92.04 mpg from a Prius II on my first attempt?
 

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Re: 92.2156 mpg from a Prius II on my first attempt?
 

Wayne,
I have a spreadsheet set up to make that calculation and yes, I can confirm that you got 92.1 MPG. Just think what is possible when your friends Prius when it is fully broken in?

Hopefully you can show me a thing or two!
Dan

Re: 92.2156 mpg from a Prius II on my first attempt?
 

I looked at the arithmetic and it seems right, but my quick off-the-top-of-my-head estimate is about 82 mpg (3 parts at 60, 1 part at 'x'). I'll figure out which is right after I wake up a bit more, and finish watching Le Tour.

Addendum: I agree with your arithmetic.

Superb result. I presume you took a round trip. Any wind advantages ? What speeds did you drive ?
Perhaps I'll go back to some of your old posts where you insinuate that the 2G is overated, lol.

Re: 92.2156 mpg from a Prius II on my first attempt?
 

Wayne,
congrats on those stats!
Could you give us some more info on the type of driving you did:
Mean speed, how constant, type of road (including elevation changes), temperature and humidity, traffic, etc...
Also, do you have any idea what the tire pressures were in your friends Prius?
Very cool!

Re: 92.2156 mpg from a Prius II on my first attempt?
 

Wayne, that's just ridiculous. You should be studied under a microscope because you do the impossible.

Was your ride round-trip or on increasingly lower altitude roads?

Re: 92.2156 mpg from a Prius II on my first attempt?
 

I think the math may be a little off:

Where do you get your gallon figures?

I think you need to add them, not subtract.

If you get 59.7 mpg then 65.5 mpg, the average has to be between
these two numbers in normal math.

Patrick

Re: 92.2156 mpg from a Prius II on my first attempt?
 

miles/mpg = gallons (check the units)

Gallons used up in the tank, minus the gallons used before Wayne started his trip, equals the gallons used during the trip.

Then, trip miles/trip gallons = trip mpg

Re: 92.2156 mpg from a Prius II on my first attempt?
 

To many assumptions are being made here. You cannot extrapolate gallons from the MultiFunction Display (MFD) with any accuracy. The MFD is a rough indicator of current Miles per Gallon. In my Prius II, the MFD is off by plus or minus 15%, which is huge. Most of the time it is within 5-7%. Once it displayed 25% higher than actual (for an entire tank).:omg:

The only accurate way to measure mileage is to fill (and top off) the tank at the same gas station and pump at every fill up, then do the math Miles driven/gallon used.:)

Last time I filled up, and drove home from the station, and I recorded 99.9 MPG on the display (a little over 2 miles):), but the next morning when I left for work, it immediately dropped to 54 MPG (in a block or two).:angry:

Have your friend log his tank data in the Compare section on this site.:lightbulb

Re: 92.2156 mpg from a Prius II on my first attempt?
 

LOL!!!!

Re: 92.2156 mpg from a Prius II on my first attempt?
 

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Re: 92.2156 mpg from a Prius II on my first attempt?
 

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Re: 92.2156 mpg from a Prius II on my first attempt?
 

Edited: Recalculating with data from krausdb's post.
Assuming that the MFD mpg data is systematically 1.5% high and assuming that the random error is +/- 0.5% then I get that the Wayne's mpg is between 85 and 94 mpg. Don't put too much faith in these calculations until we know more about measurement error of the MFD. But, I'm now more confident that Wayne's mileage was really in the high 80s to low 90s, which is really excellent. I'm more tempted to buy a Prius after these results (and looking at krausdb's excellent results in hypermiling with a prius II.
--Walter
PS This remains a calculation that is more sensitive to random errors in the MFD than you might guess. I've left the old calcs below for anyone who thinks their MFD error is larger.

Hi Wayne, Your calculations are correct, but I wouldn't put too much faith in the answer because of uncertainties in your data. According to Douglas, there can be errors in the mpg in the MFD of +/- 15% with 5-7% common. Redoing the calculations with +5%error in the first MFD reading and -5% error in the 2nd MFD reading I get:
mpg for 375 miles: 62.685 gallons for 375 miles: 5.982
mpg for 501.1 miles:62.225 gallons for 501.1 miles 8.053
gallons for 126.1 miles 2.07
mpg for 126.1 miles: 60.896

Lesson: This kind of calculation can be sensitive to errors in the MFD mpg.
How likely are my numbers here? Not very!! There is a low probability that the errofs in the two MFD readings just happen to be in the direction to make your mpg as bad as possible. To be fair I calculated your mpg with the opposite errors (to make your true mpg as large as possible with +/- 5% error in MFD).
Then you get 187 mpg!!!

So what mpg do I think you got? The most likely is your calculation of 92.1127 mpg, but with a fairly large standard deviation. If I get ambitious, I could calculate the standard deviation (with lots of wild guesses on the statistics).

Additional knowledge that really should be included in the statistical calculations is that Wayne is really good at this, so I imagine the reality is well over 65mpg. [Now looking at the breakdown in segments, I would guess that +/- 5% random error is high because of the consistency in the segment readings and would guess that the truth is closer to 90 mpg than to 65].

When your friend finally fills his tank it would be interesting if you report how the MFD and actual mpg compare.
--Walter

Re: 92.2156 mpg from a Prius II on my first attempt?
 

Great job. The only reason the numbers could possibly be wrong is because you don't know exactly how much gas you used. Are you sure the tank was filled to the exact point as the previous tank? If you were off by .4 gal it would drop your mileage drasticly. You need a few tanks to realy be able to determine your mileage. The more tanks you put in the more the margin or error goes down.

I'd guess by your track record you got around 70mpg. How long will you be able to borrow the car for or was it just for that one trip?

Re: 92.2156 mpg from a Prius II on my first attempt?
 

After reading through these posts I just wanted to make a few comments. It has been suggested that the only way to know for sure is if the MFD rreading is correct is to ensure that the tank was filled to the same level before and after. While this is certainly true, it is very hard to do given the variables of temperature and bladder temperment while filling.

I have made calculations such as Wayne's a hundred times (that is why I developed a spreadsheet for it) and I have found after filling the tank that the calculation is quite accurate. In fact, over 47000 miles of Prius fills I can say that the MFD has never been off by more than 5% from the gallons pumped. Over that period, the average has been a 1.5% MFD overstatement. I would say that with the data I have collected, IMHO, it is more accurate to apply a 1.5% penalty to the MFD than to base a conclusion on how many gallons it took to fill the tank. That is because I have 90+ tanks of data that serve to smooth out all of the individual errors associated with filling one tank.

Re: 92.2156 mpg from a Prius II on my first attempt?
 

i'm sorry, did you say that you filled the tires up to 52 psi?!?!?

Re: 92.2156 mpg from a Prius II on my first attempt?
 

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Re: 92.2156 mpg from a Prius II on my first attempt?
 

Cruising at those speeds on relatively flat ground I've noticed instant, and average FE of 2.5 l/100km ~94MPG so I'd say it's perfectly possible to get 92 MPG, given some stopping and starting. The problem around here is the hills: pretty much anywhere we go is up and down several big hills, so FE is just trashed, especially with traffic usually going 10-20 km/h over the limits and plenty of stop lights. It must be so nice living on flat land... I now envy the drivers over in Saskatchewan. :P

Re: 92.2156 mpg from a Prius II on my first attempt?
 

Hmm... I see you have discovered the Prius II magic Wayne :-) Remember the 1000 mile tank we talked about last year? Perfectly doable if you run the car non-stop. But no sleep for 24 hrs of course :-)

Now about gliding, in places that are not all that flat, it would really help if you find a route that has strong climb and gentle slope down. You can then do all the climbing in one go and then glide for a very long time. The opposite would be quite bad because you need to pulse a lot to go up the gentle slope. Every pulse has a startup cost, you really don't want to do it very often. And also the big downhill will require you to brake too hard to regenerate much of the energy.

That's way route choice is very important here. I have evaluated alternative routes extensively for most of the places that I need to visit on a regular basis. My wife always get really upset when I take all these strange detour :-)

Andy

Re: 92.2156 mpg from a Prius II on my first attempt?
 

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Re: 92.2156 mpg from a Prius II on my first attempt?
 

Wayne,
Im not a statistician but I would buy the 92MPG number +/- 2%. And congrats to Carl, the next Prius Hypermiler in training! I'd like to meet him also next time I'm in the area.

Re: 92.2156 mpg from a Prius II on my first attempt?
 

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Re: 92.2156 mpg from a Prius II on my first attempt?
 

Me finding P&G useful? You might not remeber it but I mentioned it to you last year before the winter. I take the train instead of drving to work these days because my client site is downtown. So I'm mostly driving short trip during weekends. Mostly sub-10 mile each way, sometimes as low as 2-3 miles, in full city traffic. How else does one get 60mpg without some kind of pulse driving? :-)

As for the 1000+ mile tank, I've always said that the car can do it no problem. The real question is whether the driver can go that long non-stop. Multiple people sharing the driving would be much more practical I think (Dan might disagree though :-) Want to get a couple of guys togther and just do it?

FWIW, my difference after 10,000km is 1.27%.

Andy

Re: 92.2156 mpg from a Prius II on my first attempt?
 

Where can I get more info on the P&G technique? I have an '06 Escape that I'd like to try it on. That should help validate the technique. As you can see below, my current milage could use a bit of a boost.

Scott

Re: 92.2156 mpg from a Prius II on my first attempt?
 

check out the last post of page one and the first post on page two of this thread.

I don't know if we have had any confirmation that Pulse and Glide works with the Ford Escape Hybrid. But report back in the Escape Forums and let us know how it went. My gut tells me it is a little more difficult in the FEH.

Re: 92.2156 mpg from a Prius II on my first attempt?
 

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Re: 92.2156 mpg from a Prius II on my first attempt?
 

Work's been pretty crazy for the past little while so I haven't been following the marathon very closely. I understand Dan is talking about making it an annual thing now. So next year perhaps... My wife winced when I told her about the marathon. But we'll deal with that when the time comes :D.

In any case, congrat on the marathon. Much higher the numbers we talked about last year. Great Job!

By the way, any thought on pure glide plus deadband up hill vs. backing off on uphill to charge the battery plus using EV to minimize the number of ICE startup? I find the latter to be critical in cold weather, but it's not nearly as clear cut in summer. Perhaps I should look into getting one of those nifty scanners...

Andy