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2003 ML55 AMG - 2005 E55 AMG
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Discussion Starter #1
Hi,

I just bought a 03 ML55

I am currently using Premium gas, but was wondering what the best fuel would be to use? Could I use Shell V-Power or should I only use mid-octane fuel? Or just stick with Premium?

I wasn't able to find any other posts about this.

Thanks
 

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'02 ML500 (Kleeman headers, tune, AMG ML55 wheels,3.09 diffs, 3rd row seats);
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Hi,

I just bought a 03 ML55

I am currently using Premium gas, but was wondering what the best fuel would be to use? Could I use Shell V-Power or should I only use mid-octane fuel? Or just stick with Premium?

I wasn't able to find any other posts about this.

Thanks
Although normally aspirated and it will run on regular, given the high compression ratio (either 10 or 10.5:1 from memory), I would stick with premium, 93 octane if available. I am less concerned about brand then octane, but a can of techron every 3rd or 4th tank doesn't hurt.

My ML500 can use either, and no noticable difference in general driving, although I do use premium for towing.

Regards,
Jerry
 

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05 500
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6,512 Posts
Hi,

I just bought a 03 ML55

I am currently using Premium gas, but was wondering what the best fuel would be to use? Could I use Shell V-Power or should I only use mid-octane fuel? Or just stick with Premium?

I wasn't able to find any other posts about this.

Thanks
Premium is the recommended - period. Yeah it will run on mid and even regular (and some do that) but the long term effects could be quite expensive. Several years ago on this forum, we discussed the pro/cons on this same subject. I believe the largest con was that in time, due to knocking, you may stress the motor to premature failure. Run a search on the subject.
 

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2003 ML55 AMG - 2005 E55 AMG
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Discussion Starter #4
Thanks for the input.

I assume, but would like confirmation that V-Power from Shell would be great/good???

I have heard from people that cleaning power in that gas would help on carbon deposits/buildup?

K
 

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02 ML 55 (SOLD: 98 & 02 ML320)
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yeah i remember that long thread...i use premium at all times unless i go on long highway trips where im going to be driving at very low rpms continuously...i might use mid grade.
 

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2000 ML430 (Sold)
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Mine was run on low grade from 2001 to 2010( previous owner) and i believe its a cause in the knocking sound my engine makes. Since i purchased it, it has only ever seen Shell V-Power Premium.
 

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2009 ML320 Bluetec, 2013 Tesla Model S 85
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I assume, but would like confirmation that V-Power from Shell would be great/good???
No. It makes almost no difference at all as to what brand of gasoline you purchase. On average gasoline is sold and resold 7 times between refiner and the final sale. Odds are the gasoline you purchase at Shell was not produced in a Shell refinery.

In any given locale almost all gasoline comes out of the same pipe. However each station/distributor has some say as to just what they get out of the pipe.

Mandatory cleaning additives have not yet been added to the gasoline in the pipeline. Nor has ethanol. They don't want gasoline scouring the crud out of the pipeline which is doing no harm staying right where it is. Also the additives and ethanol content are up to the individual station and/or distributor so those get mixed when fuel is loaded on the delivery truck.

Shell does have a good additive package. But then again everybody seems to have excellent additive packages, Shell just spends more money tooting their own horn than others knowing full well this is the only parameter they can honestly differentiate their fuels from others.

Has been at least 25 years since most gasolines lacked sufficient properties to keep valves and injectors clean. This is one of the few things the EPA properly polices. If fuels don't keep engines clean and healthy then they fall out of tune and pollute, making the EPA unhappy. Also makes automakers unhappy because they have to honor an 8 year 100,000 mile emissions warranty. They have to design for those conditions and for the fuel which is sold. If the fuel is deficient then they'll go pound tables at the EPA.

I say keep a logbook of your fuel purchases. Its rare that a fuel is bad enough for the engine to run rough enough to notice, but not so rare as to affect MPG. Many think watching MPG is beneath their dignity but its a valuable tool for monitoring fuel quality and engine health. But to be valuable you have to have a past history of MPG performance to know when current results are deviating.

Generally it takes 5 tanks in a row to make a statement about a particular fuel source mostly because you don't fill the tank exactly the same every time no matter how hard you try, no matter how skilled you are.

Years ago I would get 24 MPG on most local brands but 22 from the local Exxon. 30+ on interstate but only 26 on this Exxon. Has been a long time since I have purchased Exxon locally as a result. Kangaroo, an independent brand, used to run as well as Shell or any other but a couple of years ago it too turned sour. A Chevron station a mile or so from my house sells as cheap as any. I buy most of my gasoline from them or Sam's Club, depending on where I am when the mood hits.

You should experiment with ethanol-free gasoline if its available in your area. A good locator tool is at http://pure-gas.org/

As for diesel, Krogers has reliably produced as good or better MPG than any I have tried. And Murphy (Walmart) the worst. But again, Your Mileage May Vary. It doesn't matter what others tell you, all that matters is what works for you.
 

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2003 ML55 AMG - 2005 E55 AMG
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Discussion Starter #8 (Edited)
Thanks for taking the time to provide good insight.

I know that some stations are better than others. Own a rav4, and one station makes my check engine module to go off, but once i figured out to buy from a different place it went away and has stayed away ever since. It triggered the emission monitor.

Will just buy premium, and hope they honor the octane rating they give.

Unfortunately no ethanol free stations close to me.
 

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2009 ML320 Bluetec, 2013 Tesla Model S 85
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Will just buy premium, and hope they honor the octane rating they give.
I know your car specifies premium but that too is a parameter I would experiment with. Don't experiment towing until you have exonerated it under less demanding conditions. And remember if you have 91 in the tank and at half tank fill with 89 then the result is 90.

Desperate I once cut 93 with 87 at 50:50 for my Husaberg dirtbike. Figure the result was about 90. It didn't like it although in the past I knew 91 worked just as well as 93. But it was a "had to" situation so that day I had to learn how to avoid the high load conditions it didn't like. Its a relatively simple dirtbike without knock sensor.

Don't worry about knock. There is a knock sensor which is much more sensitive than your ears. Back when I had access to SAE papers GM published an article on knock sensors that was quite enlightening. Initially they were studying just how much knock was safe before engine damage occurred. Then they noticed there was a level of knock below damage and below what humans could hear that efficiency was up and emissions were down.

Using knock sensors (everybody does) Toyota routinely advises 87 octane on 10.5:1 engines.
 

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2002 BMW M3 Coupe, 2002 Mercedes Benz ML320
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My 2002 ML320 calls for "premium fuel" in the fuel filler door but there is no reference to the octane. In the owner's manual, it says the minimum octane is 91 and it also says the maximum percentage of ethanol is 10%.

I try to comply with these recommendations for my vehicle and it bothers me that the EPA now allows up to 15% of ethanol to be put in gasoline. In my opinion, this was done only because of the strength of ethanol lobbyists, not because there are any benefits, economic or otherwise, to using ethanol or other oxygenates. In fact, I think the case has been clearly made that ethanol is detrimental in many ways. Higher grades of fuel tend to have less ethanol and more additives, such as techron, in the case of chevron, which I believe has been proven to be beneficial.

I prefer chevron fuel because chevron worked with BMW to develop techron. BMW's own fuel system cleaner is techron.
 

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87' 190E 16V / 93' 600SL / 02' G500
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Stick with premium you didn't just buy a Hyunday or however you spell it. Running anything else will reduce power and conversely fuel economy will suffer.
 

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Stick with premium you didn't just buy a Hyunday or however you spell it.
:(

What the O.P. did was demonstrate wisdom and frugality in is purchase of a high quality nearly 10 year old car. Then continues on that path of independent thought by asking about the real world fuel requirement rather than be frightened into throwing money at something he might not need.

Running anything else will reduce power and conversely fuel economy will suffer.
Thats a very unconvincing unsupported statement.

High octane gasoline does not have any more energy content than regular. There are special racing fuels which are gasoline compatible with more energy content, but not the stuff at the corner gas station.

Higher compression ratios are able to thermally extract more energy from combustion but usually requires a higher octane-rated fuel. The problem isn't the compression ratio but the peak pressure in the combustion chamber. With small throttle openings the pressures do not get as high as when the throttle is wide open. If driven moderately lower octane should be fine. I don't have an ML55 so I can't say I've tried it.

A Toyota Prius has a 13:1 compression ratio and specifies 87 octane. Higher octanes are known to cause the Prius to throw a fault code and CEL. Toyota makes this work by controlling intake valve timing to limit the charge in the combustion chamber, holding combustion pressures down to manageable levels. I do have a Prius.

If its only a matter of fuel economy then a simple experiment with each fuel and a calculation is all that is needed to make the decision.
 

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'02 ML500 (Kleeman headers, tune, AMG ML55 wheels,3.09 diffs, 3rd row seats);
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:(

What the O.P. did was demonstrate wisdom and frugality in is purchase of a high quality nearly 10 year old car. Then continues on that path of independent thought by asking about the real world fuel requirement rather than be frightened into throwing money at something he might not need.



Thats a very unconvincing unsupported statement.

High octane gasoline does not have any more energy content than regular. There are special racing fuels which are gasoline compatible with more energy content, but not the stuff at the corner gas station.

Higher compression ratios are able to thermally extract more energy from combustion but usually requires a higher octane-rated fuel. The problem isn't the compression ratio but the peak pressure in the combustion chamber. With small throttle openings the pressures do not get as high as when the throttle is wide open. If driven moderately lower octane should be fine. I don't have an ML55 so I can't say I've tried it.

A Toyota Prius has a 13:1 compression ratio and specifies 87 octane. Higher octanes are known to cause the Prius to throw a fault code and CEL. Toyota makes this work by controlling intake valve timing to limit the charge in the combustion chamber, holding combustion pressures down to manageable levels. I do have a Prius.

If its only a matter of fuel economy then a simple experiment with each fuel and a calculation is all that is needed to make the decision.
There is no place here for logic and reason!!! :)

Regards,
Jerry
 

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There is no place here for logic and reason!!! :)

Regards,
Jerry
Heh, awesome. You own a ML. Makes perfect logical sense that you shouldnt put any logical sense into fixing or running it. ;)
 

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'02 ML500 (Kleeman headers, tune, AMG ML55 wheels,3.09 diffs, 3rd row seats);
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Heh, awesome. You own a ML. Makes perfect logical sense that you shouldnt put any logical sense into fixing or running it. ;)
I think you took a shot at me, but you are so smooth, I am not sure!!LOL

Regards,
Jerry
 

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Drop some 87 octane in my old 944 turbo and you will find out why you use high octane real quick. The power of high octane lies in its ability to burn evenly hence it's not going to send your knock sensor into shock. The Toyota mentioned has a cylinder chamber specifically designed for low octane fuels, something that did not happen 10 years ago as they designed the engine to run on high octane fuel.
 

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This could be answered pretty easily by one question. That is just how does the second set of plugs behave under load. Do they still lag the trailing set or does the ignition mapping fire them simultaneously. That will have more to do with how the peak pressure impulse develops and behaves. The higher or sharper the peak the higher the propensity to see knock events given certain driving styles. If you drive it like you stole it you could knock on 91, if you drive like you don't care when you get there is slow acceleration then 87 will do the job. If no one knows that then the other would be if there is a dedicated knock engine code.

Just to give you an example piston aircraft engines are designed with 10.5 and the odd one higher. When these first were designed 130 octane was standard at the pumps. They also have big bores on the order of 5 inches plus and dual plugs. These are also air cooled and cost say $35K for a small one. So you don't want to screw them up. After the high octane went bye bye because of lead content they tested and certified "mogas" over about 5 years. Mogas is just 87 octane. So after all that testing and much doom and gloom they found no difference in reliability. Engines were not melting down or blowing the cylinders off. They found the flame front speed did not significantly change. If you are not familiar with aviation then think how advanced auto engines were around ww2 and that would be pushing it.
 

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'02 ML500 (Kleeman headers, tune, AMG ML55 wheels,3.09 diffs, 3rd row seats);
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That is just how does the second set of plugs behave under load.
That is the issue, when the engine is under (heavy) load.

The higher or sharper the peak the higher the propensity to see knock events given certain driving styles.
Yes, and the higher octane helps prevent knock

If you drive it like you stole it you could knock on 91,
It shouldn't if engine is in tune. Manufacturers use the most conservative rating, so unless the motor is wildly out of tune, it really shouldn't knock on the manufacturers recommended octane.

if you drive like you don't care when you get there is slow acceleration then 87 will do the job.
Or simply not drive it hard enough to require more octane than you put in. Mild throttle shouldn't cause the knock sensors to kick in even under 87.


@Mike
Big difference with forced induction. Ignoring technology, FI generates a lot more heat, so the use of higher octane (even going above 93 depending on modications) is usually a wise move. My old 86 944t ran fine on 93, although I did add 3-4 gallons of 100 leaded when on the track to help compensate for higher boost than stock. Never had an issue.

Regards,
Jerry
 

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I second the oppinion that u have to experiment see what works best for you.
the 91 u buy at the gas station may be old so maybe it's less than 91...
still using 87 in an engine requiring 91 may mean that you rely on the knock sensors to do their job esp under load, but maybe they are slightly out of spec too...
so they're too many variables, best to experiment with several tankfulls from whatever you have around you and judge by the returned mpg.
I understand that once in a while is good to redline an engine to clean up the deposits in and around the combustion chambers. I would do this with premium. but most of the time my truck barely sees 3k rpm. I think I'm perfectly fine with 87 for that...
 
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