Tank MPG

The best I've done on a single tank:

503.8 miles at 26mph: 61.3 MPG.

Of course, if you are looking at just the best driving experience, I could do it for only half of the tank and then I went back to my miserable little commute:

252.1 miles at 41mph: 64.5 MPG

 

ok no problem. i see where you are coming from. as far as the mileage, it can be done. today, went on a picnic. drove about 35 miles on the freeway between 60-65 mph. then about 10 miles on a country road, turn off onto Skykomish River Valley Road and drove it until it deadended, then up into the mountains on a logging road about another 10 miles to Brown's Creek. this part was from 10 to 35 mph depending on how bad the potholes were

i did do a reset on B before leaving. so its another one of those partial tanks we see a lot of so i posted pics of that (trip B ) along with my tank thus far (trip A). as you can see, little difference in the numbers other than the average mph which as i discussed earlier, will always be pretty low.

im sorry if i misunderstood your post, but it sounded like you implied that people were getting high numbers because they drove intentionally slow. all i am saying is that the average speed is low over time simply because i spend a lot of time with the car on and not moving. its too bad that it does not track the average speed only when the car is moving. that would a great indicator to track

 

Dave,

Why are you doing this? It made much more sense in the Gen2, because of the difficulty getting to S4, but in the Gen3 the ease of reaching Stage 4 (in a warm car) makes it more sensible to turn the car off.

 

Ask AberdeenProving Grounds!!!!!!!!!!

 

Believe me, I understand the fun, the excitement, the thrill, the disappoinment (kind of like the old ABC Wide World of Sport's opener: The thrill of victory . . . and the agony of defeat!).

Even so, I don't understand the concern about getting a full tank in order to establish or prove something. Most of us get into routines or at least drive in regular or repeatable fashion. These routines and fashions necessarily define the kind of speeds we will drive and the mileage we'll get from our cars.

That said, I don't think 30mph is a limiter. Look at the trip odometer info I provided earlier -- 64.5 MPGs across 252.1 miles at 41mph. That isn't just a short jaunt, and I have no reason to believe that the mileage wouldn't stay there if I kept driving the same route in the same fashion. To have a 41mph average over that span means I was driving 55+ most of the time, but I had to slow and stop and turn the car off and on (and repeat the process several times). I'll grant that 20 miles doesn't prove much (but you still couldn't do it in anything other than an old Insight), but it is no different than your desire to see how high you can go at average speeds of 30+.

Different challenges; different interests; all pretty much fun!

 

You guys are killing me. I'm on my 4th tank or so, and I'm nowhere near 60mpg. My first few tanks I drove like grandma, never went into the power bar, did a lot of p&g, avoided big inclines, etc. and could squeak out 50-52 mpg over a tank. On my current tank I started driving a little more like a normal person, but still very conservative, and I'm only getting 46mpg. A little disappointing when I read these threads...of course I live in LA, and it is very hilly and the lights aren't ever sequenced, so I pretty much miss every light and am always driving up big hills...wish I could drive this car normally and get 50mpg...oh, and this is all on the display....knocking 5% off really hurts...

 

I'm with a priori on this one, why 30 MPH. What is so magic about that average speed. Why not 35 or 45 or make it interesting and say 60 MPH average. Your point is it must be 30 or better to be valid, yet your own words don't reflect that.

"My point is: people recording MPG data should take into consideration other factors like: tank vs. short trip mileage, MPH, weather conditions, cargo load, etc."

So you tell us in your initial post;

"Weather was mostly dry (rain can have a negative impact) with temperatures between 50's and low 80's (it's the Midwest, what do you expect?). Winds variable but often calm and humidity normal to high (60-90%) (Winds can definitely have an impact but not sure about air density)."

And of course your average speed of 31 MPH. So what was the temperature when you actually drove? Experience tells us that higher ambient temps can have a positive impact on MPG. What was the particular humidity level when you drove? Higher humidity means less dense air and better MPG. What was the wind speed and direction when you actually drove? Even a small amount of wind from a given direction can have a +/- 15% MPG impact. How many times did you drive in actual rain and/or on recent rain covered roads? Rain and even after the fact rain covered roads can have a negative impact on MPG. What were the loads you did cary? Even a load of 100 extra pounds can affect MPG and magnify all the other above outside influences. How about time of day of your driving? The heating of roads after exposure to the sun has an effect. Also night driving with the use of lighting can have an impact as well. So let us know, so those newbies who have the exact same conditions during the run of their tank can compare to you.

"We have to do our best to avoid false impressions of outstanding MPG readings, so newbies or those still learning hypermiling don't get frustrated with our numbers. That's all I care."

Unless you consistantly drive with all outside and inside conditions the same, a la Bob Wilsons cruise control tests of MPG vs. speed, your tank MPG is an average of a number of different drive segments of various conditions during that tank. A newbie would be better served to know how to drive a given individual segment and deal with the particular conditions encountered to improve those segments and therefore attain better overall MPG-your tank MPG your looking for-than to see a tank, be told there were numerous conditions happening and be told they have to meet certain benchmarks in their tank for it to be valid. How encouraging is it for the driver who has a 6 mile urban city commute be told their number is not valid just because they can't obtain the magic 30 MPH average you advocate.

Perhaps you need to go to the Gen II section and do some reading to see the history of discovery and improvements to MPG made by many. What you will find is that there was much talk of how to handle different aspects of the type of driving an individual was faced with. And then when any individual improved their tank average because of the work they did on the segments of their driving, the whole community congratulated them, not invalidated their results if some arbitrary benchmark was not reached. The concept of tank MPG is just to use as an overall general benchmark for the actual task of getting better MPG for each segment. Because that's how most people drive, not by the tank full at one time but in smaller increments. Yes, some people get excited at their small higher trip segment. But the important thing is at the end of the tank will they have been able to add together a bunch of those segments and had a productive tank, or are there some things they need to learn to be more consistant during those segments.

Wayne

 

Push a bit harder on that R pedal and you'll get up to 60 mph. I heard it can do 108 (at least if you are driving a Prius Gen III). Your profile doesn't say.

 

Haha, meant mpg...hahahaha...

 

My average mph is pretty low...18-20 usually. A lot of stop n' go in these parts...I do some freeway driving, but to get on the freeways here I'm usually accelerating uphill and lose a lot of gas in the process. The freeways also go through hilly areas, so sometimes you're on an incline for a mile or two...even if I'm going 60mph I have to push the accelerator down more to maintain speed. Sometimes I get long stretches where I'm going down hill, so I get some of that back, but it doesn't equal out in the long run...

My current tank is by far my worst...I'm driving just a little bit more aggressively, but my mpg has dropped from 51-52 to 46...

 

My MID for the current tank (670 km) says 3.7 l/100 km (=63.5 mpg) and an average speed of 56 km/h (= 35 mph). I'm going to empty it this week with the same or higher average speed and (I hope) same consumption (but that depends on the conditions, weather predictions say 3 beaufort :thumb. I have parked my car at home after my daily commute (90 km roundtrip) regularly with 3.7 l/100 km and an average speed of 61 km/h (= 38 mph).

And I would like to add my opinion that avg speed says very little. If I get stuck in a really bad traffic jam (you know the ones caused by an accident that you easily spend 30 min to advance 2 km) that will hurt both my consumption and average speed.

You can only compare avg speeds if they were set on exactly the same route. If you spend some distance in really heavy city traffic with loons slamming the brakes right in front of you and lights every 0.5 km, then that hurts both mpg and mph. If you live in a rural area with little traffic and no lights then it's easy to reach a 32 mph tank average while rarely cruising over 50 mph.

 

apriori,
We sometimes do more sitting than we want to at lights, traffic jams, waiting on funerals to pass etc. I will sit with the AC on while eating lunch at Sonic if OAT's are above 90 for example. I know it's counter to good fuel mileage, but I don't like sweating.
Indyking,
The point is that avg. speed as displayed on the car is not the actual average speed while moving. If you were trying to correlate anything average speed wise, then you would have to have average speed while moving. For example, I can drive 90 MPH for thirty min, and sit with the car in ready for thirty min and have an average of 45 MPH.
My trip in excess of 72 MPG was I'm sure much better than 30 MPH. Why? Because 99% of it was on rural roads with very little stopping, and a whole lot of constant 45 MPH cruising. Add in a lot of stopping and the average will decrease to around 20, and the MPG will be hurt as well because of having to accelerate a lot. Which is just opposite to your assertion of anybody can get good MPG if you have a low average speed.
I would say an average speed of 30 mph is easy to get great mileage, all you have to do is find a long, flat rural road with no stops and settle in at 30 mph for several hours. ANybody can do that

 

First I want to thank everyone who contributed to the collected data:

	Column 1	Column 2	Column 3	Column 4	Column 5
0	date	handle	mph	MPG ind (63)	MPG adj
1	5/27/09 11:08	john1701a	23	54.5	51.8
2	5/30/09 11:12	alfon	65	55.3	52.7
3	6/1/09 11:54	HTMLSpinnr	55	54.0	51.3
4	6/1/09 13:08	cultofprius	70	52.0	49.4
5	6/7/09 9:08	Jay C	73	48.7	46.3
6	6/7/09 22:50	bwilson4web	20	87.7	83.3
7	6/13/09 21:32	ken1784	29	97.1	92.3
8	6/22/09 9:25	Danny	34	55.0	52.3
9	6/29/09 9:55	zencat	22	89.9	85.4
10	7/2/09 20:20	yogadoc	31	65.8	62.5
11	7/10/09 21:21	Gwenmay	46	62.6	59.5
12	7/12/09 18:56	DetPrius	41	59.3	56.3
13	7/18/09 17:10	jay_man2	41	53.0	50.4
14	7/28/09 13:38	Philosophe	78	36.0	34.2
15	7/28/09 13:38	Philosophe	78	33.3	31.6
16	8/4/09 20:33	FireEngineer	17	91.5	86.9
17	8/4/09 20:33	FireEngineer	20	73.8	70.1
18	8/11/09 12:06	angelrob	40	60.0	57.0
19	8/15/09 14:56	alfon	62	52.0	49.4
20	8/24/09 21:43	Randysom	77	43.0	40.9
21	8/25/09 14:15	ken1784	50	75.3	71.5
22	8/25/09 23:39	ProfPrius	56	57.5	54.6
23	8/25/09 23:39	ProfPrius	68	58.5	55.6
24	8/27/09 21:57	spiderman	31	56.4	53.6
25	9/6/09 19:28	Mrgreenjeans	35	72.0	68.4
26	9/6/09 19:28	Mrgreenjeans	45	65.0	61.8
27	9/7/09 10:47	alfon	40	52.3	49.7
28	9/7/09 10:47	alfon	70	51.8	49.2
29	9/7/09 10:47	alfon	70	52.1	49.5
30	9/7/09 10:47	alfon	70	52.5	49.9
31	9/7/09 10:47	alfon	70	55.3	52.5
32	9/7/09 10:47	alfton	70	53.8	51.1
33	9/9/09 13:20	Judgeless	52	72.6	69.0
34	9/11/09 12:28	eldiee	40	59.2	56.4
35	9/11/09 15:11	DrJon	25	64.1	60.8
36	9/11/09 20:38	szgabor	16	49.0	48.8
37	9/11/09 20:38	szgabor	16	58.2	58.8
38	9/11/09 20:38	szgabor	16	57.7	54.9
39	9/11/09 20:38	szgabor	16	56.2	53.2
40	9/11/09 21:32	FireEngineer	15	97.8	92.9
41	9/11/09 23:01	pfreeus	31	54.5	52.1
42	9/11/09 23:10	banshee08	38	63.5	60.4
43	9/12/09 8:30	a priori	20	56.7	54.0
44	9/12/09 8:30	a priori	21	60.2	57.3
45	9/12/09 8:30	a priori	25	60.5	57.6
46	9/12/09 8:30	a priori	26	64.4	61.3
47	9/12/09 8:30	a priori	26	62.0	59.0
48	9/12/09 8:30	a priori	27	62.3	59.3
49	9/12/09 8:30	a priori	28	62.2	59.2
50	9/12/09 8:30	a priori	28	61.7	58.8
51	9/12/09 8:30	a priori	35	62.0	59.0
52	9/12/09 8:30	a priori	35	60.7	57.8
53	9/12/09 8:30	a priori	40	63.4	60.4
54	9/12/09 8:30	a priori	44	53.2	50.7
55	9/12/09 8:30	a priori	48	54.3	51.7
56	9/12/09 8:30	a priori	50	60.6	57.7
57	9/12/09 8:30	a priori	55	55.3	52.7
58	9/12/09 9:52	bwilson4web	24	91.2	86.6
59	9/12/09 9:54	bwilson4web	25	96.8	92.0
60	9/12/09 10:29	octavia	24	52.0	49.4
61	9/12/09 21:33	DaveinOlyWA	39	62.5	59.4
62	9/12/09 21:33	DaveinOlyWA	24	63.0	59.9
63	9/13/09 14:36	anne1965	35	63.5	60.3

This is the current graph:


This collected data tells me:

• 50-60 MPG is being achieved - even without looking at other sources, folks are achieving excellent mileage, in excess of the EPA estimates, in ordinary use. But let's look at some EPA data and user reports:

	Column 1	Column 2	Column 3	Column 4
0	model	EPA	user avg	user cnt
1	2003	41	44.9	22
2	2004	46	47.4	81
3	2010	50	51.7	43

​

• +60 MPG can be achieved - regardless of method, folks can exceed 60 MPG and even break through 85 MPG, the threshold needed to achieve a 1,000 mile tank BUT often with limitations: (1) fewer trips to minimize warm-up costs, and (2) modest speeds, to achieve 1,000 mile tank efficiencies.

Although not part of this chart, I was able to compare PnG versus the equivalent steady speed and measure a 25% increase in mileage after vehicle warm-up. So if someone is willing to spend the time and drive the profile long enough, they should be able to easily break 1,000 miles ... if that is important to them.

From this chart, I notice we're seeing a distribution of MPG across all records. Like the old GreenHybrid database, this suggests that it is the 'luck of the draw', where one lives and based upon their ordinary driving requirements, more than anything else, that defines vehicle mileage. Some have access to routes and profiles that are mileage efficient. Others don't but are still getting good mileage. There is an old saying:

Perfect is the enemy of good enough.
​

Can the car be made or operated more efficiently? Probably.

I would first look at warm-up techniques since longer drives are more efficient and seeing what can be done to improve shorter drives:

• optimized warm-up protocol - needs investigation
• block heater(s) - more than 400 W and 30-35C rise
• plug-in lite - tickle charging the traction battery at night
• bumper air inlet closing to retain heat and reduce drag

To me, this chart is 'managing user expectations.' It lets us see in one place what the community is achieving ... and it is good! Compared to ordinary cars, it is over twice the USA fleet average, ~25 MPG.

Can we do better, probably. But we've only had this car in our hands for 120 days and the hardcopy maintenance manuals have just started shipping. Do the old trick works, some do. Regardless, I know the next year will be fascinating for the prius gear-heads.

Bob Wilson

 

oh i dont really know. habit i guess, its like not turning off the computer because in 3 minutes the monitor will go to sleep. hard drive will sleep in 10.

besides i never intend to let it run more than 5 minutes or so. its run in and run out, but sometimes i get sidetracked. the other day, their internet (my mother in law) quit working... so i did what EVERYONE knows... power cycle the cable box and the router...connected.

then had to show her how to attach a file to email, brief instructions on creating folders (she had literally 150 files on her desktop!!) to put stuff and that eventually, she will start losing stuff even if its in plain sight...