Can I safely use < 91 octane in my 2014 E350?
#2
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Knock sensors will adjust to the lower octane, but just don't expect to get the full performance from the engine (horsepower and fuel economy). Not worth it IMO.
Last edited by dchar; 06-18-2017 at 12:44 PM.
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2014 E550-sold 😩
Why?
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tresean1 (06-19-2017)
#4
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My 2010 E550 knocks like crazy when idling when there's 87 in it. (I watched a YouTube video explaining that it is all the same. Don't believe everything you see), I just buy 91 now, and its very smooth, with the occasion micro jutter once in a while, but overall alot more smoother than when I put 87 in. Performance and fuel economy wise, didn't notice a difference.
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1922 Ford Model T / no OBD
You can also save money by skipping M1 and fill up the crankcase with cooking oil.
They sell it very cheap in convenient jugs at Costco.
They sell it very cheap in convenient jugs at Costco.
#7
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Expect a 10% loss in performance, put in the tank what is recommended. There is a reason for that. Some newer turbo cars maintain you can use a lower octane without mechanical issues but performance issues will exist (eco boost motors for example). You own a Mercedes don't skimp on gas.
Last edited by PLINYELDER; 06-18-2017 at 08:45 PM.
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tresean1 (06-19-2017)
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2014 ML350 2w, 2017 GLS550, 1967 Pontiac GTO 4 sp
Your car has a 12:1 compression ration. My '67 GTO is 10.75:1. If I tried to run 89 or less in it, the engine would sound like there were ball bearings rattling around in the cylinders. My wife's '14 ML350 is also 12:1. Might be the same engine as yours (same hp). Inside of fuel door says 91 or more. We don't get 91 here, just 89 and 93. So your heading asks if you can run 91. If you can get it and your fuel door says 91 or more, you're good. Like another poster said, the engine will adjust the timing to avoid the knock you cannot hear to protect the engine. But you will not be getting all the power the engine was designed to deliver.
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raja777m (06-19-2017)
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2014 E550-sold 😩
#19
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How much are you really saving by doing this? Say 89 octane is 15 cents cheaper a gallon than 93 and you fill up 3 times a month on average and 36 times a year. Half of the fill up in which you use 89 you will save $2.70, that comes out to $48 a year. Hardly worth the time or the effort.
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KEY08 (06-20-2017)
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2014 E550-sold 😩
^ bingo!
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2014 E350 4M Diamond Silver
Before getting into luxury, I told myself many times, "Premium gas, Higher maintenance costs, Don't expect reliability if I r*pe the crap out of it".
I don't even wanted to take it to Costco to save those 20cents per gallon.
I promised myself, Shell, Exxon, Mobil1 or BP; premium only, else, I won't buy the car for myself
So, I joined fuel rewards network from Shell, and Plenti from Exxon/Mobil1(if in case) for some perks and cash back.
I don't even wanted to take it to Costco to save those 20cents per gallon.
I promised myself, Shell, Exxon, Mobil1 or BP; premium only, else, I won't buy the car for myself
So, I joined fuel rewards network from Shell, and Plenti from Exxon/Mobil1(if in case) for some perks and cash back.
#22
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First question. . . WHY? If the MB engines run anything like my 4.3L V8 Lexus did you will save about. . . NOTHING. There were user tests run with the Lexus LS430 using both regular and premium fuels. While the regular was cheaper per gallon, users found that the engine management systems de-tuned their engines (although imperceptibly) to use the lower octane, WHICH RESULTED IN LOWER GAS MILEAGE. The lower mileage just about offset the reduced cost per gallon, resulting in almost identical cost per MILE with either fuel.
BTW, faja, if you read the Costco Pledge, they pledge to distribute only Top Tier gasoline, which is technically equal to any of the brands you mentioned. I've been using Costco gas in two MB's over the past few years and it is fine.
BTW, faja, if you read the Costco Pledge, they pledge to distribute only Top Tier gasoline, which is technically equal to any of the brands you mentioned. I've been using Costco gas in two MB's over the past few years and it is fine.
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2014 E350 4M Diamond Silver
First question. . . WHY? If the MB engines run anything like my 4.3L V8 Lexus did you will save about. . . NOTHING. There were user tests run with the Lexus LS430 using both regular and premium fuels. While the regular was cheaper per gallon, users found that the engine management systems de-tuned their engines (although imperceptibly) to use the lower octane, WHICH RESULTED IN LOWER GAS MILEAGE. The lower mileage just about offset the reduced cost per gallon, resulting in almost identical cost per MILE with either fuel.
BTW, Raja, if you read the Costco Pledge, they pledge to distribute only Top Tier gasoline, which is technically equal to any of the brands you mentioned. I've been using Costco gas in two MB's over the past few years and it is fine.
BTW, Raja, if you read the Costco Pledge, they pledge to distribute only Top Tier gasoline, which is technically equal to any of the brands you mentioned. I've been using Costco gas in two MB's over the past few years and it is fine.
How much will it cost to run such tests, since, it is worth it, if it is less price, I'm ready to invest on it.
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