What does The "B" On The Shifter Mean???

Discussion in 'Gen II Prius Technical Discussion' started by UGLYTRUK, Jan 24, 2008.

  1. UGLYTRUK

    UGLYTRUK Rented In Florida For 1 Week

    Joined:
    Jan 24, 2008
    6
    0
    NE Uppa' US
    Vehicle:
    2008 Prius
    I just rented a '08, and it has no manual. Not that I woulda' read it! I thought it might be "battery", but it doesn't seem ta change anything...

    See it here...
     
  2. KMO

    KMO New Member

    Joined:
    Apr 15, 2004
    935
    3
    Cambridge, UK
    Vehicle:
    2009 Prius
    Quick answer - "Braking". It increases the drag when your foot is off the accelerator - partly by engine braking. Use it to help maintain control and relieve wear on the brake pads when going down a steep hill.

    Someone will come along with the complex answer shortly - but that's for anoraks and efficiency obsessives, which I suspect you're not. ;)
     
  3. Ichabod

    Ichabod Artist In Residence

    Joined:
    Jul 21, 2006
    1,794
    12
    Newton, MA
    Vehicle:
    2006 Prius
    Here's the complex answer: http://techno-fandom.org/~hobbit/cars/b-mode.html

    One-handed driving w/ narration and controlling a camborder at 100+ MPH? I'm glad I wasn't on the road near you!

    Also, FYI, the Prius has a software-limited top speed, so not much need to test it ;)
     
  4. Boo

    Boo Boola Boola Member

    Joined:
    Feb 13, 2007
    5,049
    451
    Flushing, NY
    Vehicle:
    2007 Prius
    Model:
    N/A
    "B" stands for engine Braking. You might use it like a lower gear when going downhill. I wouldn't bother. Most Prius owners never use it. I've never used it in 11 months of driving my Prius. If you're going forward, just keep in Drive.
     
  5. moregas

    moregas New Member

    Joined:
    Dec 22, 2007
    58
    3
    Denver
    Vehicle:
    2008 Prius
    Better not use that B mode, the FL police is looking for you...Keep going fast. Go Prius ;)
     
  6. UGLYTRUK

    UGLYTRUK Rented In Florida For 1 Week

    Joined:
    Jan 24, 2008
    6
    0
    NE Uppa' US
    Vehicle:
    2008 Prius
    Piece a cake... Wish I coulda' gone faster... LOL!!! Ug
     
  7. miscrms

    miscrms Plug Envious Member

    Joined:
    Aug 21, 2007
    2,061
    500
    Phoenix, AZ
    Vehicle:
    2005 Prius
    "B" is for Bad mileage :p

    Its primary function is to make loud noise and waste gas. Funny they didn't label it "V8" :D

    Rob
     
  8. GreenLady

    GreenLady Member

    Joined:
    May 22, 2005
    163
    0
    Denver, CO
    Vehicle:
    2005 Prius
    Thanks for the link! The take-home message I got is to use the "B" mode when highway signs instruct truckers to use lower gear. (Gotta love all those signs on I-70 west of Denver.) :)
     
  9. Ichabod

    Ichabod Artist In Residence

    Joined:
    Jul 21, 2006
    1,794
    12
    Newton, MA
    Vehicle:
    2006 Prius
    I-70 west of Denver is EXACTLY what B-mode is designed for. I was actually going to write about that stretch as an example. ;) It's pretty fun flying down that road into Utah, but I haven't driven that one in the Prius yet. That'd be a nice 90 MPH warp-stealth glide... maybe it's time for a road-trip!
     
  10. tripp

    tripp Which it's a 'ybrid, ain't it?

    Joined:
    Oct 23, 2005
    4,718
    78
    Denver, CO
    Vehicle:
    2005 Prius
    'B' works so well there!!! Hwy 119 west of boulder is another great place to use it. It's useless in Florida!
     
  11. Rae Vynn

    Rae Vynn Watch out, I have a degree in BS!

    Joined:
    May 21, 2007
    6,024
    699
    Tumwater, WA USA
    Vehicle:
    2007 Prius
    Model:
    Two
    "B" means BEWARE!!
     
  12. Ichabod

    Ichabod Artist In Residence

    Joined:
    Jul 21, 2006
    1,794
    12
    Newton, MA
    Vehicle:
    2006 Prius
    B means "Bewitched" mode. It's great for when you find yourself low on mana.
     
  13. jrfaris

    jrfaris Member

    Joined:
    Feb 25, 2004
    352
    2
    Windward Oahu
    Vehicle:
    2007 Prius
    When I was young, we had a 57 chevy that had a GR shifter position which stood for Grade Retarder. Folks said it was for the noise it made when we used it.
     
  14. DC Prius

    DC Prius Ganzo's Driver

    Joined:
    Jan 28, 2008
    2
    0
    Washington, DC
    Vehicle:
    2007 Prius
    A comment and a question on the B shift issue:

    1: Coming down a long and winding mountain road in Shenandoah National Park, I used B the whole way down. Then, for a few days, every time I let up on the brake pedal, there was a squeak. Sounded like the car needed WD-40. After a week or so, it went away. What's the deal?

    2: When the engine turns on and off for no reason (other than to charge the battery, I suppose) does it use gas? (This may be a really stupid question...) If so, is there a way, during hohum city driving, to force it not to do this?
     
  15. Ichabod

    Ichabod Artist In Residence

    Joined:
    Jul 21, 2006
    1,794
    12
    Newton, MA
    Vehicle:
    2006 Prius
    1. I doubt if there's any causal relationship between a braking noise and the use of B mode.

    2. Don't worry too much about it. You can make yourself familiar with the warmup stages of the Prius, which require different behaviors from the system at different times. Your best bet is to get yourself into stage 4 of the warmup cycle as early in the drive as possible. Then you can minimize engine use. The engine cycling is really never for "no reason," even though sometimes you don't want it on ;)
     
  16. qbee42

    qbee42 My other car is a boat

    Joined:
    Mar 2, 2006
    18,044
    2,971
    Northern Michigan
    Vehicle:
    2006 Prius
    The squeak was probably from extended use of the friction brakes coming down the hill. Regen and B mode can only do so much; after that it's friction. You probably polished them a bit, and they squeaked until the glaze wore off.

    Tom