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Now that these cars are older what gasoline grade of fuel do currently use?


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W221 & Audio Moderator
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Discussion Starter #1
Do you still run the manufacturer's recommended premium 91+ R+2/M octane fuel, or are you comfortable and had good luck with lesser grade fuels?

This is not to start a heated discussion as some are very opinionated on this topic, (such as what oil they use!) so please be respectful and any comments on any differences you have noted if you have chosen to try a grade other than the manufacturer's recommended fuel would be interesting.
 

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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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Cheap gas fouls spark plugs and creates a lot of carbon build up. Saving $1.20 at the pump can mean thousands in repair costs down the line.

My E320 has 272k miles on it. When I bought the car from the PO she made a point to tell me that she NEVER, EVER, during the life of car from 2005 until now, used cheap gas. She literally went out of her way to tell me that.

Looking at the car service record and seeing the condition of the car, I can determine that line to be a complete lie.

I go by manufacturer specification.
 

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2002 E55 AMG Sedan
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1,159 Posts
I put in premium. Over here that is 93 octane. I do this because I want full power from the engine and I want the best MPG that I can get. Using anything less than 91 octane would hurt these two things and I'm not cool with that on my car.
 

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w163 02 ML500 W210 97 E50Amg w202 99 C230K w124 - need more space, time to build again
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ditto with illstplaya.
93+ north of the 49th parallel.
 

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1996 SL500, 2000 E430
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What does the age of the car have to do with using a lower octane? My 2000 E430 has used Chevron Supreme since new. The engine shows it.

Of course with knock sensors these cars can run on regular but less power, less fuel economy.
 

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W221 & Audio Moderator
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Discussion Starter #6
Lower cost to purchase = lower perceived value = no need for premium priced gas in inexpensive car could be how some owners train of thought is.
 

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W221 & Audio Moderator
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Discussion Starter #8
The reality is that the ECUs in any modern (1998+) Mercedes-Benz has the ignition timing set to always start at "Base Value" so it is expecting poor fuel when started. It gradually increases the timing as you drive after it determines it does not knock as a result. This process occurs every engine start.
 

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1998 E320 base sedan @ 160kmiles
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What does the age of the car have to do with using a lower octane? My 2000 E430 has used Chevron Supreme since new. The engine shows it.

Of course with knock sensors these cars can run on regular but less power, less fuel economy.
Does the higher octane gas have more energy than the lower octane one (fluid ounce-by-ounce) ?
 

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E320/E250 Bluetec Ford F350 6.7l
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Lower octane gas will actually increase mpg.
The car will retard ignition, so you won't be able to accelerate hardly. But then there is limit how timely computer can retard ignition, so some pinging will occur here and there. That has potential to damage the engine, but might take tens of thousands miles to show.
Than why buy car with big engine and lower its performance, when 3-cylinders cars are available?
 

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2006 E350, 2007 SL550
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Do you still run the manufacturer's recommended premium 91+ R+2/M octane fuel, or are you comfortable and had good luck with lesser grade fuels?

This is not to start a heated discussion as some are very opinionated on this topic, (such as what oil they use!) so please be respectful and any comments on any differences you have noted if you have chosen to try a grade other than the manufacturer's recommended fuel would be interesting.
 

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2006 E350, 2007 SL550
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Have owned Mercedes for over 30 years. Driving on flat, sea level roads, I burn Regular Unleaded in all but my SL550. Waste of money to go premium octane, but always buy high quality fuel.
 

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2008 CLK-550
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Here in Texas with my '06 CLK-550, I run on 93 octane gasoline. It's not that high a cost for me as the price has been hovering around 2.50-2.70 per gallon and, while it's a daily drive, I don't travel that far so wind up filling up every two weeks or so.
 

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Do you still run the manufacturer's recommended premium 91+ R+2/M octane fuel, or are you comfortable and had good luck with lesser grade fuels?

This is not to start a heated discussion as some are very opinionated on this topic, (such as what oil they use!) so please be respectful and any comments on any differences you have noted if you have chosen to try a grade other than the manufacturer's recommended fuel would be interesting.
,.........I own a 2003 sl500..Designo edition..I run nothing but 93 octane from Sam's Club here in Texas...$2:30+ price.. cheapest good premium I found anywhere around here....Only 302 hp..but I have been told by MB mechanics that premium fuel helps keep engine cleaner timing and power at peak, and cheaper fuel in a car required to run on premium messes with the exhaust system and bad on o2 sensors and catalytic converters..when that check engine light comes on after running cheaper. Low octane fuel, the cost of repairs will be a lot higher than that tank fill up every week or two...Car dealers say must or recommend what fuel or octane to run on...they don't just say this to make the oil companies richer.lol..If you don't want to run premium simply look for a vehicle that does not have to run it.. thanks
 

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1999 E320, 2003 E320 Wagon, 2005 C230K SS, 2010 Accord LX w Eibach & Koni FSD's
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Here in Northern California, our connoisseur's blend near where I live is going for $3.45-$3.89 a gallon.

Regular at Costco is currently $3.06......so I guess there might be some temptation for those with beaters.

That's almost $15 difference if you have to fill a tank with 18 gallons.
 

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1996 SL500, 2000 E430
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Have you had your engine apart to see the internals/carbon/pistons/valves?
Me? I have used Chevron Supreme with Techron for decades. I once pulled the head of my late 300E at 155,000 miles, and there wasn't even carbon on the piston tops.

As far as the E430, havn't pulled the engine apart (no need to), but my shop friend pulled a spark plug to check (at 110,000 miles and 20 years, never changed) and the plug, while a bit worn, was "still OK".

Sure the car could run regular but at a noticeable loss of power and mileage. Because the timing being retarded.
 

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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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Regular gas creates a lot of carbon build up, to the point where it will plug up the secondary air passageway in the head and foul up the spark plugs.

I should know, I'm dealing with both of these from the &#&@* previous owner.
 

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2000 E 320 Wagon + 2002 ML 500 SUV
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I switch it up. When I want more power & top performance like towing a load, I go premium.
Otherwise, standard grade.

IMHO, of equal consideration is the length of our average drives. With the V-8 in our ML500 it really appreciates getting fully hot on a 50+ mile highway cruise, which I see precious little of.

Just pulled a small cargo trailer to Indy - 900 miles and upon arriving I noted how much smoother, happier and more powerfully the engine performed after that LOOONG highway cruise / pull !

There's a lot of talk of clogged Catalytic converters and I now attribute that in our case to excessively short trips - running our 3 girls all associated errands all over our small town with frequent stops.
Too many trips, too many cycles, so combustion by products build up - but not blown out.

Using Premium more often couldn't hurt, that's for sure.

I just paid $ 2.01 for regular unleaded, once we drop below the $2 threshold, I may opt for Premium more often. I'd be curious if anyone has gas prices lower than that, as of now.

Cheers - David in Texas
 

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Premium Member
1998 E320 base sedan @ 160kmiles
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Here in Palm Beach county, the difference between regular and premium is about 60 cents. In Broward County gas is a bit cheaper as Palm Beach imposes special surcharge tax on gas, but the difference is about the same ($2.39 for regular, $2.89 for 89 octane, and $2.99 for premium , 91 octane).. If you put 20 gallons into the tank, the difference will be $12, which is not pocket change. Then again, FL is flat :).
 
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