Octane question
MBWorld Fanatic!
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02 C32 AMG
Wow so us guys who are stuck having to use 91 octane should schedule regular fuel tank cleanings I guess. That really sucks because that creates am extra service fee that those who can get 93 octane don't have to worry about.
Why don't NV and CA get 93 octane gas in the first place?
Why don't NV and CA get 93 octane gas in the first place?
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Porsche 991S, Cayenne S, 1972 BMW 3.0CS E9 Coupe
fwiw, I normally use Chevron 91 and once in awhile add some Techron.
But there are three 76 stations in my neighborhood (and more a bit farther away) that sell 100% octane. Once in a while I've done a mix of 91 and 100.
No difference in performance that I can really feel, but I do get better gas mileage.
ps, that thing about cleaning the gunk out of the tank from Shell 91 sounds like a dealer's crock of sh*t, sorry.
But there are three 76 stations in my neighborhood (and more a bit farther away) that sell 100% octane. Once in a while I've done a mix of 91 and 100.
No difference in performance that I can really feel, but I do get better gas mileage.
ps, that thing about cleaning the gunk out of the tank from Shell 91 sounds like a dealer's crock of sh*t, sorry.
Senior Member
Joined: May 2009
Posts: 291
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From: Germany
M-B GLE, Porsche 911 Turbo, Porsche Boxster (spouse)
I took a look at the 2010 online Owner's Manual and it makes no differentiation in octane rating requirements for the AMG version...minimum of 91 (PON) for all US spec engines.
"Fuel requirements
Only use premium unleaded gasoline. The
octane number (posted at the pump) must be
91 min. It is an average of both the Research
Octane Number (RON) and the Motor Octane
Number (MON): (RON+MON)/2. This is also
known as the ANTI-KNOCK INDEX.
Reformulated gasolines (RFG) and/or
unleaded gasoline containing oxygenates
such as ethanol, TAME, ETBE, IPA, IBA, and
TBA can be used provided the ratio of any one
of these oxygenates to gasoline does not
exceed 10%; MTBE must not exceed 15%.
The ratio of methanol to gasoline must not
exceed 3% plus additional cosolvents.
Using mixtures of ethanol and methanol is not
allowed. Gasohol, which contains 10%
ethanol and 90% unleaded gasoline, can be
used.
These blends must also meet all other fuel
requirements, such as resistance to spark
knock, boiling range, vapor pressure, etc."
So I'm curious to know why the AMG fuel door sticker would specify 93?
Further, I see SoCal's largest AMG dealer, M-B Long Beach specifies 91.
Lastly, I found nothing in the Owner's Manual mentioning a need to flush the gas tank periodically when using lower-octane gas in emergencies. Looks like unnecessary dealer profit to me.
"Fuel requirements
Only use premium unleaded gasoline. The
octane number (posted at the pump) must be
91 min. It is an average of both the Research
Octane Number (RON) and the Motor Octane
Number (MON): (RON+MON)/2. This is also
known as the ANTI-KNOCK INDEX.
Reformulated gasolines (RFG) and/or
unleaded gasoline containing oxygenates
such as ethanol, TAME, ETBE, IPA, IBA, and
TBA can be used provided the ratio of any one
of these oxygenates to gasoline does not
exceed 10%; MTBE must not exceed 15%.
The ratio of methanol to gasoline must not
exceed 3% plus additional cosolvents.
Using mixtures of ethanol and methanol is not
allowed. Gasohol, which contains 10%
ethanol and 90% unleaded gasoline, can be
used.
These blends must also meet all other fuel
requirements, such as resistance to spark
knock, boiling range, vapor pressure, etc."
So I'm curious to know why the AMG fuel door sticker would specify 93?
Further, I see SoCal's largest AMG dealer, M-B Long Beach specifies 91.
Lastly, I found nothing in the Owner's Manual mentioning a need to flush the gas tank periodically when using lower-octane gas in emergencies. Looks like unnecessary dealer profit to me.
MBWorld Fanatic!
Joined: Dec 2006
Posts: 4,949
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From: Clifton, NJ
96 and 08 911 turbos
Running higher octane than your car is tuned for is simply a waste of money. Unless you are running leaded fuel (typically above 104) will greatly reduce the life of your 02 sensors and cats. In addition, high octane race fuel has a different stoich a/f than typical pump gas.
Running 100 octane on a stock C63 will not damage the engine, but its a waste of money and will most likely cause the car to generate LESS power.
Thread Starter
Member
Joined: Jul 2009
Posts: 143
Likes: 0
From: Las Vegas
BMW 335i, Ducati 996, Mercedes C63 AMG
I took a look at the 2010 online Owner's Manual and it makes no differentiation in octane rating requirements for the AMG version...minimum of 91 (PON) for all US spec engines.
"Fuel requirements
Only use premium unleaded gasoline. The
octane number (posted at the pump) must be
91 min. It is an average of both the Research
Octane Number (RON) and the Motor Octane
Number (MON): (RON+MON)/2. This is also
known as the ANTI-KNOCK INDEX.
Reformulated gasolines (RFG) and/or
unleaded gasoline containing oxygenates
such as ethanol, TAME, ETBE, IPA, IBA, and
TBA can be used provided the ratio of any one
of these oxygenates to gasoline does not
exceed 10%; MTBE must not exceed 15%.
The ratio of methanol to gasoline must not
exceed 3% plus additional cosolvents.
Using mixtures of ethanol and methanol is not
allowed. Gasohol, which contains 10%
ethanol and 90% unleaded gasoline, can be
used.
These blends must also meet all other fuel
requirements, such as resistance to spark
knock, boiling range, vapor pressure, etc."
So I'm curious to know why the AMG fuel door sticker would specify 93?
Further, I see SoCal's largest AMG dealer, M-B Long Beach specifies 91.
Lastly, I found nothing in the Owner's Manual mentioning a need to flush the gas tank periodically when using lower-octane gas in emergencies. Looks like unnecessary dealer profit to me.
"Fuel requirements
Only use premium unleaded gasoline. The
octane number (posted at the pump) must be
91 min. It is an average of both the Research
Octane Number (RON) and the Motor Octane
Number (MON): (RON+MON)/2. This is also
known as the ANTI-KNOCK INDEX.
Reformulated gasolines (RFG) and/or
unleaded gasoline containing oxygenates
such as ethanol, TAME, ETBE, IPA, IBA, and
TBA can be used provided the ratio of any one
of these oxygenates to gasoline does not
exceed 10%; MTBE must not exceed 15%.
The ratio of methanol to gasoline must not
exceed 3% plus additional cosolvents.
Using mixtures of ethanol and methanol is not
allowed. Gasohol, which contains 10%
ethanol and 90% unleaded gasoline, can be
used.
These blends must also meet all other fuel
requirements, such as resistance to spark
knock, boiling range, vapor pressure, etc."
So I'm curious to know why the AMG fuel door sticker would specify 93?
Further, I see SoCal's largest AMG dealer, M-B Long Beach specifies 91.
Lastly, I found nothing in the Owner's Manual mentioning a need to flush the gas tank periodically when using lower-octane gas in emergencies. Looks like unnecessary dealer profit to me.
Great research!
Then the mystery is ultimately why the owners manual contradicts what the sticker on the fuel door says. Which one is accurate for this car, a minimum octane of 91 or 93? The owner's manual explanation does seem more in depth.
Last edited by desmo996; Aug 23, 2009 at 12:57 PM.
Member
Joined: Jun 2010
Posts: 77
Likes: 0
From: St. Albert, AB
2011 C63 P31
Necropost!
I'm in Alberta, Canada and it's very hard to come by anything higher than 91 octane. Certain gas stations have 94 octane, but it contains (I believe) "up to 10% ethanol".
Gas nerds - would it be better to go with the blended 94 or the 91? Typically, I run Shell V-Power 91 (but I've only filled up my UberBeast once so far)...
I'm in Alberta, Canada and it's very hard to come by anything higher than 91 octane. Certain gas stations have 94 octane, but it contains (I believe) "up to 10% ethanol".
Gas nerds - would it be better to go with the blended 94 or the 91? Typically, I run Shell V-Power 91 (but I've only filled up my UberBeast once so far)...
MBWorld Fanatic!
Joined: May 2005
Posts: 2,825
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From: New Jersey
things with and without wheels
if you use low octane fuel instead of what the manufacturer call for,it will lead to serious engine problems down the road.
Preignition is going to damage the pistons, engine computer will retard the timing but not enough.
Low octane fuel burns faster then high octane, when the cylinder is coming up on it's power stroke, fuel is introduced and it ignites too fast causing the piston to rattle in it's bore(piston is still traveling upwards while the combustion is trying to push it down) as well as damaging the piston ring lands.
low octane fuel gives you less bang for your dollar as well ,by causing you to press the throttle little more to achieve the same performance using high octane fuel.
Preignition is going to damage the pistons, engine computer will retard the timing but not enough.
Low octane fuel burns faster then high octane, when the cylinder is coming up on it's power stroke, fuel is introduced and it ignites too fast causing the piston to rattle in it's bore(piston is still traveling upwards while the combustion is trying to push it down) as well as damaging the piston ring lands.
low octane fuel gives you less bang for your dollar as well ,by causing you to press the throttle little more to achieve the same performance using high octane fuel.
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Joined: Feb 2010
Posts: 5,649
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2012 C63;1971 280SE 3.5(Sold);2023 EQS 450 SUV 4 Matic (Wife's)
Necropost!
I'm in Alberta, Canada and it's very hard to come by anything higher than 91 octane. Certain gas stations have 94 octane, but it contains (I believe) "up to 10% ethanol".
Gas nerds - would it be better to go with the blended 94 or the 91? Typically, I run Shell V-Power 91 (but I've only filled up my UberBeast once so far)...
I'm in Alberta, Canada and it's very hard to come by anything higher than 91 octane. Certain gas stations have 94 octane, but it contains (I believe) "up to 10% ethanol".
Gas nerds - would it be better to go with the blended 94 or the 91? Typically, I run Shell V-Power 91 (but I've only filled up my UberBeast once so far)...
The 93 min. on the fuel door is for RON rating only and it is a higher rating used in Europe and other places but not in North America.
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From: Maryland
2011 GLK350, 2010 ML350, 2008 C63 AMG
So in Maryland, Sunoco has 93 and 91 and I put 93 in the C63 but for my other cars like the ML and GLK which need premium gas, should I just put in 91 instead of 93?
Member
Joined: Jun 2010
Posts: 77
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From: St. Albert, AB
2011 C63 P31
In Canada the octane rating is an average of RON/MON and 91 Octane is the minimum posted octane rating for Premium unleaded gasoline as required by MB. Shell V-Power 91 is acceptable for use in the C63 and is good quality gasoline.
The 93 min. on the fuel door is for RON rating only and it is a higher rating used in Europe and other places but not in North America.
The 93 min. on the fuel door is for RON rating only and it is a higher rating used in Europe and other places but not in North America.
Member
Joined: May 2009
Posts: 233
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From: Shanghai & Toronto
2015 Porsche C2S, 2014 ML63 AMG, & 2012 Maserati Quattroporte S
In Canada the octane rating is an average of RON/MON and 91 Octane is the minimum posted octane rating for Premium unleaded gasoline as required by MB. Shell V-Power 91 is acceptable for use in the C63 and is good quality gasoline.
The 93 min. on the fuel door is for RON rating only and it is a higher rating used in Europe and other places but not in North America.
The 93 min. on the fuel door is for RON rating only and it is a higher rating used in Europe and other places but not in North America.
MBWorld Fanatic!
Joined: Feb 2010
Posts: 5,649
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2012 C63;1971 280SE 3.5(Sold);2023 EQS 450 SUV 4 Matic (Wife's)
I run Shell when I can because I think it has a better additive package than other local New Brunswick stations and try to buy from higher volume stations and hope the gas is fresher with less chance of contaminants and water in the tank.
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2012 C63;1971 280SE 3.5(Sold);2023 EQS 450 SUV 4 Matic (Wife's)
We do not have Petro Canada Ultra 94 here AFAIK so I am not sure. We don't even have a convenient Petro Can station so I never use or consider it. If you try the Ultra 94 and do not notice any difference then I would save the dollars (if any) and use the Shell V-Power 91 for DD. I don't know much about the quality of Petro Canada gas but up to 10% ethanol can be used. I am not sure I would use it if I had other options.
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From: W Coast & E Europe
08 E63, 07 RS4, 04 GT3, 10 LR4, 02 Pajero
Wow so us guys who are stuck having to use 91 octane should schedule regular fuel tank cleanings I guess. That really sucks because that creates am extra service fee that those who can get 93 octane don't have to worry about.
Why don't NV and CA get 93 octane gas in the first place?
Why don't NV and CA get 93 octane gas in the first place?
I'm just glad someone posted about the differing fuel ratings between the US/EUR/AUS. This must be one of the most discussed auto subjects on the internet and all the information is already out there.
