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Trying to beat my previous MPG record

Discussion in 'Gen 3 Prius Fuel Economy' started by Mark57, Jun 23, 2010.

  1. Mark57

    Mark57 2021 Tesla Model 3 LR AWD

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    We're fortunate to still have a choice of no ethanol in my state. I know most of the country doesn't have that choice.

    The extra weight does make a difference. The trips I've been making with 4 people are killers on mileage although it's still WAY better than what I got before the Prius.;)
     
  2. Tideland Prius

    Tideland Prius Moderator of the North
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    holy.... <bleep>!

    That's 2.9L/100km.. and here I was feeling proud about my new record tank that I achieved today...
     
  3. vday

    vday Member

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    Wish I paid that for a gallon of gas
    Here it is about $6.5:(
     
  4. Mark57

    Mark57 2021 Tesla Model 3 LR AWD

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    You should still feel proud. Consider if I came to your loacation I may not do any better than you and possibly worse. Temperature, terrain, traffic all vary so much it's hard to compare without a level playing field.

    I was wondering when someone would pick up on that. Being that were in the top 5 oil producing states helps keep our prices low. That was $2.68 for no ethanol. The ethanol blend is going for $2.40 per gallon . . . today.
     
  5. PaulHS

    PaulHS Member

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    hmm... an inadvertent pun?

    To your "temperature, terrain, traffic" I would add "technique and tires."

    Mark, I do not mean to offend in any way, but I'm trying to reconcile your fuelly stats with the 70+ mph numbers in your OP. What exactly are you doing to achieve those high numbers, and what's the significance of ~400 mile tanks? (as opposed to full tanks - ~700 miles @ 70 mpg) Are you cherry-picking a route purely to pump up the mileage?
     
  6. Mark57

    Mark57 2021 Tesla Model 3 LR AWD

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    No offense taken. If you read the full thread and replies, you'll see I explained the reason I cut it short. To add detail, since the middle of May, I've been taking care of my Dad in a different city 55 miles away which means I've been required to make high speed trips with the A/C on to take him places, etc sometimes with 4 people on board. These trips come in cycles and at random so it's hard for me to get a length of time free of trips to try something like this. I had an unscheduled trip come up for today so i stopped the test yesterday. I already know what I get on the highway with A/C etc. That's not what i wanted to find out.

    If you read the full thread and replies, you'll see this was a high mileage attempt, any way I could get it as long as it was in excess of 400 miles. I never said I wanted to go 700 miles. that was not the goal. What could I do to beat my previous high mileage mark. That was the goal.

    As to the math, I filled up June 20th mileage 19,060 and again on June 24th mileage 19,478. The trip ODO read 417.8 miles and as you can see the receipt shows 5.471 gallons. 417.8 / 5.471 = 76.366295010053006762931822335953 rounded to 76.4. I see nothing that doesn't reconcile. It is what it is. One minor part I see is Fuelly rounds the trip miles from 417.8 to 418. I have zero control over that.

    No, not particularly but did I AVOID 70 mpg, using the A/C, and hauling 4 people? Um, YES. Did I drive circles in a flat parking lot for 100 miles a day, NO. I drove an approximate route of a ~30 mile rectangle that included flats, hills, curves, traffic, neighborhoods, rural roads at 40 - 55 mph, city streets at 25 mph (OKC speed limit), etc. Did I drive the same route twice, no. Was it scientifically planned and analyzed, no.

    Was I only competing against myself, yes.

    Does anyone besides me think it's legit? Probably not. Did I expect that? Yes.

    Would I love to compete in a monitored sanctioned mileage event somewhere, you bet I would.
     
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  7. Tideland Prius

    Tideland Prius Moderator of the North
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    Fair enough, yes. It's certainly my best distance (even beating the old Prius) but not quite the best mpg (60mpg in the old Prius.. 59mpg right now.. or 57mpg calculated)
     
  8. Mark57

    Mark57 2021 Tesla Model 3 LR AWD

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    I still have to stop and laugh at myself occasionally. You can't complain about 57 mpg which I have in the past. :D Heck I was only getting 21 before the Prius. 57 mpg is still great any way you look at it.;)
     
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  9. tedjohnson

    tedjohnson Member

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    Mine with 2,200 miles on it runs 60 mpg each tank of gas, both calculated and displayed never more than a 1 mpg difference between them. I can not imagine how you can get into the 70's? What tires are you running, what pressure? What tricks have you discovered that others have not ? Details Please :)
     
  10. iceman6969

    iceman6969 New Member

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    Hi there, just got my prius 1 month ago, and started tracking on fuelly, that is where I found this thread. I have averaged 46 mpg on tow tanks without really trying anything special. Just work, leisure, kids, wife, etc. Any basic tips to up this mpg? Tire pressure? how to monitor it better?

    thank you
     
  11. Mark57

    Mark57 2021 Tesla Model 3 LR AWD

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    Hi Ted. It sounds like you're doing very good. My calculated vs HSI display mileage varies up to 5% most of the time. At first I thought it was me. In the past, I've tried filling past the first pump shutoff click to the second shutoff for several tanks in a row but it made no difference in the variation. Now I always stop filling at the first shut off.

    Believe me, 76.4 mpg surprised me as much as anyone. This is not the first time I've tried this although I was a lot more serious about it this time and the weather is a LOT hotter. (94° - 96° today)

    I bought the car last August. It took me a while to learn the best way to drive it thanks to the folks here at P.C. (I'm still learning) By the time I was able to squeeze out a really good mpg run the weather started turning colder forcing me to wait until this year. Then Dad had 4 way heart bypass in May so I've been driving back and forth to his house, doctors, etc., 3 -4 times a week until now.

    My best calculated mileage last year was 3 consecutive tanks between Sept 23 - Oct 6th of 64.6, 62.8, and 65.2 mpg. These were my 7, 8, and 9th tanks in the car. (See my Fuelly details page) One of the things I did back then was I had upped my tire pressure to 37/36 PSI and I started using Neutral gear. If I encounter a downhill section that's fairly long and I have at least 3 bars plus I'm traveling slower than ~44mph (so the ICE does not turn) I'll kick it into Neutral and glide. You can do the same thing without using Neutral but it takes a soft touch. Also, I NEVER use Neutral in traffic. I never pulse and glide in traffic. Safety comes first.

    It warmed up again in November (9th) and I was able to get my best for 2009 at 66.1 mpg. Then my mileage was in the 40 - 50's until this April.

    One thing I did differently this time was I planned it from the start. I started the run from the moment I gassed up. That allowed me to get the high mpg in the first 1/2 mile that many people see and hang onto it. I really didn't expect that. Before, my mpg's would drop into the 50's and then it was a battle for the rest of the tank to bring the average back up. I think that's the key difference. Every inch of the run contributes to the average.

    I wish I had been able to take this run a day or two longer because the average was still going up slowly. Life gets in the way sometimes.

    I have the stock Yokohama AVID S33 tires.

    I use pulse and glide techniques with an eye towards traffic and safety first. I never ever interfere with the traffic flow. My only trick is driving with "gas mileage on the brain" as someone here said once or ten times.

    One other thing to note. We have a lot of wind in OK. Every day of this run we had South winds gusting between 10 and 25 mpg. Yes about 1/4th of each run was into the wind and 1/4th with the wind. Don't discount the other 1/2 had a side wind to contend with as well.

    You'll get there, just give it time.
     
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  12. Mark57

    Mark57 2021 Tesla Model 3 LR AWD

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    Welcome to the forum and to Prius ownership. There's a lot of great information here on the forum pertaining to what you're asking about. There are a lot of people here (most of them) that know a lot more about this than I do. Take a bit of time and read through some of the posts on mileage and you'll see there are multiple thoughts and techniques. One of them will fit you. Some people inflate their tires to what "I" consider an extreme PSI level. I tried that but did not like the ride on our rough potholed streets so I stuck with 37/36 PSI. Also, you're mileage will go up as your new vehicle breaks in and as you get used to it.

    I use the HSI screen to watch my average MPG and enjoy driving it. I coast to stop lights rather than accelerating up to them like non-hybrid drivers do. I also accelerate fairly briskly away form stop lights to get up to speed and then glide at speed. This seems counter intuitive but if you have to use the engine anyway, use it at it's most efficient range. Don't go into the red zone very often. The idea is your engine will run for less time than the amount of time/distance that you glide after the acceleration. Pulling away slowly from a stop uses more energy for a longer period at a less efficient RPM. Try it for a tank or two.

    Enjoy driving your Prius and smile at everyone else because of all the $$ you are saving.

    PS, I stay in ECO mode 99.9999% of the time. I'll hit PWR on the occasional on ramp but not often. If you need it, use it. PWR is fun to use when the occasional snooty BMW pulls up next to you at a stop light. It surprises them every time. :D
     
  13. Downrange

    Downrange Active Member

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    It's 90 per cent terrain. If you live in a flat place, getting better than 60 in the summer should be easy. I have gotten 60 once here in the Appalachians, where every single drive means up and down a 900 foot mountain. That will eat into your mileage, believe me. When I'm in town, puttering around in minor hill country, I can often get into the high 60s. Once coming down the mountain after I filled up in the valley I live in, I pegged it at 99 for a number of miles. I was in the seventies after 55 miles or so, but lost back to the 60s when I had to re-climb that mountain.
    I believe the car is easily capable of 50-55 MPG, just driving it, with only a little bit of attention on "opportunities" to pulse and glide, coast up to traffic lights, etc. The worst tank I've gotten (since buying in April - haven't gotten cold weather yet) was 54 actual, before I learned to drive it the way it was meant to be driven.
    It's a great technical feat, this car.
    And, oh yeah, having a 205 lb passenger definitely makes a noticeable difference. My best runs have been nearly entirely solo tanks.
     
  14. Tideland Prius

    Tideland Prius Moderator of the North
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    lol.. i know what you mean but my previous car was a smart fortwo (and we have a Gen 2 Prius) so my standard are already up there.
     
  15. Mark57

    Mark57 2021 Tesla Model 3 LR AWD

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    90% vehicle? I think that's a bit high while I do agree terrain is everything to mpg's above 65 especially when your talking distances of 400 miles or more. Talk the the other people on this board that have gotten into the high 70's and they'll tell you driving technique is a factor to getting ultra high mpg. Yeah the car is amazing but you must know how to exploit its capabilities to hit the high 70's. If it was 90% the car, that would not explain all the people that live in this "flat" area that can't figure out how to break a 50 mpg average.
     
  16. Mark57

    Mark57 2021 Tesla Model 3 LR AWD

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    I've attached an image downloaded from my Garmin Nuvi data that shows the partial profile of one of the legs I drove. You see the route in feet above sea level as driven on that one day. It ranges from a low of 1,062 ft up to 1,338 ft ASL. Each day was very similar to this route although not exact.

    For those of you that think this drive was in flat as a floor conditions, look at the chart again. Lots of rolling hills. No they aren't Leadville, CO or on the Appalachian trail but it's not flat either.

    Anyway as said before, I was competing against myself in the same area where I had driven my previous best mpg.

    [​IMG]
     
  17. Downrange

    Downrange Active Member

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    Mark, today I went into town, with about 400 miles on the tank, looking at about 59.3 displayed for this tank on the HSI. I picked up a friend and we traveled out from 880' ASL to the Blue Ridge Parkway, where we crested at 2500' ASL. When I got to the crestline, my HSI said 57.2 MPG. A couple of miles of climbing 1600' took more than 2 MPG off the entire 400-plus mile tank. When I went back down the mountain, I eventually got back to 59.1 or so, driving carefully and trying to avoid acceleration wherever I could. Point is, you don't get back what you trade off having to power up significant hills when you go back down them, simply because the energy transfer ratios in/out are not 100 per cent efficient. I'm now trying to get back to the 60 MPG displayed tank I had going around 300 miles into it, but I know I won't be able to get there this tank, unless I do EV circles through the WalMart lot for the next 100 miles.
    Fact is, terrain (not "vehicle," I said "terrain") is a large proportion of the equation, from what I can tell, assuming "perfect driver technique." Maybe 90 per cent is too high. Ambient temperature and fuel makeup is also a huge portion of the equation.
    This means if you live in the flats, you can use optimum driving techniques to get 60-70 pretty easily. I know this because when I have extended periods of driving the flats around here, I see my HSI go way up. That's what I'm trying to say. It's highly terrain dependent.
    Anyway, 76 MPG is an excellent achievement, even in the relative flats of OK. Congrats!
     
  18. hill

    hill High Fiber Member

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    That's about a half tank, right? How'd the other half tank do?
    ;)
    .
     
  19. fuzzy1

    fuzzy1 Senior Member

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    How steep are the downhill portions? I must ask because some of my best MPG round trips, both in the Prius and in previous non-hybrids, include substantial elevation changes, more than your BRP trip.

    My Prius does appear to recover downhill what it took to climb uphill, IF the slope is shallow enough to avoid significant friction and engine braking. Slopes of 1-2% are wonderful, and my other rules of thumb suggest should 3% should also work. But extended downhill slopes of 5-7% require some form of friction braking, killing MPG.

    If you are losing MPG with slopes under 3%, some more hypermiling practice is in order.
     
  20. Downrange

    Downrange Active Member

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    Fuzzy, I think you missed my point. It's energy transfer efficiency that makes it IMPOSSIBLE to recover all the energy expended going up the hill when you go back down it. How efficient is the hybrid system? Maybe 80 per cent? This is physics, not driver technique. I do agree that the ideal hypermile situation is a long, gradual grade, and I have some of those on my route. Unfortunately, you have to go back up them, and those take away a good bit from what you're able to store.
    There is no "free lunch" when it comes to energy in/out systems. All energy transfer/storage systems have loss. That's just the way it is. But the Prius is pretty darned good, which is why we can get 60-75 MPG long term results under ideal conditions.
    The grade was steep and long enough I had to use "B" mode, as the battery filled all the way up very rapidly, and I didn't want to rely or overuse friction brakes. Yeah, it means no energy recovery for that portion.
    The point is that, using optimum hypermile technique, high 60s are fairly easy to get in flat country. It's also possible to get phenomenal mileage (pegged out at 99) by weighting routes to include more downhill, with net elevation losses. The only accurate measure is long term, with start and end points the same elevation, which is why I always fill up at the same station. That way I am sure what I'm measuring. (Pumps differ too.) FWIW, my long term average is around 55 MPG actual, which I'm pretty happy with in this mountainous terrain.