desmo996

When you pop open the fuel filler door I notice that the minimum required octane is stated as 93 . Unfortunately in Vegas and in CA the maximum octane you can get is 91.

Will using 91 damage the engine over time or is the mileage the only thing that will suffer?

Vegas guys - are there any stations around with higher octane fuel? I think there used to be a 76 on Buffalo that had racing gas (100 octane). Not sure if it still does.

BerBer63

No

Merc63

Timing may be retarded slightly if the engine detects detention. I believe that is how it works...

Merc-Skycap

Well I used to try to put High Octane but gave up after a while. If you need a list of High Octane stations I could post it.

pmknapp

Merc, to your knowledge what would be the "high" octain good for the car and not damage the pistons due to heat of the combustion chamber? I have seen holes poped in the piston when using Trick or other 110 fuels, do not think C63 would have that problem just wanted to ask. I am really looking for 93 octain in my area, but someday will find it. Ever hear of anyone adding octain booster? I do not like nor will use additives but had to ask. Thanks
Drive safe

sjhugh

In Australia the owner’s manual states the use of 98 octane fuel only. It also states lower rated fuel is only to be used as a one off in case of an emergency and if 98 is not available to you on a regular basis, don’t use additives but see your Benz dealer ASAP and have the tune adjust to accept lower rated fuel.

Sincity

Get the PC tune from Evosport. It is tuned for 91.

LOL Vegas Guys. I think there is only 3 active C63 members here on mbworld. You, VegasAMG, and myself.

desmo996

Assuming the cars are all the same regardless of where they are sold I find these different minimum requirements confusing. In Australia they are saying minimum 98 or MB needs to retune engine!? If that's the case then using 91 would seem detrimental to engine and engine performance. I certainly hope thus isn't the case or the states of CA and NV are requiring us to damage our $70K cars....

jturkel

at least your 91 octane is 91 octane.

tests on arizona 91 octane has shown its closer to 87.....i WISH i had real 91, let alone 93

like previously said, timing will be a little retarded and your car wont be as quick, but keep in mind, all the other cars there are running the same stuff too, so it evens out the playing field

desmo996

Your right. So next time I'll refer to Vegas guys as the "C" Musketeers then

BTW, do you know of any stations here that have higher octane or racing gas (to mix in)?

Vegas_AMG

Third Musketeer chiming in.

Rebel use to have 100 oct, haven't checked in a while. When I use to go to the track in my mustang I did a blend mix 50% 100 and 50% 91. But for round-town driving 91 is fine. Other countrys octane rating are differnt than here in the US. In Europe they get the "good stuff" but it is pricey.

sjhugh

Fuel in Australia is expensive and regardless of the manufacturer, most factory stock tuned vehicles can operate between differing octane ratings, though with some effect on performance and consumption. I don’t know how our fuel compares to that used in the USA but I’ve quoted the warning in the manual for my C63 word for word.



C-Class Owner’s Manual

Page 169

Refuelling

AMG vehicles


! Refuel using only unleaded super grade petrol with a minimum octane number of 98 RON/88 MON conforming to European standard EN 228.

Otherwise, you could impair engine output or damage the engine.

(i) If the recommended fuel is not available and only as a temporary measure, you may also use premium unleaded petrol, 95 RON/85 MON. This may reduce engine performance and increase fuel consumption. You must avoid driving at full throttle.

! In emergences, and only when the recommended fuel is not available, you may also use standard unleaded petrol, 91 RON/82.5 MON.

However, using this fuel results in considerably higher petrol consumption and significantly reduced engine output. Avoid driving at full throttle.

If no fuel other than regular petrol 91 RON/82.5 MON or a lower grade is permanently available, you should have the vehicle adapted to run on this fuel by the local after-sales service.


Page 281

Notes on fuel consumption


! Do not use any special additives, as they can cause malfunctions and engine damage. Damage resulting from the use of such additives is not covered by the Mercedes-Benz implied warranty.

desmo996

Is 91 RON the same thing as the 91 octane we are using here in the US? If it is this sounds like a bigger problem than I thought requiring the car to be adapted to the lower rated fuel. It even say no full throttle with 91 octane. Is this for real??? WTF???

sjhugh

RON is unit measurement for the octane rating.

What does RON mean?

Research Octane Number (RON) is a measure of a fuel's compression performance and the RON rating given translates into the amount of engine power. RON requirements vary according to engine type. A knocking noise can occur in an engine when there is a mismatch between the fuel characteristics and the engine's design, particularly its compression ratio, resulting in pre-ignition (also known as 'pinging').
Many imported cars, and particularly those with turbochargers, are manufactured to run on premium unleaded petrol. Selecting fuel with the correct RON for your engine will prevent the knocking fuel effect caused when the fuel combusts in the compression chamber too early.

This link gives a good write-up on octane ratings and their effect on engines:

http://www.themotorreport.com.au/691...octane-number/

Sincity

Wasn't there a 76 that also had 100 octane? LOL @ C Musketeers. Our group will never be as large as the Vancouver group. Seems like a C63 up there is as common as an Accord. I went up there and met a few of them; real cool bunch of guys.

BTW-Beware of a HPF* E46 M3 around Summerlin. My friend with the E90 M3 ran him on Charleston near the 215 and it ate him up.

*HPF=Horsepower Freaks. They make some monsterous turbo kits for the E46 M3.

desmo996

So therefore these cars should be running on 93 octane. I take it 91 won't cause any engine knocking though, right?

Merc63

This is for a car designated to the Australian market. Im sure whichever market they send a car to they take the fuel available into consideration.

Merc-Skycap

Unless you are going to go race, 91 Octane will suffice for the C63. However, I always like to go by what AMG advises so if you do find 93 then use that. Also you don't need 100 Octane or more because it isn't a jet that you are fueling here and mixing octane boosters with 91 is not worth it either. The octane boosters slightly boost your octane level when added properly. Please also keep in mind that frequently using High Octane, above what is recommended, and octane boosting does take a toll on the engine in the long run. I hope that helps!


Enjoy Your Ride In Great Health!

sjhugh

I don’t know what differences there are if any, in the octane rating of fuels between countries. To say they are different when RON is an International Standard, not something peculiar to Australia would be to say, the standard of manufacture is not met in some Countries. I do know in Australia 91, 95 and 98 is readily available. Even 102 was at one stage but due to limited interest the refineries stopped producing it for mass sale at pumping stations.

The fuel filler door on my car states the use of 98 RON and 93 RON as a minimum, which in some ways is a confusing contradiction to the owner’s manual. The manual states, 95 to only be used as a temporary measure and 91 in emergences.

My car is a few days old and is currently stock. All my previous cars have been at a minium tuned. Advice on the fuel type to be used was always giving by the tuner. Simply, 98 was to be used and if nothing else was available use a lower octane and take it easy and fill it with the correctly rated fuel as soon as possible or retune the vehicle.

Internet forums are a great place to get advice, unsubstantiated or not. How do you know which members are correct and which are not? One thing you can be sure of, if something does go wrong, it’s not the forum members who will make the decision on wether your warranty will be honoured or not. Personally I believe 91 to be too low an octane rating for a high performance vehicle.

I know if I was in your position and had doubts about what I should be using as a minium, I would be immediately in contact with the service department of the MB dealer for advice. In fact, to be on the safe side, I would make sure any advice I was given was in writing.

An email to your Service Manager may instantly alleviate all your fears.

MB_Owner

Europe (RON) 95 = USA (PON) 91

And 98 = 93

RON = Research Octane Number
MON = Motor Octane Number
PON = Pump Octane Number...the rating method used in US and is defined as (RON+MON)/2

sjhugh

Thanks MB_Owner, that goes a long way to help clear up some of the confusion.

Swiftler

Thanks for the great info guys!

So then which Multi-National Companies produces better in 91 octane? Shell or ExxonMobile?

MB_Owner

My Porsche dealer service advisor recommended using gas from the Top Tier retailers...he claims the premium additives they use amounts to more than just marketing hype.

OTOH, you might also find this USA Today article an interesting read for alternative opinions.

Swiftler

Great read and their information is accurate. I just went to my MB dealership in Toronto, the manager advised me to use Sunoco and when I'm in USA to do business use Chevron. He says that it is ok to use 91 octane from Shell, but he recommends me to tell his staff next time I bring my S63 to schedule service for cleaning the fuel tank. He mentioned that it gets rid of gunk.

desmo996

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?