Same Brand of Gas, Same Octane, Different Gas Station and Different MPG
 

So 2 weeks ago I went to fill up my 2012 TL with Shell V Power 91 Octane Gas. I used to fill up with 76 but my usual gas station ran out of Premium. So no choice I drove down the street and fill it up with Shell. I typically gets about 19.5~20.3 MPG on 76. But after filling up with Shell, I was averaging about 22.5~23.8 MPG. So I was pretty impressed by it. Then last week I fill up Shell again because I was impress with the MPG BUT this time at a different gas station. After filling it up, I was getting about 20 or so MPG. Then next day, as I was driving to my office, my MPG started to drop to about the average of 18.5 MPG. So I was thinking, would the same brand of gas with the same octane but at a different gas station makes a difference? My driving habit this month has been very conservative since gas has peaks its all time high in California. I would average my freeway speed at 70MPH and below 2000 RPM. I recalled my average is about 21 combine freeway and local on the first time filling it up with Shell gasoline. The second time I filled up with Shell at a different gas station I was averaging 18.5 combine freeway and local.

So just like to see if anyone experience a sudden change of MPG using the same branded gas but at a different gas station. And hope you can give me some feed back.

I think after my tank are empty, I should go back to my first fill up at the original Shell gas station and see if there are a difference.

Ive seen mine fluctuate anywhere from 24-27, but I also have to factor in other variables such as weather, and where I am driving. Typically if I do nothing but highway on a tank it will stay consistent regardless where I get gas from.

Although it wouldnt surprise me...

way to many variables going on to be able to really determine if it's the gas

^ :werd:

I'll move this to the 4G TL section as well so other TL owners can chime in with their experiences...

Few quick thoughts. The numbers on the pump are not absolute ratings but minimum ratings so the true octane can vary tanker shipment to tanker shipment. The mix of ethanol in the gas also is not absolute but is described as "up to" 10%. Also you have some gas left in the tank from you last fill which mixes in & changes one way or another what is being pumped.

I mix 93/100 50/50% in my car & my motor logs show differences tank full to tank full even though I generally fill at 1/4 tank left.

By the way I am good for 20+ in Raleigh & 30+ on the interstate @ 375whp/430chp.

This^

I've used both. Although I've never seen a specific mpg difference. I'm such a hot foot that my mpg's are always crappy. Now I primarily only use 76 gas because it is more reliable. I also save my gas receipts for an entire tank just-in-case there is an issue.

I don't pay any attention to that. I fill my tank every 4 days and roughly I get 300 miles with stop and go in traffic.

I'm like half highway and half local when I go to work and on a full tank I would get 389-395 average and I usually fill it up once a week and very conservative as far as how I've been driving these pass month or so with price on fuel going up.

Hey Ray, also keep in mind the AWD is slight heavier than the FWD it will give more MPG

Good chance that the ethanol mix percentage could be the culprit. It wouldn't take much of a difference to cause the mileage variation that you are seeing.

Used to happen to me all the time on my 02 TL-S. 91 octane Shell from 3 differenct gas stations gave me 3 different mpg's.

We'll see what happens on the '12.

You should try to mix half a tank from shell (V-power) and half a tank from Chevron (techron). this will give you V-tec gas. That works best for me.....LOL JK....

I used to get gas from all over the place when i first got my car but After getting shell/chevron I did notice a small increase in MPGs I think you might be onto something OP.

OP, are you from Cal? I think the state of California just switched to winter-blend gas. There's a slight difference between conventional summer and winter-blend gas. It has something to do with the Reid Vapor Pressure of the fuel (volatility of a gasoline). The summer blend has a low RVP and is less likely to evaporate compared to the high RVP winter grade.The summer-blend gasoline contains more energy than winter-blend gas so you'd notice the difference in hp too.

I agree 150% with you!! There is NO way that you could recreate the EXACT same condition to ascertain this claim....

^ At least quote the MID's average MPH value in addition to the MPG that everyone likes to quote. I'm sure there would be a difference with those MPH values between tanks. It's very hard to equate the same tank- for one the OP bought gas from different stations so at least the first few miles are going to be different.

I get very consistent MPG from the same brand gas from the same gas station- the difference is always with the MPH. It might range from 24MPH to 29MPH depending on how many highway miles I have which is not a lot.

When I first got my 2014 TL 3.5 I was putting Sunoco 93 gas since it closest to me and I was getting 20 mpg I do 80% city 20% Highway
Then I started filling with shell 93 and my gas mileage went down I was getting 17 sometimes 16 mpg same drive and same route
I just switched back to Sunoco 93 again and gas mileage went back to 20 mpg
I don’t understand it since shell 93 V-power is supposed to be one of the best gas to get 🤷‍♂️
I only had the car 2 years and I haven’t tried any other Gas except them 2 since they’re the closest tier 1 gas stations near me

Frankyy, You don't need to run 93 octane in your car (unless you've done a ton of performance mods). From the factory your engine was designed to run well on 91 and bumping up to 93 will do little/nothing for you. Save some money, and you shouldn't see any meaningful performance change (up OR down). As far as your mileage it seems a bit low in your base case. I had a 2013 TL (bought new) and my base case (70% city/30% highway) gave me approx 25 mpg all in. On purely highway road trips I easily beat 30 mpg, giving me an effective range of 450+. Given some of your prior posts it appears that you are dialed in to upkeep/maintenance so its a mystery as to "why" your mileage is so low.

Some states don't have 91, just 87, 89 or 93 like in FL.

I record every single gas purchases since mid 2011 on my 2010 TL. I mainly purchased at Costco, Kroger, and occasionally Shell/BP. I couldn't detect any difference in terms of performance and mpg. I regularly get 30mpg on highways, and 20mpg in city.

I use Sam's Club and Casey's gas in Oklahoma. I get 23.5 in suburban type driving and almost 30 mpg at 80 mph on a long distance trip. I'm pretty happy with having a car that gets this kind of mileage with almost 300 hp under the hood.