Maybe I'm way off base here, but I made a post in the MPG thread a while ago about how my '11 OS has been getting horrible mileage since I've owned it. I've had my OS since November 2011, it has about 27,000 Miles on it, everything is stock, I don't have a heavy foot, but I've averaged about 22-23mpg for the life of the car and I just chalked it up to the fact that I live in a mountain town with thin air and lots of hills.

Now for the interesting part: as long as I've owned my car, I've filled it with Chevron 85 octane fuel because I have a gas card that saves me 10 cents/gallon every time I fill up there. However, yesterday afternoon I filled up at a Shell station with regular 85 octane in preparation for a long, 1.5 hour trip. The station was close to the freeway and I was low on gas, so I just went there and paid the extra 25 cents/gallon over my regular station. I've filled up at other stations before, but never really noticed a difference in fuel economy so I wasn't really expecting anything to change on this trip.

This is a trip I make at least once every two months. It's about 100 miles and involves a freeway with lots of ups and downs and a 20 minute drive up a canyon pass at 60mph. Every time I've made this trip I go about 70mph for the first half and 75 for the second half, save for the canyon pass. I take it in 2wd mode, cruse control most of the time, AC is usually on and I average about 23-24mpg the entire way. I've never completed the trip with more than a half tank once I return home. Last night, same trip, same drive mode, cruise on, AC cranked up to 4 notches in 95 degree weather and I somehow averaged 27.5mpg and made it back home having only used 1/4 tank. I thought maybe this was just a fluke or that I had changed my driving style, until earlier this morning. I had to make a pretty grueling commute through residential neighborhoods and slow highways with lots of stop and go this morning, plus an extra stop at starbucks. The kind of trip that usually gets me about 20mpg and drains my fuel tank like it's leaking. Today, by the time I got to where I was going my trip computer said I was averaging 28.1mpg and my fuel tank is still 2/3 full. I don't know whether Shell has a particularly good batch of fuel, or if my car finally decided to get the advertised fuel economy, but I'm very happy with the fact that it's been doing so well and I don't think I'll be filling up at Chevron anymore.

Has anyone experienced anything like this before? I can't be the only one

 

This is something you should take note of - gas from different stations.

I have relatives who owned gas stations and there's definitely a difference in the care it took to maintain their underground tanks >

Checking And correcting for moisture/water in those tanks. (How often, if any.)

OR, the fact that they (the station itself Or the delivery tanker) may be selling/supplying LESS than advertised Octane to their customers.

So, if you really want to be sure - keep track of the MPGs you're now getting with the gas purchased from that Shell station (or similar).


You can ask the station which delivery company or how often they receive a tanker, so you know when you'll pump the "freshest" batch of fuel.

 

I noticed you said you are running 85 octane. Is it E-85? I never knew the OS was rated for 85, unless it is something in Canada? THis is something new to me.

However, on the part of fuel... The ethanol in fuel contributes to a loss in MPG. Not simply because of the ethanol, but because sometimes the ethanol can become separated from the fuel. I have seen cases where the fuel we Soldiers get on base from AAFES causes problems with vehicles and produces poor mileage. I had a 2012 Toyota Tacoma crew cab with the V6. I was getting atrocious mileage (16 MPG) when 20 was the advertised (still too low for me). I also felt the engine wasn't producing the power it should. I took it in to a Toyota dealer when I was in a course in Arizona and had them hook it up and run emission and engine tests on it. They found nothing. But while it was in, they had several other brand new Toyotas coming in with engine problems (02 sensors corrupted, engine lock up, etc.) So they hooked them up. Nothing.

After it all boiled down, the common denominator was FUEL. We all bought fuel from AAFES on base. It was serendipity that a rep was there from the regional office and had a bottle of fuel additive in his vehicle. They tried it in one of the Camrys and voila! Problem solved. They found that the ethanol was separating from the fuel and was tearing up the emissions systems causing the ECU to freak.

So, my recommendation would be to fill up using your card at your regular station, but buy a couple of bottle of a good octane booster or fuel treatment and see if it helps. If it does, then you have your solution- bad gas at your local station.

You can test it yourself by syphoning a small bit of fuel after you fill up before adding the additive and putting it in a glass mason jar. If you see separation, put in some of the additive and you should see the fuel come back together.

On a side note, you really aren't saving much by getting the fule at .25 cheaper. On 10 gallons its only a savings of 2.50. Its the big shiny orb principle/ Stations and retailers flash savings convincing you to buy more products to get savings on what hits everyone the hardest- fuel. Then you only save 2-3.00 on a tank. You could save that and buy a higher octane. Just my two cents.

 

Sorry, I should explain the octane rating. I was told a few years ago that Utah uses a different type of rating, so what's typically regular 87 Octane fuel in the rest of the country is rated at 85 for us. Same with Premium, what you'll see as 93 in CA or other states is rated at 91 in Utah. There was a big blow up on a local motorsports forum about the fact that Utah doesn't get 93 octane fuel and somebody who was familiar with the measurement system we use had to explain it to everyone. So our 85-octane is the same as 87 everywhere else, there's just a different set of weights and measurements that our state uses for some stupid reason.

That being said, though, a lot of the stations I've seen in this state have a disclaimer saying that their fuel contains 10% ethanol, so that may be a contributor to my bad mileage!

 

This is extremely helpful. I'll see how long this tank lasts me and try to fill up at the same Shell station on the same day of the week. Typically I only get about 230-240 miles on one tank, so if I can increase that by filling up at this station it will be worth the extra few cents per gallon.

 

^
Ok.
You should see about 350 to 400-ish+ easy (once you figure out) when fuel is not the problem.

Good luck.

 

It's been about two weeks...
Out of curiousity, have you notice any changes/improvement in your MPGs with the different fuel?

 

Ok, sorry about the late response. It seems that the two 28mpg trips were just a fluke. After those two days, I returned to getting about 21-22mpg and the tank ended up lasting me about 340 miles. I've filled up 3 times all at different stations with different grades of fuel and every tank has averaged around 21.5mpg.

I'm honestly considering trading this car in for something else. I bought it for the sole reason that it has AWD and I could expect 26mpg, but I'm finding out more and more people are averaging closer to 22mpg. With that kind of mileage I could be driving an EVO or WRX and having a lot more fun with it.

 

hmm..
If you're seriously looking at EVOs or WRXs, then perhaps you can step up to a Mazda CX-5 (35MPG Hwy) or BMW X3 (28MPG Hwy) to keep the "room" and get some more performance. Just a thought..

 

I'm considering a CX-5 2.5L, probably won't get much better mileage than the OS but at least it won't feel like my tires are glued to the ground when I get on the gas. Only reason I'd consider a wrx or evo/ralliart is because that's what I was looking for when I ended up buying the OS. Had my eyes on a 2010 ralliart w/20k miles and the OS was only a few thousand more brand new and gas mileage was a huge concern at the time. I'm starting to realize I probably would have been happier with the ralliart and a Cobb AP that I could switch between economy and performance tunes.

 

BMW X1 starts only a few hundred dollars more than the CX-5...

CX-5: $29,665
X1: $30,800 RWD, $32,500 AWD

CX-5: 184HP/185TQ 2.5L 4 Cyl
X1: 240HP/250TQ 2.0L Turbocharged 4 Cyl

CX-5: 24Cty/30Hwy & 26 Combined
X1 RWD: 24Cty/34Hwy & 27 Combined
X1 AWD: 22Cty/33Hwy & 26 Combined



I imagine 240HP/250TQ would be plenty fun in a compact SUV (hint, hint ).




And if any one was wondering, I want one.

 

This is all false. 93 is 93 everywhere. 91 is 91 everywhere, and so on and so forth. You might not have 93. CA, AZ, and NM generally only go as high as 91. Whoever told you this nonsense should be slapped a few times for making all that up.

 

I had wondered the same thing when OP posted his statement about octane in his area, but since I never been to (or live near) Utah I had no way of countering his comment on how that state mixed their fuel.

Good to know I wasn't crazy to suspect otherwise.

 

Yeah, you're right. I probably shouldn't have just taken the word of some forum troll from 5 years ago A quick google search lead me to an article that says Utah and Colorado sell lower octane fuel because it's less volatile at higher altitudes. I guess thinner air means less risk of knocking.

 

I believe that's correct.


I did consider a Subaru Forester XT 2.0Turbo CVT, for a time.
Horsepower (hp): 250 @ 5600 rpm
Torque (lb-ft): 258 @ 2000-4800 rpm

But, I just couldn't see myself chewing on $36,220 price tag...