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

[brick]

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.

[PaleMelanesian]

Hmmmm...

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.

Hmmmm...

Thanks for the reply. I appreciate it.

[brick]

Originally Posted by PaleMelanesian

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

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.

[PaleMelanesian]

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.

[rhwinger]

PaleMelanesian:

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.

Bob

[Dan]

Note: For previous weeks, look here, and for later weeks, look here.

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%

Key:
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

[JimboK]

Originally Posted by PaleMelanesian

I may have to break down and get a Scangauge, after all.

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.

[Bruce]

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.

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.

[mparrish]

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?

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.

[locutus]

Originally Posted by mparrish

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.

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.

*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.