Week of Feb. 5th - Feb. 11th, 2007

Discussion in 'The Daily Grind' started by brick, Feb 5, 2007.

  1. brick

    brick Answers to "that guy."

    Have you read about the ScanGauge? That's what most of us use when we're in a car that doesn't have its own built-in feedback. Worth its weight in gold if you are interested in fuel economy.
  2. PaleMelanesian

    PaleMelanesian Beat the System Staff Member


    I like it, but in my situation, it'd be a year before it would pay for itself. If prices go up... could be as little as 6 months.

    My goal here is to make a much a difference as I can while still doing the same things I already do. I'm already driving every day, so I can just drive better. I already put air in my tires, I just change the amount. Buying a gadget is a psychological step I'm not sure I'm ready to take.

    Lazy / cheap is the approach I'm taking at this point.


    Thanks for the reply. I appreciate it.
    Last edited: Feb 7, 2007
  3. brick

    brick Answers to "that guy."

    You could always try Ebay for a second-hand original ScanGauge. It isn't quite as pretty as the ScanGauge II but it does everything just as well and could probably be had for half the price. And if it's about just letting the efficiency come to you (a perfectly fine approach as long as you are willing to put **some** effort into it) having that instant feedback might just do the trick for you. What tends to happen is that the user gets used to seeing the feedback while going though the day-to-day and, over time, adjustments are made naturally.
  4. PaleMelanesian

    PaleMelanesian Beat the System Staff Member

    I'm willing to change my driving style dramatically. I'm already trying the various techniques to drive efficiently. I just can't tell what is making a difference, when I'm not getting feedback until 3 days later. I may have to break down and get a Scangauge, after all.
  5. rhwinger

    rhwinger Well-Known Member


    I don't know if this will help, but it might be worth a try. After a few thousand miles of driving, I have developed a "feel" in the seat of the pants for when the car is performing efficiently. The engine just smooths out and just kind of, I don't know, purrs or something. When the engine vibration drops, I can see the mpg indicator climbing, or peg high when this situation develops.

    Maybe you can try driving, looking for that "sweet spot"?

    Oh yeah, almost forgot - try installing a manifold vacuum gage. Probably $25 at the local gear head shop. I think high vacuum equates to high mileage - but don't quote me on it??

    Just an idea.

    Hope it works for you.

    Last edited: Feb 7, 2007
  6. Dan

    Dan KiloTanked in post 153451

    Note: For previous weeks, look here, and for later weeks, look [post=20664]here[/post].

    OK... here's my last six days and 19 trips. Discovered NICE-on a few days ago and it's helped a lot on my drive in. Also working with DWL. Most of my losses are due to warmup time and short trips, or missed lights.

    The error (last column) is associated with rounding errors in my calculations.

    #  Notes                                 Start         End           mpg_  Trip  T   50W Er±
    == =========                             trip  mpg_SoC trip  mpg_SoC avg   mi    °F  car_mpg
    01:Drive in Tue Feb 6 tried CC @47mph    458.2 53.4 6  472.0 53.5 6  57.05 13.8 48.0 ?   3.8
    02:Drove to Sam's to fill up.            472.0 53.5 6  474.5 53.5 6  53.50 2.5  66.0 ?   21.
    03:Drove from Sam's after fill up.       0.0   46.2 6  2.6   46.2 6  46.20 2.6  66.0 ?   0.1
    04:Krogers on way home                   2.6   46.2 6  5.7   50.9 5  55.65 3.1  66.0 ?   0.1
    05:Krogers to house                      5.7   50.9 5  17.4  61.7 4  68.81 11.7 62.5 ?   0.0
    06:Drive in Wed Feb 7, tried CC @41mph   17.4  61.7 4  31.2  59.6 6  57.15 13.8 57.0 ?   0.2
    07:Went out to lunch                     31.2  59.6 6  33.4  58.6 6  47.34 2.2  68.0 ?   1.4
    08:Came back from lunch                  33.4  58.6 6  35.4  57.5 6  43.78 2.0  71.0 ?   1.5
    09:Went to Dinner                        35.4  57.5 6  40.0  56.6 4  50.52 4.6  75.0 ?   0.8
    10:Went home from Dinner                 40.0  56.6 4  57.1  57.6 6  60.08 17.1 71.0 ?   0.3
    11:Drove in Thur Feb 8; nice-on,_dwl, sw 57.1  57.6 6  70.9  58.6 6  63.14 13.8 66.0 3.5 0.5
    12:Drove home (hit 2 lights hard!)       70.9  58.6 6  85.0  58.7 5  59.21 14.1 69.5 3.0 0.6
    13:Drive in Fri Feb 9; new route; EV_    85.0  58.7 5  99.4  58.9 6  60.11 14.4 51.0 3.5 0.7
    14:Drive home messed up nice-on          99.4  58.9 6  112.4 58.8 4  58.05 13.0	49.0 2.0 0.8
    15:Trip to get videos and food           112.4 58.8 4  135.2 59.4 4  62.55 22.8 47.0 6.0 0.6
    16:Trip to clients                       135.2 59.4 4  162.8 60.5 5  66.54 27.6 45.5 3.5 0.6
    17:Trip home from clients                162.8 60.5 5  190.2 61.5 6  68.20 27.4 49.0 8.0 0.8
    18:Went to Church Feb 11; cold start+hwy 190.2 61.5 6  202.0 60.8 6  51.37 11.8 48.0 2.0 1.2
    19:Came back from Church; warm start+hwy 202.0 60.8 6  213.5 60.7 6  59.00 11.5 51.0 0.0 1.7
    Current city 62.01%                      Goal EPA_mpg for current city/hwy split = 57.93_mpg
    Current hwy  37.99%                      Current_mpg for current city/hwy split  = 60.38_mpg
    Difference = 104.23%
    Start_Trip = The trip/tank mileage when I started the drive.
    Start_mpg = The tanks mpg via the FCD at the start of the drive.
    Start_SoC = The number of bars on the battery icon at the start of the drive.
    End_Trip = The trip/tank mileage when I finished the drive.
    End_mpg = The tanks mpg via the FCD at the end of the drive.
    End_SoC = The number of bars on the battery icon at the end of the drive.
    mpg_avg = The calculated mpg for this drive.
    Trip_mi = The length of this drive.
    T_°F = The average temperature for this drive
    50W_car = The number of green regen cars that show on my consumption screen
    Er±mpg = The range of error associated with mpg_avg
    Last edited: May 16, 2007
  7. JimboK

    JimboK One owner, low mileage

    I too didn't want to spend the money, but I found a used SGI for, as brick suggests, half what a new SGII costs. (Bought it from another member on PriusChat, not e-bay, but that's beside the point.) I agree with him that it's well worth it.
  8. Bruce

    Bruce cheapskate

    If you have a birthday coming up, ask for the SG as a gift. My experience is that it's unlikely to save enough gas to pay for itself unless you drive a lot, but sure is a lot more likely to than other fun electronic toys, and it's just as entertaining. Heck, you can even change the display color to match your mood. :)

    Awesome long commute this morning...41.8 in the low teens. I pulled off a couple of D-FAS for the first time this morning. :D

    Question: when doing a D-FAS, is it best to let the target go to maximize the glide or just stay in the draft? I suppose the answer depends on the frequency of potential targets (density of truck traffic).

    38 MPG back to my normal workplace, filling up a 35 MPG tank along the way.

    Expressway was jammed up through the on-ramp going home, so I took back roads and managed to squeeze out 33.6 MPG. I was doing around 31 MPG on a slightly more efficient route last summer.
  9. mparrish

    mparrish Rosie the Riveter Redux

    Tank sitting at 60.9, with 3 pips left. Temps in the 60s in Central Texas have certainly helped. I'm still likely to score my first 60mpg tank, as I still have half a week of commuting left. Where is that woot icon? :) :woot:

    Consistently averaging 75+ mpg on my 12 mile -400 feet commute to work and 55 mpg 12 miles coming back home uphill. My goals are still 85 in and 60 out by the spring. As awesome as 85 sounds, getting to 60 going back uphill seems more of an accomplishment to me.

    One thing I've learned is...........hills are a killer that are hard to recoup. I have two alternate routes back home that have more glide opportunities, but they also involve at least one big climb. A third route with fewer glides and no big hills does better.

    I've been wondering whether it would be easy to create something like a "temperature adjusted MPG" chart that is reasonably accurate. Given the brains on this site, I bet it either already exists somewhere or is just not worth the trouble. I find myself reading about 42 mpg tanks in 2 degree weather and wondering.........."wow, is that great, REALLY great, or PHENOMENAL?" All I know is, that's COOOOOOOOOLD. :)
  10. locutus

    locutus MPG Centurion

    You mean something like this?

    This is my data since september '05, about 950 segments worth. Obviously there are many other factors, but what this says (at least for me) is, all other things being equal, every degree F increase in temps is worth about 0.3 MPG. For me that has meant about 45 at 0F, about 54 at 30F (heh, why does that seem low all of a sudden? ;) ), 63 at 60F, etc. It's probably not perfectly linear but it does give some idea. What I might do is the same for data involving just one particular trip (eliminating a bunch of other factors that vary widely between trips, and probably getting a better fit).

    Congrats on your 60MPG tank by the way. :cool:

    *Edit*: Here's one for a particular trip (my morning commute) - the temperature/MPG relationship is definitely stronger once a bunch of other variables (distance, time since last start, etc) are eliminated.

    Last edited: Feb 8, 2007
  11. Dan

    Dan KiloTanked in post 153451

    Ok... Started [post=20401]posting[/post] on my commutes. Tanks average is down to 57.6. It's perfect temp here, so I don't have many excuses. Hopefully breakin will start to boost my mileage in the next few months.

    I definitely need to cut out my short trips. Even in Texas there is some warm up. I've been playing with NICE-on, but don't know if its a bad idea on a Prius.

    Also having problem with tailgaters, can't seem to stay in my glide without seriously hurting my driving karma. Think I need to get a "Student Driver" sticker to encourage them to pass.

    Anyway, I'll probably test out some different routes to see if I can't find a deserted road without stop signs that is devoid of all traffic during rush hour. Wish me luck!
  12. Bruce

    Bruce cheapskate

    36.2 MPG at 15°F for 15.4 miles this morning, a bit of wind.

    A semi was tailgating me with brights on and the second light had a surprisingly short cycle, so I muffed both -- light up to make the green, then brake for red. The second light was so short I didn't even get a chance to put it in drive.

    I accelerated into my gap to the next car to maximize the last glide before the expressway, came in too hot and had to touch the brakes during the glide.

    No draft targets on the expressway until a semi pulled in front of me at the last hill before my exit, so I started the coast down to the exit with a D-FAS.

    Not too bad, all things considered.
  13. brick

    brick Answers to "that guy."

    Filled yesterday. The tank came in at 47.5mpg on the MFD for the second time in a row (albeit 54mpg calculated...riiiiiiiiight). So now I'm parked at about 40mi on the new one with 48.0mpg showing. First pip left me at 30 miles. This 10F morning, 25F afternoon crapola has got to end.
  14. Skwyre7

    Skwyre7 Well-Known Member

    55.8MPG at 23ºF on my morning commute. I'm pleased.
  15. Chuck

    Chuck just the messenger

    An accident diverted me to the tollway this morning, which took a hit on my commute. At 45F, it was 70.7mpg, but probably should have been around 75 on the non-toll commute. The tollway has more hills - that's probably what is doing it.
  16. locutus

    locutus MPG Centurion

    I'd be happy with that right now. ;) 45.4 into work this morning at -6F. We're in the -5F morning, 15F afternoon pattern here. Sunday's high is finally above 20F. 2 days until my block heater is installed, that's all I can say. At least roads are clear and winds are fairly calm.
  17. dcoyne78

    dcoyne78 Well-Known Member

    The average temp here was 1 F yesterday and the average for the week has been 5 F, I am at 57.4 MPG for 296 miles on the display (this has run about 2% high long term so my real FE is probably about 56 MPG), which I am pleased about considering the temps. The first 107 miles were a net downhill of about 1170 feet where I managed 61.5 mpg, since then my avg FE has been about 55 mpg (using the method outlined above.)

    If someone is too cheap to buy a scangauge(maybe you aren't, but I am), you can use a paper, pencil, and calculator or spreadsheet to find out approximately what your FE is for any segment.
    For example:
    you have 100 miles on your tank and the avg mpg is 50 MPG, so you have used 2 gal of gas so far (100 mi/ 50 mi/gal)= 2 gal. Now you make a 50 mile trip and bring the avg mpg up to 52 mpg now you have used (150/52=2.885 gal). What is your FE for the 50 mi segment? It is 50 mi/.885 gal=56.5 mpg. Thanks Wayne for showing me this trick way back when you first tried Carl's Prius. This is a lot of calculating but a spreadsheet can be set up to do the calculations for you. You simply need miles at start and end of segment and the avg MPG at the start and end and you can get an approximate FE for your segment. The scan gauge is nicer because you can see how you are doing in real time, but this gives you some feedback after each trip if you are willing to punch the numbers into a spreadsheet. This is only necessary for Prius owners, although HCH owners that use one of their trip gauges for lifetime mpg could use this as well (are there only two trip odometers, I am not really sure about the HCH?)
    I created a little spreadsheet tool for calculating MPG for a segment. It can be found here.

    Last edited: Feb 8, 2007
  18. dcoyne78

    dcoyne78 Well-Known Member

    Have you tried blocking your grill using foam pipe insulation cut in half and stuffed in the grill vents? See prius chat for details and pictures, I am doing this along with the block heater and it has made a huge difference this winter.

  19. dcoyne78

    dcoyne78 Well-Known Member

    You might try an EV button install, I just use the headlight flasher as my switch, the install is pretty easy, I think I found the instructions over at Prius Chat. Also when the engine is cool you can often get the ICE to shut down once you get your speed over 35 mph, but the EV is an easier fix for speeds under 33 mph, just don't over use it when you first start the car, let the engine warm up by driving about 2 min or so before you start using the EV button, unless you are just moving your car a short distance at parking lot speeds.
    You might not want to do this due to warranty issues, I did it on my 2004 at around 44000 miles, on a new 2007 I'd probably chicken out.

  20. locutus

    locutus MPG Centurion

    Yep, did that a month back or so. Cheapest mod to date. :) I have no doubt it has helped everything to stay warmer when it's frigid like this, but there are other big things that are hitting the MPG more than that helps:

    - a commute of only 6 miles (fully warmed up only at the very end)
    - starting from temps of 20-30 in a garage left overnight or for 8 hours during the day <-- block heater will help with half of this one
    - once it gets below about 10, my EV button doesn't work despite what coolant temp says :(

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