Which is better?

Discussion in 'Start Your Journey Here' started by BobLoblaw, Oct 13, 2008.

  1. BobLoblaw

    BobLoblaw New Member

    Hey, all - saw a couple of tv stories this summer and had my class (I teach) do a presentation on hypermiling. I've been trying it with my limited knowledge since that time and being competitive, try to beat my mpg each tank of gas. I've definitely improved and things that I'm sure I used to do are now no-brainers and I find myself silently judging people that are speeding up toward the time they get to slow down at the stop light! :) Kidding.

    Anyway, my question is when I'm driving to work, I could go 60 mph, which I've read is the recommended consistently the entire way. Or, I could go 70 or so and then coast (I think this is the P & G method, but haven't found a terminology thread yet for all these acronyms). Anyway, is it better to drive at a consistent pace or to P&G...I know there are probably a lot of variables depending on the drive and whether it's flat, hilly, etc., but thought I'd just throw that out there.

    Also, is it better to coast slowly (I've found I can make the last .8 miles home in neutral, though by the end I'm going pretty slowly and it drives my wife crazy - haha), or to just accelerate a bit, coast and get there more quickly thereby turning the car off more quickly? I guess I'm just uncertain of how much gas is being used when you're not accelerating...sorry these are such rookie questions, I'm sure!!

    I'm sure I have a few other questions, but I'll start with these. Thanks, in advance!
     
  2. BudgetFitting

    BudgetFitting FAS Convert

    Welcome to the board!

    By the way, how is Bob Loblaw's law blog?

    A constant 60 mph vs. a high speed pulse and glide- Due to wind resistance, you will probably be better off with a constant 60 mph. Especially since I take it you are keeping the engine on and coasting in neutral.

    Now, if you were to P&G at lower speeds, say 55 mph and coast down to 40 mph; you would get better gas milage than if you had just driven a constant 55 mph (an even bigger gain will be seen if the engine is shut off during the coast).

    In terms of your coast home, again I will assume you have the engine on and are coasting in neutral (since it was not explicitly stated in your post). I have read that the mph you are going while you coast in neutral with the engine on can be multiplied by 4 to get an estimate of the mpg you are currently seeing. I would imagine that if you are going 10 mph or higher it is best to remain coasting. Though a scangauge would be the best source of info as to what is most beneficial.
     
  3. ksstathead

    ksstathead Moderator

    Welcome. Try DWL instead of steady speed. Bleed a little speed up hill, let gravity bring it back. DWL is more or less steady throttle, versus steady speed. think of this as a loose cruise control. It's easier to do in traffic than P&G.

    Folks knocking out big numbers drive slower and P&G. Folks knocking out astounding numbers are driving slower and P&Ging in a FASable car (manual trans. or a flat-towable automatic), with engine off on the glides.

    Sorry for the acronyms.
    good luck.
     
  4. phlack

    phlack Well-Known Member

    I'll agree with these numbers.

    -Mike
     
    Last edited: Oct 15, 2008
  5. PaleMelanesian

    PaleMelanesian Beat the System Staff Member

    It's simply a math function of your idle gph and your mph. mph / gph = mpg.
     
  6. BobLoblaw

    BobLoblaw New Member

    Thanks so much for your replies! And, budget - love it that you picked up on the Arrested Development (RIP) humor! :) I think I'm going to try to get one of the scan gauges from the offer on here - I saw on another thread someone ask if they'll work in certain vehicles and the answer was such that it seemed obvious that these will work with any vehicle. Is this correct? I ask b/c I have a '97 Accord and don't want to spend the money only to find out there's nowhere to plug it in (or whatever you do)...sorry, very car illiterate! :( But, hey, I'm trying!! Thanks again!
     
  7. phlack

    phlack Well-Known Member

    For those who saw my post before, I'm retracting it.
    4x your MPH is actually pretty accurate. At least in my vehicle. I paid close attention last night, and when gliding at 45mph, I indeed got about 180mpg, give or take.
    If I was gliding at 35mpg, I indeed was getting an instantaneous 140mpg or so.

    It seemed pretty high to me, but that's what the scangauge tells me.

    This is at an idle of ~.22gph. If your vehicle idles higher, then your mpg will definitely be lower.

    -Mike
     
  8. jhu

    jhu Well-Known Member

    I find P&G gives better mileage with my car than the other methods.
     
  9. 93Hatch

    93Hatch Well-Known Member

    Click on the glossary in the green navigation bar on the left side of the page. Most commonly used acronyms are also already linked.
     
  10. 98CRV

    98CRV Well-Known Member

     
  11. BobLoblaw

    BobLoblaw New Member

    Thanks for additional comments and the guidance to the glossary! :)
     

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