My best tank yet!

Calculated will likely be under 60 mpg. Still very good, but please calculate.

 

Wow.

 

Do you know what if you pumped E10 or 100% gasoline? Mark57 did a tank at just over 800 miles with 100% gasoline. By my calculation, you better go put gas soon or else you're going to run out of gas.

 

I have 24,000 on my 2010 and have yet to get under 62 mpg on the last 8 tanks of gas with mixed driving with an average mph of about 40. The 62 mpg is the MFD, actual pump is 2.45 mpg less. But great for any car that is this big and heavy. Highest tank so far is 64 mpg. The warm summer temps sure push the mpg up

 

Very nice numbers!

My Commute keeps me at an average speed of 53mph so it's hard for me to get higher than 55mpg. I'm jealous of your numbers. : p

 

I wish the Genii had a standard tank. I can never get more than 10 gallons in my tank and that is after driving with a flashing pip for 30 miles.

 

Very nice numbers indeed.

Did you I apply the P&G techniques? Or just drive moderately?

How many miles do you averagely travel per day?

I find your tire pressure much higher than the recommended 31-33psi. Is it necessary to go 40+ psi?

 

I have found over the life( 24Kmi) of the car ( 2010) that the difference for me is about 2.4 mpg ,.Display reading that amount higher than actual calculated by dividing miles traveled by gallons pumped to refill it.

 

Very nice numbers.

The whole point of posting "calculated" mpg is it's the "real" mpg. The indicated number looks great but it's just a guess. That's not being anal, that's being accurate. If you post your real calculated mpg the members will take you much more seriously. Just a friendly suggestion.

PS, my high mpg tank was 80.8 mpg indicated and 76.418 actual mpg over 522 miles. The high mileage tank was 805.2 miles @ 79.3 mpg indicated and 75.016 actual mpg.

 

The error I'm seeing, year to date with ours, is 6.6%. What bugs me:

Toyota appears to have made a conscious decision to BS the mileage numbers. I don't like that, and it bothers me that Prius owners put on their rose-tinted glasses, buy into it, even with an "indicated" disclaimer. It perpetuates Toyota's license to BS. I'd like to see Toyota fix this. 6~7 percent is significant.

The Toyota Prius is not the only car on the road. There are other manufacturers with in-dash mileage display that don't follow this disceptive practice. With the Honda Civic Hybrid for example, in-dash display of mileage is invariably pessimistic. It still lags the Prius, at least around town, but it doesn't sugar coat it.

A simple fix, if you don't want to be tied up with calculations: knock 7% of in-dash displayed mileage when posting, and you'll be honest.

BTW, we're by no means hypermilers, just trying. My wife is the principal driver, and a lot of it is short trips. Our best calculated mileage for a tank this year was a meagre 53.1 mpg (4.4 liters/100km). Overall calculated mileage since the first of Jan: 46.9mpg (5.0 liters/100km).

We've got the 17" tires, has some impact. OTOH, we use a blockheater pretty religously, for the first start up of the day.

 

It's simple. Don't choose a %. Just list your MFD calculated mpg and your hand calculated mpg.

 

As you know, a lot of engineers/scientists/others are very technically oriented and like their data as accurate as possible (within control of the user). They will accept that there will be pump to pump variations at gas stations, but if you were to report a rate (miles per gallon), they will want to know if it is the indicated (computer) or actual (hand calculated miles/gallons replaced). I definitely fall into the latter category.

I tracked my mileage over the course of a year, both HSI indicated and calculated. I found that indicated, I averaged 61.7 mpg, calculated was 58.2 mpg. Thus a 3.5 mpg difference. This is important because it gives me a more accurate assessment on my tank range.

I don't know if the % will change with average speed/commute length. I don't know if the mpg difference will change with average speed/commute length. What I do know, is that looking at my indicated MPG and subtracting 3.5 mpg, gets me very close to my calculated MPG come fill up time.

Collect your data and see where your car falls in. What is indicated for Ted Johnson may not be your results (Your mileage may vary).

BTW, great tank! I don't want to push mine that far.

 

Excellent.

I have read similar testimony from Posters/members
on Cleanmpg.com who have also reported being able
to fill the 2010 Prius slightly over 12 gallons -
one reported that before putting in the last one or two
gallons - he shook the Prius slightly to get rid of the
airbubble that could be trapped in the fuel tank.

I've been told via the Prius Yahoo! group that when the tire pressure set at 50psi/48psi that a hypermiler can get as high as 77 mpg per tank in the summer and 55 mpg per tank in the winter. While I haven't been able to achieve this level of fuel efficiency - I am getting closer. This summer I've been experimenting with the 50psi front and 48psi rear tire pressure setting on the Yokohama Avid S33. Using a ScangaugeII to monitor my fuel usage, my 2010 Prius was able to achieve 70 mpg(calculated at the pump) over 658 miles using E10 gasoline on my last fillup (8/1/11). Last summer(2010), my best tank was 66 mpg over 340 miles (9/7/11). Not quite as good as 76 mpg over 800 miles but I don't have access to 100% gas like Mark57 does . However, Mark57's latest MPG record suggests that the 77 mpg per tank(calculated at the pump) in the summer is a reachable goal.

BTW: Both my ScangaugeII and my Prius Main Fuel Display(MFD) provide an estimated MPG but in my logbook I normally record the only calculated miles per gallons a particular tank fillup, e.g. the miles travelled since the last fillup/ the number of gallons of gasoline used to fillup the tank. This number is normally slightly lower than the MFD and the ScangaugeII (albeit when properly calibrated each fillup the ScangaugeII can be more accurate the onboard MFD).

 

Congratulations! I just hit 62.2 mpg today for the first time so I can imagine your excitement!

 

I have a G2 Prius. I tracked MFD and calculated MPG for about a year and found the MFD under-reported the calculated MPG by ~ 3%. As mentioned above, My SG reports trip MPG about 3% higher than the MFD, so I report the SG results these days.

I'd prefer that people do not report differnces in absolute MPG differences though, since the discrepancy averages out to a fixed percentage that will give different absolute numbers. E.g 3% of 60 mpg is 1.8 mpg, but 3% of 45 mpg is 1.35 mpg.

Like F8L says, most of this argument over accuracy can be resolved if drivers simply report calculated MPG; or as a nice second choice measure the reported/calculated discrepancy percentage for their car over 5 tanks or so and use that fudge factor in the future.

If you are anal enough to hypermile, then you are anal enough to report your results accurately

 

^^ Are you talking to me treehug ?
Does illogical mean unexpected?

Feel free to look at and play with the data yourself: Data

The pump calculations are a bit more accurate than the MFD results because the MFD reports only one decimal place of accuracy, while the pump reports 3 decimals accuracy of gallons pumped.