|
OK, here we go - this is a plot of average miles per hour (which is a backhanded way of estimating city vs highway milage) from three MDXs.
As we'd expect, better mileage at higher average speeds (so drive fast!)
I have a 20 mile commute on a 65 mph road with 2 lights (I love it here!!!!) So I spend a lot of time on cruise control, 5th gear, 1800 RPM. But it's cold here, so even at best, I just edge about 20 mpg.
Mogur has a different curve, he really cooks at high average speeds, not so hot when he's cruisin for burgers in town.
kk's got a pretty tight cluster, needs a road trip!
So this looks pretty interesting (well to me, at least)- I think it would be way cool if we had some more points; if anyone else wants to join this data party, check out
http://www.acuramdx.org/forums/show...p?threadid=1035
 |
|
|
|
quote:
Originally posted by ghost
OK, here we go - this is a plot of average miles per hour (which is a backhanded way of estimating city vs highway milage) from three MDXs.
As we'd expect, better mileage at higher average speeds (so drive fast!)
I have a 20 mile commute on a 65 mph road with 2 lights (I love it here!!!!) So I spend a lot of time on cruise control, 5th gear, 1800 RPM. But it's cold here, so even at best, I just edge about 20 mpg.
Mogur has a different curve, he really cooks at high average speeds, not so hot when he's cruisin for burgers in town...
I'll try to get mine for you this weekend. I couldn't get those kinds of numbers if I was towing my MDX!
DBastian |
|
|
|
May get nit-picky on this, but I know on my car with seat heaters, the mileage really drops off when they are on. Curious if the folks who are submitting data are using the heaters much. Same goes for electric defrosters.
I'll be submitting data, if it's still ongoing, when we get our new ride in May sometime. |
|
|
|
| I'm not doubting your report, but I find it very odd that seat heaters, electric defrosters etc, could affect MPG in any possible way? I undestand how an A/C compressor can affect mileage but not electrical accessories. Any Ideas out there? |
|
|
|
Well, TECHNICALLY, the heater or electric defroster put an additional electrical load on the alternator and that adds an additional drag on the engine. However, since both seat heaters on together only pull about 30 amps, that is less that 1/2 horsepower of additional load (1 horsepower is 746 watts in a 100 percent efficent system). The affect at amount of alternator load should be barely measurable at worst.
quote:
Originally posted by msu79gt82
I'm not doubting your report, but I find it very odd that seat heaters, electric defrosters etc, could affect MPG in any possible way? I undestand how an A/C compressor can affect mileage but not electrical accessories. Any Ideas out there?
|
|
|
|
Just a guess, but the seat heaters and maybe the electric defrosters both draw a lot of current as any resistance heating device does. If Redwing's observation is correct then what may be happening is the alternator/generator is engaging creating more load on the engine much the same way the A/C compressor would. I just never figured the alternator would create that much load. I just saw mogur's post before I completed this one so my guess is right.
Anyway I would gladly pay the mpg penalty to keep my buns warm in below zero weather!:eek: |
|
|
|
| I just edited the previous post incorrectly. Sorry |
|
|
|
No problem if one chooses to use the accessory. That's what they are for after all. I live in Michigan and have only a 3 mile ride to work. When I use the seat heater I loose about 2 MPG on a fill up. I admit it might be more noticeable on a higher MPG vehicle ( I get 21- 28 MPGs.) The less MPG one gets, the less noticeable.
For you current owners, a simple test: Keep speed constant on a flat road and engage heater for 10 minutes, then shut it off for 10 minutes. What is the read out on the dispay screen for MPG ( Unless it's not that steady- I don't own a vehicle with instant MPG readout.)
As for as the discussion of horsepower. Wattage is critical and one losses a lot by converting the power to electricity.
Just some of my limited experience. |
|
|
|
Hey all, here's the latest, one new point in the kk cluster, and a sequence from Worm.
I had to extend the X-axis to accommodate some of Worm's data points, he's cruising there at 16 mph in the breakdown lane - think I was behind you the other day :):)
Really interesting thing here, check out how linear Worm's response is - really tight. Also, Worm and Mogur have very similar slopes, mine is quite a bit flatter. Gonna check my tire pressure...
So that's it to date, I know there's others out on this site that HAVE CARS, don't you want another excuse to go out in the garage & mess around in it??
Cheers! :D
 |
|
|
|
quote:
Originally posted by Redwing
No problem if one chooses to use the accessory. That's what they are for after all. I live in Michigan and have only a 3 mile ride to work. When I use the seat heater I loose about 2 MPG on a fill up. I admit it might be more noticeable on a higher MPG vehicle ( I get 21- 28 MPGs.) The less MPG one gets, the less noticeable.
As for as the discussion of horsepower. Wattage is critical and one losses a lot by converting the power to electricity.
Just some of my limited experience.
Wow, I'd never have attributed loss of mileage to electrical stuff - I'll admit to keeping my back end pretty warm up here in northern Minnesota, be interesting to see what happens when we thaw out. Thanks for the post! |
|
|
|
Some data from lwe320 - I'm jealous!
20.3 and 21.4 on your first two tanks of gas - you must be living right!
Don't anyone tell dbastian...
 |
|
|
|
My second and third tank of gas were both right at 21.5 mpg calculated at 65-70mph flat freeway no wind. On the way home I had a real bad headwind and the mpg dropped to something like 18 but I forgot to reset the odo so I cannot tell for sure.
Chris
|
|
|
|
I to was very disappointed with the gas mileage my MDX was giving me. I travel 70 miles round trip per day of which 70% is highway. I was averaging 17.6 miles!
Now after 900 miles of break in (within 2 weeks), today I began to see the results posted on the windo sticker! I average 21.9 miles for the trip into the office today and I did hit 23 miles per gallon during a portion of the trip. All this without having adjusted my air pressure as several of you have suggested. I have no idea what it is but I will check it out after work.
One of you suggested resetting the trip meter so that it is not influenced by the past several trips. I did just that last night and began instantly to see the difference!!! On a short trip to the supermarket I average 19.8.
Just two days ago I ask the dealer about my dissapointing mileage results and they said give it some time before I rushed in to have the car checked out.
Well, have faith and let us know if after about 1500 miles you all have similar experiences. |
|
|
|
quote:
Originally posted by mogur
Well, TECHNICALLY, the heater or electric defroster put an additional electrical load on the alternator and that adds an additional drag on the engine. However, since both seat heaters on together only pull about 30 amps, that is less that 1/2 horsepower of additional load (1 horsepower is 746 watts in a 100 percent efficent system). The affect at amount of alternator load should be barely measurable at worst.
quote:
Originally posted by msu79gt82
I'm not doubting your report, but I find it very odd that seat heaters, electric defrosters etc, could affect MPG in any possible way? I undestand how an A/C compressor can affect mileage but not electrical accessories. Any Ideas out there?
I always thought that the alternator is generating electricity irrespective of the demand, since it is always activated when engine is running. Then the output is modulated based on the demand. I don't see how a seat heater (or any other electrical device for that matter) can put a load on the alternator, let alone to put a drag on the engine...there will always be same drag on the engine, no matter how many appliances are connected. They will each feed from the alternator until its capacity it's reached and then they'll start sharing power or suck it directly from the battery...assuming fuses won't blow out! Unless the engine's rpm is somehow increased to keep up with the increase demand...but this is not an increased load, technically speaking...
That's my understanding, correct me if I'm wrong!
|
|
|
|
Some high mpg's out there! If any of you new folks on the thread would like to end up as a statistic (on this graph), you can post your data, here's how:
--- clipped from previous thread
Next time you're in your car, check your History and drill down into the Details page - there you can pick off the stats your last five fillups. Jot down the miles per gallon and miles per hour, and if you remember, the octane of that tank of gas. For example, my last five were
MPG MPH Octane
18.4 43.7 91
20 54.1 91
16.5 32.6 91
18.6 49.3 90
16.3 35.3 90
--- clipped from previous thread
At some point, I won't be able to keep everyone's ID (I think the limit is 6), but I will find a way to highlight new entries.
I think mileage is related to the volume you play your CD's at... :)
|
|
|
|
Lot's of data coming in - Wen takes the highest mpg prize at 26 mpg, from a 34 mile tank at an average speed of 71 mph, indicating that you get good mileage when you're airborne.
MHarnois has a dead-on linear relationship, pretty much down the center of this emerging cloud of data points.
Finally notice that at an average speed around 32 mph, mpg's range from 16 to 20. At some point here I'll code these points by octane.
Thanks all for contributing - I bet Acura doesn't have data like this! (well, they do now) :cool:
 |
|
|
|
Some new data points from MesaBeige, helping pin down that high end of the curve...
 |
|
|
|
Ghost,
Can't give you any data yet since I only have driven 20 miles on mine and it shows 13.4 mpg. However, looking at your latest graph it appears that mileage is close to linear with speed. I would expect based on increase effect of air drag at higher speeds that the slope of the curve would decline somewhat. Either they lied to us in physics class or we all need to drive faster.:D Another thing to keep in mind is starting June 1, reformulated gasoline will be sold in major metro areas and this might effect the mpg results. |
|
|
|
| Yea, ain't this great? I figure if I can average 100 mph, I'll be getting 40 mpg!! :D:D We need some more folks on the high end of the curve to show us where it levels off - looks like the aerodynamics of that front end really pays off! |
|
|
|
| If your analysis truly shows lineararity. Think of the consequences. If driving faster yields better mpg i.e. less hydrocarbons, CO2 and NOx emissions we can ban all speed limits and create vehicular utopia. Yep, Ghost you may be in line for a Nobel prize by saving the environment and getting us to our destinations faster. You'll have to repaint your Silver MDX Mahogany to symbolize your service to all those rain forests out there. I guess I got a little carried away there, I forgot how mercurial you were!:D:D:D |
|
|
|
I have consistently gotten better mileage than many of the postings here. I often see 23-24 mpg on the open highway. The other day I got the best yet on a stretch of 75 mph highway. It actually got over 26 mpg for a while but dropped back a bit before I could stop and get a picture. Has anyone ever gotten better than this?
(2 passengers - moderate luggage - air conditioner on)
 |
|
|
|
Roadrunner -- those are good numbers, esp @ ~ 60mph avg speed for that pic. Looks to me that MesaBeige is close to that. You in the flatlands? Downhill? Tailwind? Still, good numbers.
Driving to LA and back this weekend so we should have 4 tankfulls and datapoints with speeds above the usual SF Bay Area crawl to report.
BTW, thanks for posting pics of your journey enroute. |
|
|
|
Good numbers, roadrunner, can you dig into your history file and post your recent sets of mph and mpg? You might be the top end of the curve. Wonder if that warm weather has something to do with it?
Also, what octane are you using?
|
|
|
|
| On flat land I usually get just about 24 mpg on Interstates. Out here in the mountains and hills it has been about 21.1 average. I usually use the highest octane available which out here is usually 91. For reasons that make no sense to me, since I always thought gasoline was pretty much the same - I always get 1.5 to 2 mpg better with Shell than with any other name brand gas. Don't know why but that difference has been very consistent. |
|
|
|
| Well, its 1,200 miles later and I'm averaging 15.5 to 18.5 miles per gallon for combine highway/city driving (most 70% highway). Haven/t seen the 19's, 20's etc since that one time. What gives? Even using cruise control the majority of the time. |
|
|
|
...would be to have everyone indicate the level of slopes/hills in their general driving area for which they have given the data above, maybe on a 1-5 scale. 1 could be southern CA (for example) since that area has flat terrain in general. A 5 could be someone in Denver, or Pittsburgh (like myself). I'm trying to explain why at ~32 mph someone has about ~20 mpg, and others have ~16 mpg. It would be interesting to see if people lower mpg are driving in hilly areas, or in wintery condition where the temperature or road conditions might effect mpg. I always average about 1-16 mpg in a mix of city/freeway driving. Only pure freeway gets me to about 20 mpg. I have to blame that on the hilly condition in my area! What do others think....
Thanks,
-S |
|
|
|
Ghost,
Here are 3 more datapoints from a recent trip from SF to LA. Wife did it -- not me, so I'm not certain about the highway/city split; the 1st/2nd datapoints would have included toodling around LA city streets over the weekend.
She said 70-75 most of the way on I-5. The results, to me, were suprisingly low, but she has a habit of driving in D4 all the time since we're usually doing city streets.
18.6 @ 62.2 mph
19.3 @ 49.2 mph
21.0 @ 48.5 mph
Also uncertain of octane used. However, I *can* tell you that the 21 @ 48.5mph datapoint was 92 Shell, since I filled it before she left. I wonder whether she used the cheap stuff along the way! |
|
|
|
quote:
Originally posted by skspgh
...would be to have everyone indicate the level of slopes/hills in their general driving area for which they have given the data above, maybe on a 1-5 scale. 1 could be southern CA (for example) since that area has flat terrain in general. A 5 could be someone in Denver, or Pittsburgh (like myself). I'm trying to explain why at ~32 mph someone has about ~20 mpg, and others have ~16 mpg. It would be interesting to see if people lower mpg are driving in hilly areas, or in wintery condition where the temperature or road conditions might effect mpg. I always average about 1-16 mpg in a mix of city/freeway driving. Only pure freeway gets me to about 20 mpg. I have to blame that on the hilly condition in my area! What do others think....
Thanks,
-S
I can think of a lot of reasons for these ranges, which makes it difficult to factor out a single thing, like octane, for example. One key one would be that at an average speed of 32, there is no way of telling if the car is running at a relatively constant speed of 32, or if it is ranging between 10 and 50 mpg, with lots of city driving involved. (The History file should also report the standard deviation of mph, don't know why Acura left that out...) With average speeds of 60-70 mph, chances are you're not slowing down for nothing!
And, as you mentioned, hills would be a factor, as would wind speed, temperature, and lots of other things. Given enough data, it might be possible to tease out some of these other effects (although right now, octane is the only other thing that folks are consistently reporting.
I'll get this graph updated in the next day or two, been lazy this week... (Actually been coaching a 3rd grade Destination Imagination team, over at last!)
|
|
|
|
Hey all, I've added a few data points, and fit a trend line. Here's how it works:
To predict your mpg, multiply your average mph by 0.1957, and add 11.06. If your actual mpg is more than this, you're above average. If you're actual mpg is less than this, then you're, well, not above average.
This is based on a not-particularly-random sample of 8 above average MDX owners and 41 tanks of gas. Assuming folks pay around $25 per fillup, this is a $1000 study!
This is based on a linear model (which, as Remery mentioned, is going to get me the Nobel prize for energy efficiency) - I'll stick with a linear fit until the data suggest something different.
Of course, the data won't suggest anything different until there's more of it (hint, hint...)
TTFN
 |
|
|
|
Did you also get the octane used with the data collected? It would be nice to see if there was a correlation between MPG and octane. You could also run a multiple regression on the two variables of MPH and Octane. Just an idea.
|
|
|
|
quote:
Originally posted by New MDXer
Did you also get the octane used with the data collected? It would be nice to see if there was a correlation between MPG and octane. You could also run a multiple regression on the two variables of MPH and Octane. Just an idea.
Ghost is doing a bit of pro bono engineering. Doing multiple variable regressions will increase his CPU usage exponentially. Can this forum afford this expense? If we are going to do a more thorough study including octane correlation then I would suggest that some of us, myself included, help "Ghosty the Snowman" up there in the North Country with the analysis.
In my own case, I would be interested in the performance and mileage difference between mid-grade 89 octane and premium grade 93 octane. Also, because of gasoline reformulation requirements in major metro areas, this could affect mileage since oxginated blending components do not carry as much energy per gallon as most typical ones do. This would make it a least a 4 dimensional correlation and temperature affects computer preformance so we'll have to wait a few months before Ghost's computer truly warms up if no one helps him out!! |
|
|
|
We do rely on the heat from our CPU's to keep warm up here, but do like the idea of creating a parallel network of users to crunch all this MDX data.
Plus, I feel sorry for all those 800+ Mhz computers out there spending their lives word processing and surfing the web - computers are happiest when they're cranking out numbers, CPUs in the red zone, running flat out.
So yea, let's figure out an n-dimensional analysis, and put the petal to the metal! :D:D:D
BTW, I smoked a beefed-up wide-tired Chevy truck off the light and heading up a hill yesterday, man was he surprised! Hoo hoo! :cool: |
|
|
|
| P.S. I'm thinking of getting a powder-coated chrome and some pin-striping on my monitor, has anyone tried this? :D: :cool: |
|
|
|
| I would be willing to assist in the analysis. The hard part will be obtain enough data. I have not received my MDX yet When I do, I will collect as much data for this cause as I can. I live in central NY, so the temp and time of year will play a role in MPH. |
|
|
|
Here are more data points:
273mi/16.7mpg/26.8mph - Chevron 92
226mi/16.5mpg/25.9mph - Shell 92
Not looking too good!! :( |
|
|
|
Ghost,
Here's my 1,200 mile report:
219 mi/15.8 mpg/26.1 mph/Shell 93 Octane with ethanol
277 mi/17.0 mpg/31.6 mph/ "
261 mi/16.3 mpg/27.2 mph/ "
220 mi/16.5 mpg/29.8 mph/ "
The last trip was 220.7 miles and with 13.067 gallons yielding a precise mpg of 16.9 so the trip computer appears to be biased on the low side by slightly over 2%. My first tank full calculated out to 17.3 mpg but the trip computer said 15.8 so I ignored that data point. On my trip back from Indiana yesterday, I filled up just before getting on the Tollway. For the 64 mile trip back I averaged 21.7 mpg on the trip computer with a guesstimated average speed between 60-65 mph. However, this is an unaudited result!! |
|
|
|
| Tank 1 = 245 miles, 15.5 MPG (Computer), 15.6 (Calculated) |
|
|
|
Thanks for the notes all, I'm on my own road trip right now, cruising around Clevetown, home of the Rock and Roll Hall of Fame, a tower that is Terminal overlooking a Lake that is Erie, and with a river that, I'm proud to say, hasn't caught fire in quite some time now!
We'll return to our regularly scheduled mileage reports next week, so keep'em coming!
Hey, it's green here, what a concept!
Rem, swung around Chicago like a starship slinging around the sun for centrifigul force, maybe I can bring you that cup of coffee on the flip side.,, |
|
|
|
Here are my figures after the first 5 tanks. Most of my driving is in southern Wisconsin on relatively flat terrain but in moderately cold weather. All figures are a combination of highway/city driving, about 60/40. All fuel is 93 octane Amoco.
19.88 mpg calculated, 19.4 mpg computer, 29.9 mph
20.57 calculated, 21.1 computer, 42.3 mph
20.48 calculated, 21.3 computer, 43.2 mph
20.89 calculated, 21.1 computer, 46.2 mph
23.03 calculated, 21.8 computer, 38.4 mph
|
|
|
|
quote:
Originally posted by ghost
Rem, swung around Chicago like a starship slinging around the sun for centrifigul force, maybe I can bring you that cup of coffee on the flip side.,,
You might not want to come through Chi Town, it snowed last night and that's a bit of deja vu you might not want to endure. However, there are always the MDX bun warmers so stop by cause my mug waiteth!!:D |
|
|
|
I hope this thread isn't all worn out yet before I get my $0.02 in.
I have a friend (cough, cough) who regularly gets 19 on the nav while travelling long trips at a steady 90 mph.
That would be while using 93 octane, with 8500 miles on it.
I am guessing that the wind resistance must start to level it off around there. |
|
|
|
quote:
Originally posted by Crem de la SUV
[deleted...]I am guessing that the wind resistance must start to level it off around there.
What are you referring to when you write "it"? MPH? MPG? Resistance? |
|
|
|
| Tank 2 = 266 miles, 17.8 MPG (Computer), 17.4 (Calculated) |
|
|
|
quote:
Originally posted by Crem de la SUV
I hope this thread isn't all worn out yet before I get my $0.02 in.
I have a friend (cough, cough) who regularly gets 19 on the nav while travelling long trips at a steady 90 mph.
That would be while using 93 octane, with 8500 miles on it.
I am guessing that the wind resistance must start to level it off around there.
Still plenty of room on this thread which is actually turning into ghost's research project. In my own brief history, at 80 mph and 93 octane gasoline I got the instantaneous mpg to level out at 21.7 with 1,200 miles on my rig. I think there is some room for improvement once you get over your cough!:D:D |
|
|
|
quote:
Originally posted by wen
quote:
Originally posted by Crem de la SUV
[deleted...]I am guessing that the wind resistance must start to level it off around there.
What are you referring to when you write "it"? MPH? MPG? Resistance?
I am guessing the wind resistance begins to become more of a factor, negating further MPG increase.
My figure is lower than others, since I do not drive a steady pace; I would, but need to slow down frequently for those who are misusing the passing lane.
I think I see the best fuel economy at about 80 mph. |
|
|
|
Interesting incident last night with the Touring Package A/C-Trip feature (not sure if the base has this or not).
As many of you know I help coach a nationally ranked U13 baseball team and am extremely careful/cautious when parking at ballfields:grin:. Last night the only parking far enough away from foul balls was on a narrow street with very steep banks. Parked on the left side (facing traffic) with the passenger two wheels barely on the pavement. Thus the driver side wheels on grass down the embankment. Due to the steep incline the car was sitting at quit an angle.
Low and behold when we cranked up to leave, the computer said we just got a new tank of gas! Yep, reset the trip history automatically. I suppose the reset feature is tied to a fuel level indicator near the top of the tank, which was triggered due to the cars incline. |
|
|
|
