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2000 mercedes-benz e320
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Discussion Starter #1
Hello,

I'm sure this discussion has been had before here, but are we able to run 89 octane in the m112 v6 in the 210 chassis?
I've always (and will continue to) used premium, but I've met lots of fellow owners that run the mid-grade. Are there any serious downfalls to the 89 octane?

Thanks!
 

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99 E430, 99 E320, 97 E300, 95 E300, 93 300D, 92 300SD, 89 560SEL, 76 300D, 76 240D plus about30 more
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On my 01 E320 I have always run 91 and I track every fill up. About 6 months ago I decided to try 87 for a while to see what would happen. I ran it probably 3 months or so and mileage was exactly the same as it was with the 91 and I could not see any reduction in power. I then moved back to 91 and it once again was the same. Bear in mind my driving with this car was not aggressive with full throttle launches or anything. If you are driving like that it might make a difference. I am still on the fence about running 91 or 87. One other point of info is these are 10:1 compression engines. We used to have some Chevy Sonic cars with the 4 cylinder (1.8L I think) engine that call for 87. Those also have a 10:1 compression ratio so I am not sure why those can run on 87 but the M112/M113 is supposed to have premium. Maybe the programming or timing is different or something, not sure.
 

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1998 E320s sedan and wagon
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1,032 Posts
My son tracked consumption in the ‘98 E320 sedan and noticed a drop in mpg with 87. Based on his commute, premium would cost $40 more a year.

Sixto
98 E320 wagon 197K miles
 

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99 E430, 99 E320, 97 E300, 95 E300, 93 300D, 92 300SD, 89 560SEL, 76 300D, 76 240D plus about30 more
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Around here I am looking at a difference of around $6 or so per tank for premium over 87. I am thinking my use of 87 might have been during the cooler months so summertime might have made a different in mileage.
 

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1998 E320 base sedan @ 160kmiles
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Around here, there is 60 cents per-gallon difference between 87 octane and 91 octane gas. Assuming 20 miles per gallon, and 10,000 miles a year, it will take 500 gallons of gas a year, and a difference of 300 dollars. I do not believe there is any difference in terms of energy conversion between regular and super provided that the car is not driven with heavy foot on the gas.
 

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1996 SL500, 2000 E430
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If the manufacturer specified Premium why mess around? Every Mercedes I've come across has demanded Premium.
 

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2002 E430 Sprt/w W211 wheels
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After all these M112 and M113s, at least the 4.3 and 5.0 have 10:1 compression ratio, not that high IMO. The PO of my car ran it on 89 for the 4 years of his ownership and it ran like a top on it when I bought it and it's no different or better when I run 91. My Honda Odyssey had that compression ratio and I used nothing but the cheapest 87, and my uncle has used the same on his 04 Ody J35 since new and no issues whatsoever. So I do believe that if you don't push the M112 and M113 hard, you will be OK on 87, but just to be safe I advice you to run at least midgrade 89 from a good gas station, in my case, I sometimes do mix midgrade and premium because of 20c or a bit more difference between the two, so I get like 3 gal of 89, and 4 gal of 91 every alternate fill up, considering I put all premium last fill-up and I have like 6 gals leftover, that gives me like 90.5 or more octane so I guess even with 90 octane, you will see no difference whatsoever and it won't be bad for the car. To conclude, look at the video below, the engine doesn't ping much with 89, pings a lot with 87, so 90 or more octane would be equal to 91 and shouldn't ping at all under full throttle uphill.

 

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1998 E320 base sedan @ 160kmiles
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6,678 Posts
After all these M112 and M113s, at least the 4.3 and 5.0 have 10:1 compression ratio, not that high IMO. The PO of my car ran it on 89 for the 4 years of his ownership and it ran like a top on it when I bought it and it's no different or better when I run 91. My Honda Odyssey had that compression ratio and I used nothing but the cheapest 87, and my uncle has used the same on his 04 Ody J35 since new and no issues whatsoever. So I do believe that if you don't push the M112 and M113 hard, you will be OK on 87, but just to be safe I advice you to run at least midgrade 89 from a good gas station, in my case, I sometimes do mix midgrade and premium because of 20c or a bit more difference between the two, so I get like 3 gal of 89, and 4 gal of 91 every alternate fill up, considering I put all premium last fill-up and I have like 6 gals leftover, that gives me like 90.5 or more octane so I guess even with 90 octane, you will see no difference whatsoever and it won't be bad for the car. To conclude, look at the video below, the engine doesn't ping much with 89, pings a lot with 87, so 90 or more octane would be equal to 91 and shouldn't ping at all under full throttle uphill.

I did the same test with my scanner and 89 octane gas. With the way I drive, I had NO knocks detected whatsoever. Only used 87 octane gas once, as no other gas was available, just after the hurricane warning. The knock sensing and analysis and adjustment takes some hundreds of milliseconds due to full electronic control of ignition timing.
 

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1996 SL500, 2000 E430
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I did the same test with my scanner and 89 octane gas. With the way I drive, I had NO knocks detected whatsoever. Only used 87 octane gas once, as no other gas was available, just after the hurricane warning. The knock sensing and analysis and adjustment takes some hundreds of milliseconds due to full electronic control of ignition timing.
mrboca - you certainly seem to know these cars better than me, but would you ever hear any knocks? The timing would be backed off as the power.

.
 

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1998 E320 base sedan @ 160kmiles
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mrboca - you certainly seem to know these cars better than me, but would you ever hear any knocks? The timing would be backed off as the power.

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You listen to the video posted. Have you heard any knocks when the timing is retarded on certain cylinders as illustrated ?. You could hear knocking if they are persistent, and beyond the timing adaptation limits. It is the knock sensors that do the "hearing" for you, on per fired cylinder basis, and the ECU signal processors analyze and adapt timing, on "per-cylinder" basis.. Note that there are knock threshold limits, and only when exceeded, the ECU takes action before the damaging knock levels are actually reached, and these values are stored to be used as part of adaptation.

The ECU also uses the knock sensor (and other) information to adapt other parameters too (dynamic adjustments to air/fuel ratio, and in some engines, changes in the boost pressure). This is not to say that you should use gas with lower octane level than the manufacturer's "requirement", as this requirement will address varying driving patterns, terrain differences, towing, differing climate conditions, altitude, etc.
 

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1982 380SEC, 2014 ML350 4Matic
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Obviously many opinions here. I own 5 vehicles, 3 of them Mercedes requiring premium. My BMW does too. Neither my old F150 or my JD lawn tractor require premium, but I run premium in them too. The pickup(carburetor) actually runs better with premium. I figure the easiest preventative maintenance is fresh oil and premium gasoline. Will save money in the long run. I know my E46 will need expensive fuel injection cleaning if you go cheap. Keep in mind that these cars are made for European gasoline with octane numbers in the mid 90s.
I also stay away from ethanol in my older cars.
 

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1998 E320 base sedan @ 160kmiles
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Obviously many opinions here. I own 5 vehicles, 3 of them Mercedes requiring premium. My BMW does too. Neither my old F150 or my JD lawn tractor require premium, but I run premium in them too. The pickup(carburetor) actually runs better with premium. I figure the easiest preventative maintenance is fresh oil and premium gasoline. Will save money in the long run. I know my E46 will need expensive fuel injection cleaning if you go cheap. Keep in mind that these cars are made for European gasoline with octane numbers in the mid 90s.
I also stay away from ethanol in my older cars.
I believe you are misinformed. European octane rating is different from the USA, and they use the RON system. The USA rating is based on (RON + MON) / 2 which is called AKI (anti-knock index). The Euro super 98 octane (RON) is roughly equivalent to 91 octane (AKI). I said roughly because MON value is not fixed. What determines the quality of the gas is not the octane rating, but the quality of additives. That is why it is important to get gas from a Tier 1 gas station. And there mostly is no real difference in terms of additives between regular and super "premium".
 
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