listerone

93 is what you see here.I think it's an East Coast/West Coast thing.

hyperion667

I do have 93.....I rotate between a few places and noticed while filling up my TT that is was indeed 93

K-A

Most Lease these cars for discounted deals approaching what an un-subsidized $35-40K car would cost though.

J Dubya

Oklahoma is goofy. Here in Tulsa, we have 87, 89 & 91 corn and non corn (which I only use) and down the road 100 miles in OKC, there are more than several stations that have 87, 89, 91 & 93 all non corn.

Tulsa used to have 93 about 10 years ago.

mleskovar

No increase in hp by using higher than 91 octane and no damage to engine by using lower. Using lower octane just reduces the hp and it's not significant although some will notice it. However....if you expect the same performance from your car with lower octane and put your foot in to match the higher octane performance you'll reduce the gas mileage. I don't know where the trade off is "Being able to afford premium if you own a Benz" makes me chuckle. Do you know what kind of car Warren Buffet drives? Or the president of Ikea?

Higgs Boson

bahaha you peeps in california need to get out more. 93 exists in the states, it's all we have in texas (except for high altitude el paso).... it is also in most states. the only states with 91 are high altitude mountain areas and epa loving cali. some of the east coast states even pump 94.

regarding whether 91 or 93 makes a difference, yes it does. I tune ecu's and going from 87 to 91 to 93 each has a substantial impact on how much timing the car can run (and not retard away from spark knock) and therefor how much throttle response and overall power it makes, not to mention fuel economy. of course, if the most advanced timing maps are tuned to 91, it won't do you any good to run 93. but if they are designed around 93 then you will be missing out using 91.

with that said, pump gas is so terrible and inconsistent that running a certain octane doesn't mean you will always be getting a quality 91....running 93 can help alleviate the effects of the odd tank and prevent the ecu from pulling timing. of course, running 110 octane race gas in a street car is much different. total waste.

mleskovar

The ecu map can only tune down. So unless you have a tune you're wasting money buying 93. My last Benz had several standard levels of tune that could be accessed. I don't know if using 93 was one of them or not. The thinking on the levels of tune was if you were in a location that didn't have access to 91 you could still run at peak efficiency for what was available. During the gas crisis people were requesting a drop in tune to save money and they claimed they couldn't tell the difference when commuting.

BenzE350

I just read something interesting in Wikipedia regarding octane and storage tanks. I did not know this. Makes me question if I can getting the 91 octane I am paying for? Probably depends on how often the inspectors pay a visit to the station.

FROM WIKIPEDIA:
Most fuel filling stations have two storage tanks (even those offering 3 or 4 octane levels): those motorists who purchase intermediate grade fuels are given a mixture of higher and lower octane fuels. "Premium" grade is fuel of higher octane, and the minimum grade sold is fuel of lower octane. Purchasing 91 octane fuel (where offered) simply means that more fuel of higher octane is blended with commensurately less fuel of lower octane, than when purchasing a lower grade. The detergents and other additives in the fuel are often, but not always, identical.

Live Oak

In the good old days (you remember those, right? The 1960's and 1970's when gas was 24 cents a gallon) all you needed to change your timing was a 3/8" wrench and a cheap timing light.

A big Ford 460 V8 was set up to run on regular. However, if you were at high elevation like 5,000+ ft. (it's elevation for cars, not altitude) the car was really weak, a dud because it was gasping for oxygen, but you didn't know any better.

With premium gas, you could crank up the ignition advance a few notches BTDC and give the car a real kick in the butt (and improved gas mileage). It made a HUGE performance difference.

However, on a trip, if you were going downhill, so to speak, such as from Arizona downhill to Needles, CA, your car would start some serious pinging. You always had to have that wrench and timing light on a trip.

alanme123

Someone tell me what 99 octane is in China because I know for a fact that they say 99 but its definitely not because they have it at all gas stations there.

C280 Sport

Just did my first fill up on my new to me 20k mile E. I used 93 octane at a Gulf Station on I-90.

Higgs Boson

most other parts of the world use a different rating system than the us, RON and MON. sort of like us still not using the metric system.

no_mulligan

To those that lease and want to use anything less than Premium gas:

Let's day you drive 10K per year and premium is 30 cents more, you *potentially* want to save $120 a year and risk damage to a car. If that is so, do you also pass on the recommended maintenance as well except for a quick oil change? You certainly will save more money there.

I wouldn't do it.

K-A

Not to mention you lose HP and get worse MPG. In the end, it probably balances out. Just get the 91 and get your cars peak performance and MPG.... it probably won't even cost you any extra.

ghstudio

US and Candada posted octane numbers are actually Anti Knock Indexes (AKI) rather than Research Octane Numbers (RON) posted in the rest of the world.

http://en.wikipedia.org/wiki/Octane_rating

RyanRice

You would think a higher Octane (or AKI) would mean it burns faster, right? Wrong, it burns slower. The slower burn allows for a more controlled detonation, burning from a single point vs multiple points (aka detonation or pinging). Just some random trivia.

Also, some gas stations in the US, particularly Sunoco, offer higher than 93, sometimes 101 octane, at their regular stations. Wouldn't make your E class any faster, but it's a nice option if you have a race car or high compression engine around.

K-A

Indeed. Another thing people generally don't seem to know is that if your car isn't optimized for a higher octane (i.e it's designed and recommended to run on 87) then putting a higher octane will actually do more harm than good. The motor can't burn the higher octane, therefore not only getting worse performance, but allowing more build-up to occur, and maybe even get worse MPG.

I learned this in back in the day when I was putting 91 in my Mustang GT to "give it the best". Turned out I was wasting money to do worse for my car. The car even felt peppier with 87.

Thom228

I will be taking delivery of my W212 this week, but I plan on using in it what I have always used in my MINI, which is 93 octane in 100% gas. I am lucky to have several choices for ethanol-free gas in my town and have found an extra 3 or so mpg when I run pure gas.

Do any of you run pure gas and if so, do you notice an improvement in mpg or performance?

rufmb

Premium only from Mobil and Shell here.

R-N

Always, I'ts a Benz treat it right

El Cid

South Carolina has 87, 89 and 93 octane gasoline. I use 93 and always will, even though the price differential is increasing. Used to be 20 cents more than 87, but now is as much as 45 cents more sometimes.
Apparently, it costs more to refine premium, more to ship it via pipelines and distributors charge more to transport it in trucks. Anyway, that's their story.
Using less than 91 lowers your fuel efficiency and your performance.
BTW, can get non-ethanol premium in my area, but very expensive and only from indpendent stations.

MBNUT1

I never get these threads. The differential between regular and premium here is 20 cents. It's been 20 cents whether regular was 2 or 4 bucks a gallon. When the price of regular goes up then people come on line and start asking these questions. It would actually make more sense to cheap out when the price was low as it represents a higher percentage of the fuel cost. Anyway to run regular you are essentially throwing away the advantage in efficiency garnered by the higher compression engine.

I still run premium in my '98 190K A4 1.8T because that is what it was specified to run with.

MBNUT1

I remember those days.....

Nuru

I do too, but now that wrench and the distributor with points, have been replaced by engine computers and flash modules

Seems like one of those Aftermarket modules programmed for multiple types of driving (Sport, Economy, Valet, Factory stock/standard) would do the trick.

MBNUT1

I became religious about keeping my cars in tune after a burnt set of points left us stranded on the side of the turnpike one night. It used to be good fun to tune my dads 250SE because with a fresh tune it would chirp the tires on the shift from first to second.