Document your MPG by doing this!

How is it that this fuel economy thread has evolved into an argument over published works, credentials, and formulas of queueing theory. Who cares, that's what Fred's House of Pancakes is for. We don't need all this here. I'm getting the idea that a Nouveau Member just likes to piss people off (from reading previous and current posts).

 

Sorry, my bad. I will try harder to avoid feeding the trolls.

 

I wasn't the one who came into the thread and said "I am quite familiar with the subject, why don't you whip out a bunch of formulas that no one will understand but me". I'm not biting the bait, because I know someone's just trying to start a d*ck measuring contest.

If by "piss people off" you mean "calling BS when he sees it", then sure. But if you're happy believing half-baked theories, feel free to ignore me. I believe it's free to use that feature.

 

And we continue to digress.

 

FWIW, I have been hypermiling for the last two tanks. Both tanks came in over EPA estimates with no problem. As stated above the only thing I am doing is running air pressure at 42 Front 40 Back, limiting A/C usage and utilizing P&G when I can.

Last tank was 52 MPG by the pump and the fill today was 51 MPG. Those are actual figures using gas pump figures and miles travelled. I understand the bladder changes with temps, but right now the temps have been about the same. I also used the same pump for both fills.

Take a look at the fuelly site to see the actual mileage since I started hypermiling.

Edit: Just changed over to Mobil 1, so I am looking for better numbers soon. I was running dino oil.

Happy driving everyone

Ron (dorunron)

 

Good job Ron! It'll get even better when temps drop enough for you to turn off the AC.

 

this is mine.

 

Very impressive boppo!

 

Here is a update on my MPG progress. I did a short fill tonight as I am going on a road trip tomorrow and wanted a full tank. Either I got excellent mileage since I changed to Mobil 1 and virtually eliminated the A/C, or else the bladder fooled me on the short fill. To make a long story short 67.0 MPG on the last fill. The MFD was showing 59.7 when I did the short fill. 80% Hwy, 20% City next tank, so I expect something around 45 or better. More later...

Ron

 

The MFD is usually within 2%. Hand calculations can be all over the board so I just go with the MFD and minus 2%.

 

Agreed, I do a overall average, but do watch my usage from tank to tank also. That is why Fuelly.com really helps with keeping a good log. My number's could well be off due to the bladder. I should be able to tell by the next couple of fills, but I am making progress...

 

You're doing good Ron. What is your highway speed? With 80% hwy, I would be hard pressed to get 60+mpgs unless my speed was 55-60mph. I am also learning how to hypermile my route better all the time. I find it fun but sometimes exhausting. I have been riding my motorcycle (gas guzzler) more lately with the mild weather and I'm only getting 46 mpg on that (2007 Suzuki Hayabusa).

 

I tend to hold my hwy. speeds down to 62 max. I usually average 42-45 with dino oil and A/C runnng. I am hoping to see upper 40's on this trip since I changed to Mobil 1. Halfway thru the trip at this time, MFD is reading 50.1, based on what I am seeing I estimate upper 40's for the trip. Until I got into East Texas where the hills are, the MFD was reading 53.

I used to ride a Honda Shadow, as long as I kept it under 70, I could get 50 MPG out of that also.

To make a long story short, A/C usage in the Prius definitely affects the MPG, so if you are interested in maximum MPG, limit or eliminate the A/C. The tire pressure 42F/40R helps, but the A/C is the kicker imo. P&G also helps dramatically, but you have to stay on top of it and alert at all times to traffic conditions along with the topography of the roads to maximize that way also.

Ron

 

I sold my Gen II 39 months ago, so I don't have up-to-date pictures from that car. In fact, I don't have many pics I ever took of the display. Still, I managed to keep a couple around.

To be fair, the ones I was most interested in were the high numbers, not the low, certainly not the "average" ones. At the same time, I logged every fill-up, as I've done with my Gen III. In my signature, you'll find the real info that covers every mile, every reading from the MID/MFD, every piece of data I gleaned from both cars. My real-life calculated mileage for the Gen III is down to 49.8 MPG after close to 59,000 miles. I'll also look to see what I had for the Gen II.

(There are several threads about the differences between the MID/MFD readings and calculated MPGs. The most comprehensive one is a sticky worth viewing under the Gen III Forums.)

I don't hypermile. I live in the Midwest, and I contend with very cold winters and very hot, humid summers. I use the A/C.

My commute is very short, but I put miles on by driving around to visit clients and for family vacations and weekend getaways. My average mph is low, mainly because I'm driving around town all of the time, and I meet stop signs and stop lights (and I tend to obey the signals).

For my Gen III I have separated out City miles from Highway miles, but I can't recall whether I did this for my Gen II. I'll go check my records to see if I can come up with a breakdown.

In any event, here is a pic from a tank many years ago from by 2007:

 

Update (of sorts):

I found my old spreadsheet where I kept all of the records from my Gen II. I was surprised by the number of 60+ MPG tanks I had. The Gen III may be a better car in many ways, with even better fuel economy, but when you add the larger, heavier wheels and the other ATP weight, my Gen III doesn't perform better than my Gen II. NO COMPLAINTS -- I'm happier with my 2010 than my 2007. I can give up 2-3 MPG for the creature comforts, ride and handling upgrades -- not to mention the additional space and better styling!

My MFD/MID data for the Gen II showed a lifetime of 52.2 MPG. I tracked a rolling 12-month trend, and when I sold the car I believed that was a better measure of the fuel economy, because the lifetime covered more cold months than warm months. The rolling 12-month at the time I sold the car was 53.4 MPG. I had a strong string of fill-ups in 2008 worth noting. Though I couldn't quite make it over the 60.0 MPG hump for a long period, for eight consecutive tanks, totalling 3,804 miles, I averaged 59.5 MPG, with a high tank of 61.3 and a low tank of 56.7. That was some pretty high performance. In those days, I was really trying to get high MPGs, but I still wasn't hypermiling. I was driving on highways at regular speeds and still driving to work and around town. This was a stretch of regular life, not just a couple of "special event" tanks.

In terms of the difference between the MFD/MID and the calculated mileage, the Gen II doesn't show the kind of variance which appears in the Gen III. My lifetime difference measured at 2.64%, meaning the lifetime MFD/MID display information was 2.64% higher than the calculated mileage. As an example, following the same eight consecutive tank fills noted above, I measured (calculated) an average fuel economy for the same 3,804 miles of 58.2 MPG. My high measured tank in that group was 64.4 MPG, while the low was 54.6 MPG.

To see how different things are with the Gen III, please take a look at this thread: calculated vs. computer MPG - Please post your results. My up-to-date summary is shown in this post on that thread.

 

It's the 17" wheels killing your mileage.

 

No doubt!! The teenager may not be helping things of late. Also, driving my son and his friends to and from baseball, football and basketball games isn't getting any easier. They are all getting to be so big, and they bring heavy equipment.

 

That'll do it. In fact, I'm surprised your mpg is so good considering.

 

Talent. Pure, unadulterated talent. OR:
Skill. Finely honed skill. OR:
Horse hockey

 

In reference to post #129 above, I have determined that the bladder fooled me. I should have known better. This is the second time I have seen this pattern. Normally, the mileage comes in around 45 to 48 with dino oil unless I use excessive A/C while being parked in ready mode. Two times now, including the short fill I referenced above, the high MPG tank was followed by a low MPG tank and at both instances, the MFD reading were not correlating with the pump figures. For the most part, the MFD is accurate, however it does tend to read higher than actual mileage. MFD variation has been discussed many times and it seems all agree that the MFD tends to read 2 to 3 percent higher than actual mileage at the pump. As F8L stated, one tank MPG average on the Gen II does not mean anything. You have to average several tanks together to get an accurate measurement.

Before using Fuelly.com I ran a spread sheet comparing MFD averages to Pump averages and found overall the figures were close enough, not perfect but close enough to show a basic average. Over a four month span of time, the MPG average at the pump was 46.62 and the MFD average was 48.7

Unless I see a dramatic difference over time since I switched to Mobil 1, more than likely I will not post any more in this section of the forum. For the record, after the road trip, the MFD was reading 49.6 @ 332 miles and the pump average was 43.9.

When the bladder expands normally, if the MFD reads something like 50, the pump average is usually around 47 or 48.

Ron