91 Octane Gas V12
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2007 S600
Bottom line: use 91 octane , at least in a V12 and especially if you plan to keep the car for an extended period of time.
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From: East Bay Area, CA
2013 SL 550 (Previously 2012 Porsche Panamera Turbo-S, 2015 Tesla P85D, 2007 S600, 2005 E55 AMG)
I notice that the sticker on the inside of the fuel flap on my car says use 93 Octane only! (Which of course is hard to find in your average CA gas station. I assume that must be a Euro Octane rating that has not been Americanized)
Chris
Chris
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From: CA
2010 CL65
Suspect US 93 oct is ideal vs any perf engine....93 oct is easily available in most ex-CA locales like NYC....clearly, CA is world's biggest mkt for $150K+ perf cars....so mfrs coordinate ECU's to compromise vs CA's 91 oct....
One can abuse a $150K+ car w/various approaches like using cheapest avail fuel; avoiding/delaying rec'd mtce; delaying replacement of worn tires....and putting on cheapest avail non-perf tires, etc etc....but laughably self-defeating frugality when driving a fast-depreciating $150K+ car.....
One can abuse a $150K+ car w/various approaches like using cheapest avail fuel; avoiding/delaying rec'd mtce; delaying replacement of worn tires....and putting on cheapest avail non-perf tires, etc etc....but laughably self-defeating frugality when driving a fast-depreciating $150K+ car.....
Thread Starter
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Joined: Jun 2007
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From: Los Angeles
2010 S600 sold
You're probably not going to be aware of a difference but your engine will in the long run. I have always ran 89 octane in every car I've owned UNTIL I bought my 2007 S600. The reason I changed my mind and started using 91 is because I read where the valves and pistons develop a lot of carbon buildup using the cheaper fuels and this will cost you plenty down the road. Also because I have the Renntech upgrade and it was programmed with the assumption I will use 91 octane. It will also not perform as well because the onboard diagnostics (ECU) will make adjustments to the timing that may screw the performance up a bit.
Bottom line: use 91 octane , at least in a V12 and especially if you plan to keep the car for an extended period of time.
Bottom line: use 91 octane , at least in a V12 and especially if you plan to keep the car for an extended period of time.
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From: East Bay Area, CA
2013 SL 550 (Previously 2012 Porsche Panamera Turbo-S, 2015 Tesla P85D, 2007 S600, 2005 E55 AMG)
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S Class, XC90 and Auris
.
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From: CA
2010 CL65
In an ideal world, wish CA would have easily avail 95 oct fuel, smoothly paved roads and no speed lims on fwys....
But we do have world's cheapest cars and some of world's best weather/topography/mtn twisties around SF and LA to enjoy our cars 365d/yr on summ perf tires/wheels
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Commuter:CRG 125 Shifter Cart/Honda VTR 1000 RC 51/Pacer with 15" wheels, "But I keep them clean."
More then likely you will have the same problem I had when my wife accidentally put 89 in our clk 55. The computer will try to adjust timing for the lower octane but may not be totally successful. You will more then likely get some knocking, loss of power, and some abnormally slow starts. I remember gettiing in our car trying to start the car and it sitting there trying to struggle until it finally started. I recommend you don't try it. This was what I wanted to do to my wife.
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Joined: May 2007
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2007 S600
BTW, Does running 98 octane do harm as much as running low octanes do? If it says run 93 octance on the sticker, can that be interpreted as 93 or higher?
Last edited by trumpet1; Feb 7, 2008 at 08:46 PM.
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From: San Diego, CA
2004 E55 AMG
Octane is made up of 3 different numbers:
RON: Research Octane Number.
MON: Motor Octane Number.
AKI: Anti-Knock Index. ((RON+MON)/2)
European fuels are measured by RON (ie. "98 RON")
American fuels are measured by AKI (ie "93 octane")
Typical difference in RON:MON is approx. 10 points (although it varies with different brands, qualities), so 98RON/88MON = (98+88)/2 = 93 AKI, so it's the same rating.
My opinion on lower octane gases: the difference between 89 and 91 is 10 cents? 20 cents at most? So say you have a 20 gallon tank @ $3/gallon, you'd be paying a whopping $64 for 91 instead of $60 for 89. IMO the damage that could potentially be done to your engine isn't worth saving that $4 for. On that note, I also only fill up at quality gas stations (chevron, 76, shell) again because I wouldn't want to risk putting in gas with unknown quality to save a couple of bucks in the short run.
On a side note, lower "octane" gas is actually better, because the word "octane" is a misnomer - 87,89,91,93 are anti-knock indexes - 91 is more resistant to burning than 87 and thus the reason for it being less sensitive to detonation.
If your car calls for 87 gas, use 87 gas because 91 will negatively impact performance.
RON: Research Octane Number.
MON: Motor Octane Number.
AKI: Anti-Knock Index. ((RON+MON)/2)
European fuels are measured by RON (ie. "98 RON")
American fuels are measured by AKI (ie "93 octane")
Typical difference in RON:MON is approx. 10 points (although it varies with different brands, qualities), so 98RON/88MON = (98+88)/2 = 93 AKI, so it's the same rating.
My opinion on lower octane gases: the difference between 89 and 91 is 10 cents? 20 cents at most? So say you have a 20 gallon tank @ $3/gallon, you'd be paying a whopping $64 for 91 instead of $60 for 89. IMO the damage that could potentially be done to your engine isn't worth saving that $4 for. On that note, I also only fill up at quality gas stations (chevron, 76, shell) again because I wouldn't want to risk putting in gas with unknown quality to save a couple of bucks in the short run.
On a side note, lower "octane" gas is actually better, because the word "octane" is a misnomer - 87,89,91,93 are anti-knock indexes - 91 is more resistant to burning than 87 and thus the reason for it being less sensitive to detonation.
If your car calls for 87 gas, use 87 gas because 91 will negatively impact performance.
MBWorld Fanatic!
Joined: May 2007
Posts: 2,071
Likes: 2
2007 S600
Octane is made up of 3 different numbers:
RON: Research Octane Number.
MON: Motor Octane Number.
AKI: Anti-Knock Index. ((RON+MON)/2)
European fuels are measured by RON (ie. "98 RON")
American fuels are measured by AKI (ie "93 octane")
Typical difference in RON:MON is approx. 10 points (although it varies with different brands, qualities), so 98RON/88MON = (98+88)/2 = 93 AKI, so it's the same rating.
My opinion on lower octane gases: the difference between 89 and 91 is 10 cents? 20 cents at most? So say you have a 20 gallon tank @ $3/gallon, you'd be paying a whopping $64 for 91 instead of $60 for 89. IMO the damage that could potentially be done to your engine isn't worth saving that $4 for. On that note, I also only fill up at quality gas stations (chevron, 76, shell) again because I wouldn't want to risk putting in gas with unknown quality to save a couple of bucks in the short run.
On a side note, lower "octane" gas is actually better, because the word "octane" is a misnomer - 87,89,91,93 are anti-knock indexes - 91 is more resistant to burning than 87 and thus the reason for it being less sensitive to detonation.
If your car calls for 87 gas, use 87 gas because 91 will negatively impact performance.
RON: Research Octane Number.
MON: Motor Octane Number.
AKI: Anti-Knock Index. ((RON+MON)/2)
European fuels are measured by RON (ie. "98 RON")
American fuels are measured by AKI (ie "93 octane")
Typical difference in RON:MON is approx. 10 points (although it varies with different brands, qualities), so 98RON/88MON = (98+88)/2 = 93 AKI, so it's the same rating.
My opinion on lower octane gases: the difference between 89 and 91 is 10 cents? 20 cents at most? So say you have a 20 gallon tank @ $3/gallon, you'd be paying a whopping $64 for 91 instead of $60 for 89. IMO the damage that could potentially be done to your engine isn't worth saving that $4 for. On that note, I also only fill up at quality gas stations (chevron, 76, shell) again because I wouldn't want to risk putting in gas with unknown quality to save a couple of bucks in the short run.
On a side note, lower "octane" gas is actually better, because the word "octane" is a misnomer - 87,89,91,93 are anti-knock indexes - 91 is more resistant to burning than 87 and thus the reason for it being less sensitive to detonation.
If your car calls for 87 gas, use 87 gas because 91 will negatively impact performance.
Wow. Great information. Thanks for the knowledge. I used to know that part about RON,MON, and AKI but over the years forgot it. Nice refresh of info.
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1953 Fiat Topolino
Use Top Tier Detergent Gasoline only...
Re: I totally agree with Trumpet1s comment: "I also only fill up at quality gas stations (chevron, 76, shell) again because I wouldn't want to risk putting in gas with unknown quality to save a couple of bucks in the short run." On that note, the following is a quote I found in a website on the this subject matter which might be of interest to others reading this thread: "Some manufacturers say that today's high-tech engines require higher-standard gasoline than the EPA benchmark. Audi, BMW, General Motors, Honda, Toyota and Volkswagen have worked with major gasoline companies to set a standard for what is known as Top Tier Detergent Gasoline. Gas companies that meet these standards include QuikTrip, Chevron, ConocoPhillips, Shell, MFA Oil Company, Kwik Trip/Kwik Star, The Somerset Refinery Inc., Aloha Petroleum, Tri-Par Oil Co., Texaco, Petro-Canada and Sunoco-Canada." I also found this link for more info on "Top Tier Detergent Gasoline".
http://autorepair.about.com/od/generalinfo/a/110305.htm
Z356
http://autorepair.about.com/od/generalinfo/a/110305.htm
Z356
