I still have to ask my original question. . . "WHY?"


Let's say you drive 10,000 miles a year. If you only get 22 MPG, you will use 455 gallons of fuel. If 93 octane premium costs even $0.75 USD more than regular, that works out to a "savings" of $341 USD/year, or about $7/week.


How can this be worth any risk? There IS a difference to the car, or the manufacturer would not publish their octane requirements. MB has no dog in this race - they do not make a cent if you use premium over regular, but they still say to do so. The engine is designed to use premium, and if you can't afford to use premium, you must have bought the wrong car.

 

Wow, well said. Bold and balsy, but well put.

 

I use Costco gas too, they're top tier so it's fine, plus I save like 30 cents per gallon, considering how my car guzzles gas, I need to save where I can :B

 

Whats wrong with using Costco gas.
Is there any documented findings that it's bad for our W212 engines?
Just curious.

 

Some info from an Costco gas station (employee or manager, or engineer):

Every gas station in the area gets their gas from the same exact source - the only difference is what happens to that gas between the time it is loaded into the 9000 gallon delivery tanker and the time it is pumped into your car.same exact source - the only difference is what happens to that gas between the time it is loaded into the 9000 gallon delivery tanker and the time it is pumped into your car.

Some brands have the load treated right away when it is loaded into the delivery truck. For example, the tanker will be filled with a few gallons of a chemical detergent followed by 8500 gallons or so of gas.

At Costco, we order just standard untreated gasoline. We keep an extra tank of our own detergent underground and the gas is treated at the time of delivery. This allows us to guarantee the quality of our gas - we're not relying on someone else to tell us that our product has been treated to our specification.
Costco gas also tends to be higher quality because of how much we take care of our equipment and care for the product we're selling you. We calibrate our dispensers multiple times a year, despite most jurisdictions only requiring it yearly. Our tanks are inspected weekly to ensure there is no water or sediment in them. Gas flowing into your car is filtered twice to remove any impurities that aren't picked up by the weekly inspections. The process in which the gas enters the tank it has to go through a turbine which has a filter which catches any sediment and we put the additive prior to the driver dropping the load of gas in. Once gas goes through the turbines its filtered once and then flows through double walled piping towards the dispensers. Once at the dispensers it gets filtered again with fuel filter before entering your tank. During the week Costco employees monitor gas flows and it falls below 8 gallons a minute we are required to change the filter in the dispenser. Additionally, Costco takes fuel samples weekly to ensure there has been no phase separation in the fuel.

So...Costco gas is just as good or better than the major brand gas, and at a much better price.

 

Costco has been my gas source for all my cars since they opened near me 10 years ago. Great gas and never a fuel related issue.

 

Good question, I don't know.
Currently, I live 25miles away from costco, so, in my case, it really doesn't matter and I go to BJs for the whole sale priced groceries, which is 4miles away.
I don't have any gripe on Costco gas, it's just that, I thought it is cheap, meaning, quality might be missing.

Regarding testing, as I shared the video link, I would like to invest on the testing, if someone points me to the right direction.
I'll include all the brands, if the test is affordable, for me.

after reading from dchar, I stand corrected about Costco gas

 

You can't go by the compression ratio, because those are mechanical compression ratios that can be and are affected by the valve timing. For example, in the Miller Cycle engines, the intake valve actually closes after piston has traveled quite a bit from its bottom-most position, so the effective compression ratio is significantly lower than the mechanical compression ratio. The W212 engines all have variable valve timing so there is really no set effective compression ratio.

The bottom line is, go by what the MB engineers recommend.

 

Glad you're more informed. Most people don't seem to realize that all gas for a particular region comes from one source. When there's a tanker with 2 million gallons unloading gasoline, it basically goes to all the gas stations in the area, there isn't a separate tanker for brand. And yes, that's basically how it works, all gas in the region comes from the same source and the only difference between brands is their additive package. Some claim to have more detergents than others, but the EPA also mandates a minimum amount in all gas so in theory it shouldn't matter. The only real issue is the ones Costo points out, uncalibrated pumps meaniing you get less of what you pay for and stale gas from low volume places or places that don't check their equipment that often. That's why you're probably fine at any large station that sells lots of gas. I'd worry more at those smaller stations that don't turn over their gas that often. The branded ones could be especially troublesome because several large name brands sold off their gas stations and it's independents that own them and they're at the mercy of corporate who they have to buy gas from and also sets their margins. If they're squeezed, who knows where they're cutting corners.

 

Good to know this information and remove any misconceptions thanks.

I understand, and also, I do go to the stations which is kind of busy, but, left with one empty pump for easy in and out access.
In future, If I live close to Costco, I'll use that.

 

FWIW, I've contacted BJ's just to get some information, this is the reply in the email, from the CSR.

Here is all of the information we have on our gasoline.

Depending on the trade area, BJ's buys unbranded gasoline from many different suppliers, many that are national brand refiners and other smaller independent refiners and suppliers of gasoline. At this point we do not plan on selling Top Tier gasoline. At all times, though, BJ's gas maintains the strict quality guidelines established by the federal government's Environmental Protection Agency (EPA). We sell 87 Octane Regular Unleaded and 93 Octane Premium Unleaded. BJ’s gasoline contains all detergent additives required by EPA guidelines.

The main reason we do not market an 89 octane gasoline is that it would seriously impact our ability to keep prices low for our Members. Eighty-nine octane gasoline has the lowest demand of the three grades traditionally sold in the marketplace, and the cost of setting up a blending system to provide it to our members would be considerable -- ultimately impacting our ability to keep prices low.

BJ's does not currently have any plans to build an E85 gas station as the demand for this product is not high enough to support this type of site. We will continue to monitor the demand for E85 in all of our markets in the event that demand for this product would support such an effort.

BJ's fuel meets or exceeds all federal regulations as to quality and specification. BJ's sites are well maintained and we take extra precautions to ensure that the gasoline going into member's vehicles is of top quality. BJ's fuel meets or exceeds all federal regulations as to quality and specification. It is sourced from major wholesalers and refiners of fuel products in the markets in which BJ's operates.

BJ's gas does not contain MTBE. MTBE has been banned from use because it is extremely toxic. It has since been replaced by ethanol (corn-based fuel), which is also high in octane and oxygen content.

Locations selling ethanol have stickers on the pump stating that the fuel contains ethanol. This means that all grades of fuel contain ethanol. Those Clubs that have ethanol blended gasoline have a maximum of 10% ethanol, as mandated by the federal government's Environmental Protection Agency (EPA).

BJ's stands by its fuel quality which meets the stringent fuel standards set by the EPA and is sourced from reputable suppliers in the market. With reliability in mind, our gas is guaranteed to perform in every automobile's engine, irrespective of make, model or manufacturer. BJ's is committed to Member safety and the environment in every aspect of our gasoline business. Our fuel is guaranteed - this means that if a Member ever has a problem with their vehicle directly related to the purchase of BJ's fuel, we will take care of the problem.

Our sites are well maintained and we use fuel filters to ensure that the gasoline going into member's vehicles is of top quality. We generally use fuel filters that are designed to catch particles or debris larger than 10 microns in diameter. This is very small, or a particle as small as 10 micrometers (about the size of one particle of talcum powder). We also replace filters when flow rates fall below our requirements.

Our filters are also designed to catch water, sediment or phase-separated ethanol / water mixtures.

We have sensors in our tanks (Veeder Root) which continuously monitor underground storage tanks for water. There is no water in the product.

 

I've been using BJ's gas for in my cars for 9 years. Not a problem so far.

 

I actually saw Costco people do this at my local Costco. I also believe that Costco puts its own detergent.

As an aside: I can't put Costco gas in my car cuz it's a diesel (they don't offer that yet). I can tell you, however, that I put in b20 (biodiesel 20% I think) by accident and my mpg on that tank fell to 24mpg (usually we get 29mpg). MB says I can use b20 occasionally but should fill up with regular diesel. I think they were right.

 

Yep. I've had the attendant come up to me before I filled up to ask if I was using Premium. Of course I said yes, so he would stand back with his stopwatch to time the flow rate. I guess they measure for both Regular and Premium.

Costco actually does sell diesel at some locations:
https://m.costco.com/gasoline-diesel.html

 

Here's a recent vid about Top Tier vs non Top Tier. It confirms what some have posted about Costco, etc.
http://www.khou.com/news/local/verif...ter-/455031697

 

I use BP gas 90% of the time but if I'm far away and low, I'll just get whatever is available but I only fill up on BP. And of course I only use 93 at all times.

 

I use gas from the .99 cent store it's mostly watered down so I use it for my yugo.

 

My 2010 recommends 91 octane per Operator's Manual, but in S.C. the octane levels are 87, 89 and 93. When I purchased it in 2009, premium was about 20 cents more per gal. than regular. Now it is often 50 to 70 cents more.
Per MB, you can use 87, but your performance will be slightly lessened (not an issue for me) and your MPG will be slightly lower. I have measured using 89 compared to 93 over long distances - about 2 MPG, maybe.
So, I use 93 if price differential is not too great. I fill at about 1/2 tank and sometimes alternate 89 and 93. Doesn't exactly come out to 91, but fairly close.
I use only Top Tier gasolines, primarily Quik Trip. Visited local tank farm a while back and operator showed me that all the trucks got same fuel, but then some drove by small tanks and "topped off" with additives - this is what made their fuel "Top Tier."
Incidentally saving money on fuel does not mean you bought the wrong car. It means you do not wish to waste money. MB will operate on any octane gasoline without any detrimental effects. MB says so.
Never had a fuel related issue in 14 years and MB dealer has never noted an issue related to fuel.

 

I had an old tank of mixed 2 stroke fuel that i needed to get rid. i added 10gallons to my tank every second fuel up. no issues at all. no smoke no vibrations. i often use 91 or 93, but when the price is over 2$ a litre here in vancouver, i often fill up with 89 or 87, with no issues at all.