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Comments
Besides, CX-9 is heavy (AWD at 4600lb when loaded with options). 3.7L engine eats more gas than 3.5L/3.6L that most competitors use (Pilot, Highlander).
My CX-9 (after 6000 miles) has been doing 15.5 to 16.5mpg in SF bay area (metropolitan driving). I cruise highway at 75mph, and follow traffic vigorously.
We have the usual traffic jams like everywhere when commuting.
I don't see how people can get 13-14mpg normally.
Maybe,
- check tire pressure
- check alignment
- check air filter for blockage or dirts
The CX-9 is not the only CUV that sucks gas in city driving...I've read similar reports about the Acadia, Highlander, Pilot, and even minivans (my colleague doesn't get better than 20 mpg on his Odyssee). Stop and go driving kills mpg on these puppies, no question about it.
We're not too impressed either, even though we knew mileage wouldn't be too good, you always kinda hope that you'll do better. And when you don't, it sucks. Oh well....
One indicator I use regularly is that when the fuel indicator at the 1/2 mark, if I get 150miles on the trip meter, I will get about 16mpg at the end.
Glad to know the tow package doesn't affect the mileage as we will probably on be towing with it a few times a year but had to have it.
This is the key in calculating MPG.
What the mpg calculator (either on the car or the one in your head) should be figuring is how many miles you drove on the number of gallons you used.
So, if you drove 200 miles since your last fill up and you filled up today and put ten gallons in, you got 20 mpg no matter if there were 2 or 5 gallons left in your gas tank when you pulled into the service station.
Over the years, I have found that the "click-off" point at every pump is different (especially at different stations). You will see some variation with the click-off method when measuring MPG. However, if you do it over a long period of time, it is acurate.
I still don't see what difference filling up with 2.5 or 5 or 10 gallons in the tank has to do with calculating your mileage though.
I have installed a ScanGaugeII on my CX9 for about 1000 miles now. I am here to report my findings. I used the ScanGauge as the trip computer that is missing on our CX9 (the 2009 model shall have it!)
On my CX9 GT AWD (loaded with accessories and options - saved DVD entertainment system), I found that
- it is easy to get 22 mpg with CX9 on highway. On my trip to Sacramento (a bit hilly on some portion of the roads), at 70-75 mph I was able to get 22 mpg w/o much effort.
- it is no so easy to get 15mpg on city that full of lights and stop signs. Unless you can time lights perfectly and acceleration so gently (to the extent that does not piss off your fellow drivers), it would be hard to get 15mpg on this heavy CX9 with short 1st gear (4.15 ratio). With some try and error, I am able to do it now with help of ScanGauge to show me the instant MPG. The idle easy kills the MPG you tried so hard to improve. A red light auto-shutdown and start (like in hybrids) would be nice.
I did try to drive it like what I did to my BMW, I consistently get 10-12mpg on city street. This what a heavy vehicle with short 1st gear can do to your MPG. It revs hard to get you off line (zoom-zoom).
Overall, since my commute is a mix of city and highway, I was getting around 16mpg. With the help of ScanGauge (to change my driving habits), I am consistently getting around 17mpg. As I said, there is not much you need to do on highway other than maintaining constant speed (at whatever you desire). The trick is to be gentle and smart on city streets.
Of course, what I found is not ground breaking. It is all common sense, really. However, if you are getting 13mpg now, you should know what is wrong now....
P.S. I have K&N filer in my airbox. I will change it back to OE filter and see what happen to the MPG.
I have been contemplating purchasing a Scan Gauge II for our CX-9 since it does not have a mileage computer (ridiculous on a $30,000 + vehicle!). Would you say it is worth the money? We recently moved from OH to Eastern PA and even going through the mountains at an average speed of 65 - 70, we averaged close to 26 MPG! We were in SHOCK! Anyway, just wanted to let you know if you do drive with a conscientious effort, it is possible to get noticeably better mileage (~18/19 in city, 24-26 highway). Please let me know about the Scan Gauge.
ScanGaugeII is in short supply now (because it is so popular, thanks to the gas price). Besides the trip computer, you also get the Scan and Gauge. Scan functions to see error codes and look up the codes on internet (hope you never have to use it!) and clear them if you want to.
Gauge functions allow you to monitor many parameters of the vehicles such as coolant temp, battery voltage, on and on. If you are not technology challenged, I bet you would love it. Installation is super easy (Doable in a couple minutes). I put it in from of the "trip meters" (Odometer) with Velcro strips that came with the ScanGuageII.
We all wish that the CX9 came with a trip computer (2009 model will have it), but even if it did, it wouldn't have the extra functions you get from ScanGaugeII.
I am surprised that you got 25-26mpg on highway. I bet you have a FWD.
As I said, CX9 (with 0.36 drag coefficient) is very aerodynamic on highway. One can easily get good mileage on highway if one holds the pedal steady. On city street, you definitely need the help of ScanGaugeII to get better mileage (choose a better commute route, for example). I am getting 1mpg better per tank. That is 7% saving (out of 16mpg). Assuming that I drive 12,000 miles per year. I would need 750 gallon (on @16mpg). 6% of that is 45 gallons. At $4 per gallon, that is a saving of $180 per year. $159 is recovered within 1 year of driving. That is in addition to all the extra gauges and a great diagnostic tool.
Besides, one can use it on all vehicles, not specific to the CX9 (after some initial setup steps for Trip functions).
P.S. I am not a ScanGaugeII salesman
Then, you need to adjust the error of fuel consumption once.
The procedure is to
- fill up at the pump
- drive at least 1/2 tank (I did 3/5)
- check fuel consumed in ScanGaugeII (say 11.4)
- fill up again at the same pump (click-off/top-off), take down reading at the pump
(say, 11.7)
- proceed to adjust the error in ScanGauge (in this case 3%).
From then on, the fuel consumption should be very accurate.
OBDII monitors fuel consumption by injection counts. Therefore, a small error
might be present due to other factors.
It is important to pump gas at the same station and the same pump to eliminate uncontrollable factors. Let it click off 2 times to be sure.
We had a car-top carrier (pushing the 100# total roof-rail capacity), 2 people + 2 big dogs (~ 480# live weight total), plus some additional cargo in the vehicle where we could fit it.
1/2 the trip was freeway, going 75 mph. Got about 21 mpg for that leg.
The other half was non-freeway highway, going about 65 mph. But more passing on 2-lane roads there with often heavy acceleration (it was GREAT for passing). Got about 22-23 mph then.
AC going for 99% of trip.
That was better than I was expecting considering the carrier and total cargo weight.
I'm getting about 17-18 mpg in the car driving solo, mixed 65%35% highway/city driving. That improved from closer to 15-16 mpg earlier in the winter/spring. I also changed the oil to synthetic at 5000 miles (right before the trip).
The car is still under 1000 km so I don't drive it too fast - max. 100 km/h (60 MPH). I am currently quite happy with this MPG, it's similar to what I get on the other car - a toyota camry 1998 V6 3.0L.
<a href="http://www.carspace.com/pirogue/Albums/pirogue's Album/Oct01_0002.jpg/page/photo.html#pic
BTW we love the new car!
http://www.carspace.com/pirogue/Albums/pirogue%27s%20Album/Oct01_0002.jpg/page/p- hoto.html#pic
not sure how to use url function to make address smaller.
In order for the miles/gallons method to be accurate, you have to fill up at the same station and, even better, the same pump between fill-ups.
I have a ScanGaugeII installed and calibrated (with 4.4% error adjustment). So far, it has been very accurate within 0.2 gallons at fill-up (or ~0.2mpg)
I know it is heresy, but comparing it to the Sienna minivan it replaces, the engine needs its revs to move.
It dilutes the error rate. Let's say for example the pump you're using sometimes adds an extra 1/10 of a gallon of gas more or less. Adding that 1/10 of a gallon to a 2.5 gal fillup will create a 4% error (.1 / 2.5 x 100), while that 1/10 gallon pump error will only account for a 1% error on a 10 gal fillup (.1 / 10.0 x 100). Let's say your pump error is 1/2 gal because it's flowing faster or slower, more is released on the click, you're holding the pump slightly differently, etc. That 1/2 gal difference will create a 20% error on a 2.5 gal fillup vs only a 5% error on a 10 gal fillup.
It's basic statistics. The larger the sample size (i.e. the quantity of the fillup) increases accuracy (eg MPG for that fillup).
That's also why scan gauge really isn't accurate for snapshot MPG ratings, since MPG is Miles Per Gallon and if the car only moved a few feet and scan gauge tried to calculate a Miles Per Gallon number based on a few feet of driving, it wouldn't be very accurate in comparison with calulating a MPG over a hundred mile range. So if Scan Gauge calculates that it took 0.023 gal to travel 6ft that would equal 20.24MPG (0.023 x 5280 / 6), but if Scan Gauge was 1/100 of a gallon off and the actual amount used was 0.033 instead of 0.023, then the MPG would actually be 29.04MPG, so by being 1/100th of a gallon off, the MPG inaccuracy was 43% off.
My CX9 GT-AWD played an important role in this. Here is the prelim result.
On a stretch of 2-mile local road w/o light/stop sign.
Each data point was obtained by averaging four data points (back and forth twice to counter slop and wind effect). Vehicle was maintained at target speed with cruise control.
35 40 45 50
---------------------------------------------
40 27.3 26.4 25.4 24.7
35 26.7 26.4 24.8 24.7
30 26.4 24.8 24.5 24.7
25 25.6 24.4 23.7 23.5
20 24.3 22.8 22.8 21.4
--------------------------------------------
^
PSI (all four tires) - warm
As you can see the CX9 is well-capable of doing 27mpg provided that
- run tires at 40 psi (MAX=51psi), it is a bit bumpy...
- maintain speed at 35-40 whenever possible on local roads.
My daughter and I spent the entire afternoon for that data.
BTW, the TPMS lights came on at 20psi (not 25psi or above).
It went away when I pumped them up to 35psi (my typical) and CX9 reached
15mph from start.
Also, a PSI drop of 40/35 down to 20 costs you ~10% drop in MPG.
The MPG was based on my ScanGaugeII, which was +7% compensated.
I have calibrated it for almost 1-year at the pump. It has been very accurate
now (+/- 0.05 gallon error out of 17-18 gallons)
Yes, but basic statistics depends critically on using correct data. The departments of weights and measures in the various states regulate the accuracy of gas pumps to be about 6 cubic inches per 5 gallons. Since there are 231 cubic inches to the gallon, that works out to a relative error of just 0.5% per gallon pumped, not 20%
If one is rounding off their numbers to the nearest 10th of a gallon then one is just being lazy. The price you actually paid for the gas and the posted price per gallon are sufficient to get an appropriately accurate measure of the volume of gasoline that you pumped.
And, speaking of statistics, the "Law of Large Numbers" tells us that whatever errors you incur at each fill up will tend to the correct average over the course of time.
tidester, host
SUVs and Smart Shopper
tidester, host
SUVs and Smart Shopper
It would be interesting (but very timeconsuming) to see measure the accuracy difference by only driving 0.2, 2, and 20 mile lengths.
40 27.3 26.4 25.4 24.7
35 26.7 26.4 24.8 24.7
30 26.4 24.8 24.5 24.7
25 25.6 24.4 23.7 23.5
20 24.3 22.8 22.8 21.4
Correct, but that's only the "fuel actually pumped" vs "what's shown on the gas pump gauge accuracy"
What I'm talking about is the accuracy of person's ability to fill up the tank to the same level every time when they fill up their tank and then calculate their MPG. Even if the pump is 100% accurate, the point at which it clicks and shuts off varies a lot, depending on the speed of the fuel flowing into the tank, position of the nozzle, etc.
Your original question was why it made a difference if you calculated MPG on a 2 gallong vs 20 gallon fillup and that's what I was trying to explain. It's the inaccuracy of the fillup (not the pump) that creates the error, and that error (which relates to the Law Of Large Numbers) will create a larger MPG inaccuracy the less you pump.
Another way to think about it is to imagine if you drove one mile, filled up the tank and calculated MPG. The drive 100 miles, fill up the tank and calculate MPG. Which do you think will provide a more accurate result? Yes, it's an extreme example, but it shows that when trying to increase the accuracy of an MPG calculation it's better to drive more miles.
The four numbers at the first row represents the MPG collected from various speed (35, 40, 45, 50 mph). Each data point is an average of four trials (back and forth twice). The ScanGaugeII computes MPG every 1 second or so. I reset the trip computer at the start and observe the average MPG at the 2-mile end. There are other factors that cause variations more than the ScanGaugeII such as the wind resistance. (on the day of our test, it was pretty windy) I also employed the cruise control to avoid human foot pressure variation on gas pedal.
Actually, that was Steve's question, not mine.
What I'm talking about is the accuracy of person's ability to fill up the tank to the same level every time ...
The information for doing it correctly is available based on what you pay and the price per gallon for your current fill up AND your previous one. Nevertheless, you have a point because most of us are not going to take the extra bookkeeping steps.
tidester, host
SUVs and Smart Shopper
Well, ok, but I live in a perfect world and Tides will vouch that my mpg spreadsheets are accurate out to 9 decimal points. :shades:
Absolutely! But you never did tell me how you measured your fill ups to the nearest molecule or distance travelled to the nearest millimeter! :P
tidester, host
SUVs and Smart Shopper
My basic point was that point and short distances measurements aren't as accurate as those measured over longer distances.
It is interesting how the theory works out. I have a spreadsheet with ~400 tanks over a decade on my minivan and I could delete a few of them and it wouldn't affect the lifetime mpg. At least not out to one decimal point.
Makes you wonder why it wasn't done to the 2010...
Regards,
OW
Just did the same! CX-9 GTAWD/MRB/RLG) for her!
Mazda says fuel saving improvements were a outcome of work done on a model’s AWD differential rigging carryout, engine optimisation for improved explosion control (during deceleration as well as at resting as well as reduction in delivery attrition.
Depending upon various, new 18 as well as 20 in. amalgamate wheels will set a 2011 Mazda CX-9 detached. The brand new alloys are lighter than prior to as well as come wrapped in tyres that suggest improved rolling insurgency (better fuel saving.
Regards,
OW
That is perfectly normal if you know how EPA do the tests.
My wife's Prius gets 33mpg all the time on school routes, which is about 2 miles away with several stop signs and lights.
Take the CX9 on a long trip, you will get 22 mpg AT LEAST!
Further, if you have complaints - point them at the EPA. Mazda did not come up with the numbers, the EPA did.
Today morning with heavy heavy heavy traffic I made 8.9 MPG!!! (26.4 L/100Km - 3.78 Km/L). This last values are horrible numbers.
In the next weeks I will have a highway driving (310 miles) so I will check the MPG consumption in highway.
Some weird stuff I see on the new CX9 2011 is I can go at 40miles x hour and the gearbox is in 6th gear. I read in the past 6th gear is only at highway but seems the new cx9 have a new programming (stupid) because MPG is horrible.