 19, 2006
    11,314
    3,588
    1
    Location:
    Northern VA (NoVA)
    Vehicle:
    Other Hybrid
    Model:
    N/A
    Maybe I take a shot at an outline:

    Pushing MPG to the MAX
    A. Car mods (Engine block heater, Blocking Grills, insulate engine comparment (eg; EFusco), maybe aerodynamics (license plate etc...) also, thermistor electronic hack, wax car(?)
    B. Tires (LRR type, higher pressure...) (fill with N2 - just slows down leakage loss by ~25%)
    C. Fuel (higher energy content: E0, non-RFG, possible energy content variations between grades in some non-RFG areas)
    D. Driving techniques (warm-up, hyper miling, avoid short trips, etc)
    E. Lubes (lower viscosity 0W-20 etc)

    The most important in winter is the cold engine, so the grill blocks etc.
    Some hypermilers really go to high tire pressures but I do not know.
     
    #4 wjtracy, Oct 5, 2014
    Last edited: Oct 5, 2014
    oh-no likes this.
  5. Easy Rider 2

    Easy Rider 2 Senior Member

    Joined:
    Aug 5, 2014
    1,584
    257
    0
    Location:
    Ocala, FL
    Vehicle:
    2013 Prius c
    Model:
    Three
    A multi-billion dollar company has designed a car for the highest mileage that they can......within practical limits and legal requirements.

    Any time you hear that somebody claims a simple and cheap "modification" will significantly increase the fuel efficiency even more........you should send the price of that gadget to ME. The increase you experience will be just the same; maybe even more. ;)
     
    krmcg likes this.
  6. oh-no

    oh-no New Member

    Joined:
    Sep 18, 2014
    13
    1
    0
    Location:
    Ohio
    Vehicle:
    2004 Prius
    Model:
    II
    no one mentioned gimmicks. the mirrors i mentioned would not be social acceptable for toyota as they would have further alienated the buying population; most people think its a pretty ugly car already.

    my car did not come with rear wheel skirts; are you suggesting that rear skirts would not decrease drag and improve mpg?
     
  7. Easy Rider 2

    Easy Rider 2 Senior Member

    Joined:
    Aug 5, 2014
    1,584
    257
    0
    Location:
    Ocala, FL
    Vehicle:
    2013 Prius c
    Model:
    Three
    I don't know because I don't have a wind tunnel to test.
    I suspect that other subtle changes to the body contours will do much the same thing.
    I also suspect that it would not make a significant difference or SOME company would offer it.
     
  8. bestmapman

    bestmapman 04, 07 ,08, 09, 10, 16, 21 Prime

    Joined:
    Apr 8, 2007
    1,289
    242
    3
    Location:
    Kentucky near Cincinnati, OH
    Vehicle:
    2021 Prius Prime
    Model:
    Limited
    There is one modification that really works. This modification is guaranteed to improve you mileage.

    It is you.

    The modification of your driving habits will show the biggest increase you fuel economy.
     
    Uncle Dave, Sam Brinson and sidecar like this.
  9. wjtracy

    wjtracy Senior Member

    Joined:
    Sep 19, 2006
    11,314
    3,588
    1
    Location:
    Northern VA (NoVA)
    Vehicle:
    Other Hybrid
    Model:
    N/A
    We don't really have too many mods for better MPG except a whole bunch of heat management stuff as I mentioned above. The biggest MPG loss we have is the first 5-10 minutes warm-up cycle. I have the theory the severe warm-up MPG loss is due to the fact that all U.S. Prii are CARB certified. There is has been some discussion/speculation that FORD hybrid models for non-CARB states may not show as much MPG loss in the first five minutes as we see in a Prius. (Note that the fact that Prii are CARB certified does not mean all Prii get the extended warranty - rather Toyota has policy rules to say who qualifies.)

    There have been a few threads on aerodynamics/mirrors /etc. but not too many. It would be good to try to remember those, if anyone can.

    Lots of threads on the various "snake oil" mods (not specific to Prius) but no one is believing those. These are things like feeding H2, water etc.

    One mod I neglected to mention above is car weight, which gets some discussion. You can remove spare tire and some stuff. In my wife's case she kicks me out and gets another 1 MPG at least.
     
    Data Daedalus and oh-no like this.
  10. m.wynn

    m.wynn Senior Member

    Joined:
    Oct 24, 2013
    684
    1,226
    0
    Location:
    Queensbury, NY
    Vehicle:
    2014 Prius
    Model:
    Three

    Winston Chin's ECT Spoofer - A Prius ECT Spoofer MCU Controlled | PriusChat - is both low-dollar and legit.
     
    #10 m.wynn, Oct 7, 2014
    Last edited: Oct 7, 2014
    oh-no likes this.
  11. SageBrush

    SageBrush Senior Member

    Joined:
    Jun 4, 2008
    11,627
    2,530
    8
    Location:
    Southwest Colorado
    Vehicle:
    2012 Prius v wagon
    Model:
    Two
    The Aero principle is actually Cd(a)*Area

    Meaning don't bother with the Prius mirrors.
     
    oh-no likes this.
  12. usnavystgc

    usnavystgc Die Hard DIYer and Ebike enthusiast.

    Joined:
    Jul 29, 2011
    3,159
    988
    0
    Location:
    Tucson, AZ
    Vehicle:
    2005 Prius
    Model:
    Four
    Hi oh no,
    Welcome to PC. There is a forum called ecomodder.com. Those guys are serious and yes there mods will work on a Prius or any car.

    I was at the air show in Osh Kosh WI this year and saw a guy who seriously aeromodded his Prius. He removed the mirrors and deleted the windshield wipers, put pizza pans on the front wheels and skirts on the rear, full underbody was slick and grill blocking upfront. He claimed a 54mpg average on the highway since the mods (which is a +9mpg or 20% increase over EPA). Of course aeromods only provide a significant improvement in hwy mileage and top speed. So a lot of city driving makes the aeromods virtually useless.

    Here's a thread of a guy that did some pretty serious aeromods
    3rd gen Prius aeromod thread - Page 3 - Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com

    There's a guy that did a full boat tail on a Prius but, I can't find it.

    Now for city driving, Winston's (ccdisce) temp spoofer will help the first 5 minutes but, the neg is you heater will not work as well with it on.
     
    oh-no likes this.
  13. oh-no

    oh-no New Member

    Joined:
    Sep 18, 2014
    13
    1
    0
    Location:
    Ohio
    Vehicle:
    2004 Prius
    Model:
    II
    id like to do the EV button and possibly the spoof. both seem like good answers to short trips, the driveway shuffle and the morning commute.

    extreme mods are really fun to read.
     
  14. usnavystgc

    usnavystgc Die Hard DIYer and Ebike enthusiast.

    Joined:
    Jul 29, 2011
    3,159
    988
    0
    Location:
    Tucson, AZ
    Vehicle:
    2005 Prius
    Model:
    Four
    Here's what I would like for my Prius to look like ( with a full slick underbelly of course)

    The EV button is absolutely useless. Don't even waste your time. Now, I could see getting one of the grid chargers from PC shop and running your battery down as low as you can on the way home, charging it at night with the grid charger (resulting in a full charge the next morning). But, you wouldn't want to charge to 100% every night. Just 70-80%.
     

    Attached Files:

    #14 usnavystgc, Oct 7, 2014
    Last edited by a moderator: Oct 7, 2014
    oh-no likes this.
  15. oh-no

    oh-no New Member

    Joined:
    Sep 18, 2014
    13
    1
    0
    Location:
    Ohio
    Vehicle:
    2004 Prius
    Model:
    II
    i figured the EV mode would help with low speed cruising especially in winter when the engine needs to run more often to keep temp. i'm finding that, even after the engine is warm and i am well into my drive, that it can be difficult to coast on just the batteries. the engine will kick on and i cant find the sweet spot on the throttle.

    i changed my route to work considerably to get better mileage and much of it is hilly 35 mph so theres lots of opportunity for downhill braking/charging. but with the touchy throttle positioning i was hoping EV mode would allow me to use less gas motor.
     
  16. usnavystgc

    usnavystgc Die Hard DIYer and Ebike enthusiast.

    Joined:
    Jul 29, 2011
    3,159
    988
    0
    Location:
    Tucson, AZ
    Vehicle:
    2005 Prius
    Model:
    Four
    The EV mode will not help with that but, knowing these stages will. When you can't find the "sweet" spot, you are in stage 3b. You need to get to stage 4. You do this by coming to a complete stop, with the ICE running for 7 seconds after the ICE is warmed up. If when you come to a stop and the ICE is not running, and you haven't executed the "idle dance" to mode 4, you can force it to start by holding the brake down and giving it gas until it starts.

    Read this and become familiar with it.
     

    Attached Files:

    oh-no likes this.
  17. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,723
    38,252
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Set your display to show Hybrid System Indicator screen. If the car's warmed, and you lift off the gas then gently re-apply while keeping the bar display to the left of the median (highlighted in yellow), you should stay in electric:

    Capture.JPG

    Note, running in electric-only is one component of good mpg. But I wouldn't pursue it too aggressively, it becomes counterproductive if you run the battery down too much. Especially when the bar is nearly to the median, it eats the charge. Best to do that for short bursts only.
     
    oh-no likes this.
  18. usnavystgc

    usnavystgc Die Hard DIYer and Ebike enthusiast.

    Joined:
    Jul 29, 2011
    3,159
    988
    0
    Location:
    Tucson, AZ
    Vehicle:
    2005 Prius
    Model:
    Four
    He has a Gen II so that display doesn't apply and the operation of the software is also different.
     
  19. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    107,796
    48,995
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    the thing about highway improvements doesn't mean much without speed, grade and conditions.
     
  20. dolj

    dolj Senior Member

    Joined:
    May 14, 2012
    7,510
    3,773
    0
    Location:
    Wellington, New Zealand
    Vehicle:
    2007 Prius
    Model:
    N/A
    That and the not wanting to emit noxious gases inside (e. g. a parking building) are the only real uses for the EV button.

    Understandable rookie mistake. As counter-intuitive as it seems, you need to minimise the amount of effort to 'force' the Prius to use EV. If the car wants to run on electric, let it, just don't force it to.

    A better way to look at it is, you want adapt your driving style so that you minimise the converting energy from kinetic to potential as much as is sensibly possible. By that I mean in essence minimise both the flow of energy into and out of the HV battery.

    Now this going to seem contradictory, but you want to take full advantage of opportunities to store energy that would otherwise be wasted - slowing down well ahead if you're going to slow down anyway or inevitably stop; going down a decline. This is not free energy, but rather capturing a portion of energy already expended.

    Further counter-intuitive, your driving style should endeavor to maintain HV battery charge in the 6-8 bars range as much as possible while driving. Further to this, there are considerations if your environment could well be described as hot, which if it is you want to avoid having the HV battery resting at 7-8 bars.

    The reasoning for the shift in thinking is around the efficiencies of converting energy from one form to another, which simply put, is inefficient.

    While that sounds convoluted, the best way to achieve what I have said, is to just drive employing normal methods of economical driving and you will see the HV battery stay in the upper regions.

    I have found this to work quite well for me, 49.8 MPG (4.72 l/100km / 59.8 MPG UK) and climbing. Current tanks are averaging 51 - 56 MPG (4.6 - 4.2 l/100km / 61 - 67 MPG UK).
     
    j12piprius and oh-no like this.