This is good to know since I use costco as much as I can thinking that it is better, but my favorite is 76.

 

Cheap gas generally isn't worth the savings. In our SUV, I got 10-20% better MPG with Shell as opposed to gas from random stations (very consistent driving pattern, time of day, traffic-free highway). So that accounts for 35 to 70 cents off per use of a gallon. Now that we've moved back to ND, the only station I've seen positive results in mileage is from a Love's truck stop.

 

I would stay with tier one gasoline for the known detergent additives, etc. which typically aren't found in the "cheaper" fuels. Here is a link to tier one fuels and why you should be using them.

Top Tier Gasoline


TOP TIER Detergent Gasoline Retailers

Gasoline retailers must meet the high TOP TIER standards with all grades of gasoline to be approved by the automakers as providing TOP TIER Detergent Gasoline.

In addition, all gasoline outlets carrying the brand of the approved retailer must meet the TOP TIER standards.

Additional gasoline retailers are added to the TOP TIER list as they meet the standards. The retailers known to be on the TOP TIER list are shown below.

TOP TIER Gasoline Retailers:
USA Canada
76 Stations Chevron Canada
Aloha Petroleum Esso
BP Petro-Canada
Chevron Shell Canada
Conoco
CountryMark
Entec Stations
Exxon
Hawaii Fueling Network (HFN)
Holiday Stationstores, Inc.
Kwik Trip / Kwik Star
MFA Oil Co.
Mileage Stations
Mobil
Ohana Fuels
Phillips 66
Quik Trip
Road Ranger
Scheirl Oil
Shell
Texaco
Tri-Par Oil Co.
U.S. Oil

 

Bp is now Top Tier.

 

Glad to know that. I've been driving by BP and going out of wy way for Top Tier.

 

I was a little up set when I heard because that means there is ethanol of at least 8 percent in all their fuels but with all their problems lately I guess they had too. BP Joins

 

BP has has alcohol in for years, at least in SE Tennessee.

 

Yes in smaller amounts of like 5 percent and or something else. Their gas is still the best around but it was better years ago.

 

top tier is a marketing ploy started by quick-trip to make their gas seem like it was better. Since they had no refineries they needed some gimmick.

Since then it's been taken over by GM, but the site really hasn't improved any. No mention of a 3rd party lab doing analysis or what exactly their standards are.

They do post this on their website now:

It's marketing more than anything. They might be pumping cesspool water and as long as they "attest" to having detergents from a supplier at the advertised amount, they're good to label their product as Top Tier! Hey gonna get me some of that top tier bilge water today!

 

You forgot to mention that one of their requirements for certification is all fuel sold must contain a MINIMUM of 8% Ethanol.

Like all marketing efforts some people actually believe it with no published data or details to back up the hype.

I stopped at a Road Ranger station one time and saw the Top Tier label on the pump. I did not even bother testing their fuel. I just left and went down the street and bought 100% real fuel from a known / verified good retailer. I have never stopped at a Road Ranger station again.

 

As far as Costco being a good fuel, I have learned they get their base fuel from wherever they get it cheaper. I think is just a base fuel with no additives and they have a tank on site that blends the fuel as it is pumped in. The base fuel picks up additives from the tank before if it was dropped with additives and their additive package is registered with the epa but dont think its top tier. The additive package would include xylene and detergents including ethanol. I heard recently it performs as good as the top tier but have no clarification.

 

Gasoline additives fall into 5 general groups. Some additives will be members of more than one group.

Anti-knock (Octane boosters)
Anti-oxidents (fuel stabilizers and metal deactivators)
Detergents
Dyes
Oxygenates (Ethanol)

Xylene / Toluene are sister chemicals to benzene and in most cases can be used in place of each other. They have a higher flash point than base gasoline and because of that can be used as an octane booster. Xylene is also a solvent and will dissolve, as opposed to corrode, some build ups in the fuel system. Is is only slightly corrosive and not as corrosive as ethanol. All gasoline has a small amount of Xylene in it. In higher concentrations Xylene can dissolve some rubber and plastics. Benzine, Toluene, and Xylene are aromatic hydrocarbons that are sometimes referred in the industry as BTX.

So Xylene is usable as a solvent and octane boost additive, but care must be practiced not to add too much. It also does not add any energy to the over all mix so increased mpg or power will not be realized by increasing it's concentration.

 

I notice a 30 mile loss per tank (when the gas light turns on) when I fill up with Costco as compared to 76.

 

I don't know about Cosco but I confirmed something I suspected the other day.

I mainly stick to the big names like Chevron,Shell,76 etc but lately I've been going with the cheapest 87 I can find in my area.

There are a couple of United Oil stations that have the lowest prices and that's what I'm using.I was surprised to see a United oil tanker deliver gas to

a Shell station. I just found out they service both Shell and 76 stations as well as Valero.It's a rip off because I pay $3.48/gal at United and 3.79/gal at Shell for 87 oct

 

Oh, that is VERY interesting. I know Costco says they use a lot more cleaners than any other brand, so I'm thinking it may be what's causing my lower MPG.

I've confirmed this in my families cars: 03 WRX, 01 Impreza, 05 Camry, and 2011 Corolla

 

Costco uses Top Tier Gas you can check them out at www.toptiergas.com
Since March 2014. The same gas as 76, Mobil, Shell and many others that charge much higher price per gallon.
They have the additives that make the gas the best possible. It is not cheap-o gas. It si great gas at a low price.

 

Like he said Costco is now top tier which is good if you got an extra 15 mins too wait for gas hahaha.

 

I've been using Costco and Shell gas for years without an issue. Recently Costco announced higher additives in the gas which may account for less MPG I have noticed in my 2015 Fit CVT. So what I may do is use Shell most of the time and if I happen to be shopping at Costco and need gas I'll fill up there.

Yeah the wait times sucks on Weekends. During the week it's not too bad. Cool that Costco gas stations actually open earlier and close later than the warehouse. It came in handy at times.

 

Now that I have a Costco AMEX card, I generally use nothing else. Not noticed any difference in MPG vs Chevron or Shell in the Fit or Tundra. Only go real early or late, when the warehouse is closed. Otherwise the time wasted in line is not worth the savings.

 

Old school here. In the 80's when I had to put new heads on a Suburu and unleaded fuel was new, my mechanic, who was competent, told me that the new heads were made for unleaded fuel; they had more hardened seats because unleaded was not as kind to valve seats, burned hotter. He also said that burning unleaded premium fuel also helped seats run cooler. I have always run premium unleaded fuel since then. When I had a '87 911 Carrera 3.2 in 2006 the Porsche community master mechanics on Rennlist like Pete Zimmermann said that Chevron Supreme was the only fuel that should go in a 911 and Techron was the only fuel additive I would ever need. I have burned it in everything I own ever since and have never had a fuel related issue since, and I get perfect performance (given that I keep everything else in good tune as well). You guys can save pennies if you want on fuel. And nothing but Mobil1 synthetic lubricants goes into anything I own either, and I change the oil every 3K miles. No oil additives are needed. You can save money on oil also, be my guest. I plan to get 500K - a million miles on my Fit. I'm 69 on June 11 and it's OK with me if the car outlives me.