Does Everyone put 91+ octane in your E Class?
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Junior Member
Joined: Feb 2013
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2013 E350
Does Everyone put 91+ octane in your E Class?
Jeez. Gas down here is 4.50/gallon for 93. We don't really even have 91. Does everyone put 93 in, or is lower ok? I'm leasing, I don't own it, so as long as it doesn't drastically reduce performance or hurt the engine I'd like to put lower grade in. $80 to fill the tank today on 93.
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2010 E350 Luxury 4Matic
Not only do I put the recommended 91+ at 93, I even put in premium for whatever C-class loaners I've used also, and I wasn't close to owning the loaner of course.
Why take the risk to save a few bucks, for what maybe $100-150/yr? Even in a lease, you are responsible for properly maintaining the vehicle.
Why take the risk to save a few bucks, for what maybe $100-150/yr? Even in a lease, you are responsible for properly maintaining the vehicle.
Thread Starter
Junior Member
Joined: Feb 2013
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2013 E350
Good point. However it's really about $500/year or $50/month for me. I wouldn't do it if its truly harmful to the engine, there has just been talk out there that there isn't aterrinlemdanger out there with 89 octane. Although this could be very untrue.
Senior Member
Joined: Apr 2012
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From: Southern California, Orange County
2012 E350
There was a thread somewhere here that people said they were putting in 87 and it was totally fine. However recommended is at least 91 octane. Do a search on here and you should find it.
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From: Connecticut
2018 BMW 540d
I've owned two Infinities ('03 & '08),both of which featured Nissan's 3.5 litre V6.Both cars *recommended* 91 octane but specifically said that 87 could be used with reduced performance but no damage to the vehicle.Unless I'm mistaken Mercedes *requires* 91 for all its vehicles sold in North America and warns of damage if anything less is used.I don't have a dog in this fight but,particularly when the car's under warranty,why take a chance?
Senior Member
Joined: Apr 2012
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From: Southern California, Orange County
2012 E350
I personally do not know why people put in 87 octane for a car of this price. My thoughts are if someone can afford this car, they would not mind having to pay only a few hundred more per year for gas. But again, thats my opinion. People can do whatever they choose to with their car. 
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2010 E550
I imagine Mercedes has some type of knock sensing system in place to determine when there is detonation (usually caused by lower quality fuels) in the engine, and can reduce ignition timing to prevent damage. In fact I can't see a way around having something like that in place because not all 91/93 octanes are made the same and you can't build a spark/ignition map based on one brand of fuel.
That said, I would recommend the 91+ as that is what their engine calibrators used in building the programming for the engine. Anything less is a potential risk. Will anything bad happen? Probably not, but in the event it did, they could certainly test the fuel quality and deny warranty based on that. 500/year isn't a bad price to pay to ensure that isn't your fault. Also there will be a performance hit, whether or not you can measure it depends on how hard you push the engine, how much it adjusts its timing based on the fuel, and how accustomed you are to minute differences in power.
That said, I would recommend the 91+ as that is what their engine calibrators used in building the programming for the engine. Anything less is a potential risk. Will anything bad happen? Probably not, but in the event it did, they could certainly test the fuel quality and deny warranty based on that. 500/year isn't a bad price to pay to ensure that isn't your fault. Also there will be a performance hit, whether or not you can measure it depends on how hard you push the engine, how much it adjusts its timing based on the fuel, and how accustomed you are to minute differences in power.
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Joined: Jul 2012
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From: HESPERIA CA
2011 E550
I was implying that I did not know there was a 93 octane since there is only 91 in the United states.............. I say WTF MATE all the time, I did not mean it in a racist sarcatic way.................. EDIT there is a 93 in the states, but I haven't seen it :/ so my mistake. but again I was not calling Op out or being sarcatic or anything.
Last edited by bob2011; Mar 5, 2013 at 09:43 AM.
Super Member
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From: HESPERIA CA
2011 E550
Thread Starter
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Joined: Feb 2013
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2013 E350
I'm really sorry. Baby was up all night so I may not be seeing things clearly. I was thinking that perhaps There wasn't a 93 and I mistakenly said it instead of 91. Ugh. Didn't think you we're being racist. Forget I said anything! 
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Joined: Oct 2010
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From: Minnesota
S212 2011 Wagon and Wife's 2014 C350 sedan.
91 Octane Without Ethanol
Here in Minnesota they offer three grades of fuel with Ethanol, 87,89,92.
However, because of the boating, snowmobiling, motorcycle and off road vehicles a few stations have Non-oxygenated 91 premium fuel. That is the best thing I can get for all my vehicles. I get about 10% better milage and the shelf/tank life is much longer.
The ethanol percentage currently is 10% but the corn/farmer lobby petitioned to have the gov. vote in 15% once it is available. To me that is like putting corn syrup in your tank.
The good news is The Minnesota Street Rod Association (MSRA) publishes a list, by city/town where the Non-oxy fuel is available. They do not want the crap ethanol in their prized hot rods.
However, because of the boating, snowmobiling, motorcycle and off road vehicles a few stations have Non-oxygenated 91 premium fuel. That is the best thing I can get for all my vehicles. I get about 10% better milage and the shelf/tank life is much longer.
The ethanol percentage currently is 10% but the corn/farmer lobby petitioned to have the gov. vote in 15% once it is available. To me that is like putting corn syrup in your tank.
The good news is The Minnesota Street Rod Association (MSRA) publishes a list, by city/town where the Non-oxy fuel is available. They do not want the crap ethanol in their prized hot rods.
