Premium Gas Octane Rating. What is yours?
Thread Starter
Senior Member
Joined: May 2008
Posts: 293
Likes: 0
From: Columbus, OH
2003 CLK500
Premium Gas Octane Rating. What is yours?
When I picked up my car in Phoenix and drove 1900 miles back to Ohio, I noticed a BIG difference in Octane ratings for Premium Gas. It ranged from 90 Octane to 93 Octane here in Columbus. Our Plus (midgrade) rating is 89 Octane. Due to the high gas prices, I've been mixing my fuel, half tank 89, and half 93.
Does anyone know what the Octane requirements are for our MBs?
I also would like to hear what Octane you guys (and girls) are putting in your cars.
Does anyone know what the Octane requirements are for our MBs?
I also would like to hear what Octane you guys (and girls) are putting in your cars.
MBWorld Fanatic!
Joined: Mar 2006
Posts: 4,278
Likes: 379
From: San Jose area
'19 E63S sedan
91. 90 is standard in the mountain states because the car gets less air, but anything lower than 91 at sea level will lower performance when the knock detectors retard timing.
Almost a Member!
Joined: May 2008
Posts: 38
Likes: 0
1977 6.9; 2007 CLK350
My 2007 CLK 350 calls for a 95 Research Octane Number (RON) with a 91 minimum. Our gas averages Research and Motor, and the spread is 8-10 points. Therefore, you can easily get away with running 89. It will have a RON of 93-94.
I did it for years on an NSX I was tracking and I have been using 89 in my MB and my wife's RL. There is the possibility you are not getting all the horsepower your engine can generate, but I doubt you will notice it. Further, modern engine management systems can easily deal with such a small difference. Finally, 89 is $0.10-0.20/gal cheaper than 93, which is overkill.
I haven't tried it, but I am told you can easily get away with running 87 for relatively short periods, but I don't know how short.
I did it for years on an NSX I was tracking and I have been using 89 in my MB and my wife's RL. There is the possibility you are not getting all the horsepower your engine can generate, but I doubt you will notice it. Further, modern engine management systems can easily deal with such a small difference. Finally, 89 is $0.10-0.20/gal cheaper than 93, which is overkill.
I haven't tried it, but I am told you can easily get away with running 87 for relatively short periods, but I don't know how short.
Thread Starter
Senior Member
Joined: May 2008
Posts: 293
Likes: 0
From: Columbus, OH
2003 CLK500
My 2007 CLK 350 calls for a 95 Research Octane Number (RON) with a 91 minimum. Our gas averages Research and Motor, and the spread is 8-10 points. Therefore, you can easily get away with running 89. It will have a RON of 93-94.
I did it for years on an NSX I was tracking and I have been using 89 in my MB and my wife's RL. There is the possibility you are not getting all the horsepower your engine can generate, but I doubt you will notice it. Further, modern engine management systems can easily deal with such a small difference. Finally, 89 is $0.10-0.20/gal cheaper than 93, which is overkill.
I haven't tried it, but I am told you can easily get away with running 87 for relatively short periods, but I don't know how short.
I did it for years on an NSX I was tracking and I have been using 89 in my MB and my wife's RL. There is the possibility you are not getting all the horsepower your engine can generate, but I doubt you will notice it. Further, modern engine management systems can easily deal with such a small difference. Finally, 89 is $0.10-0.20/gal cheaper than 93, which is overkill.
I haven't tried it, but I am told you can easily get away with running 87 for relatively short periods, but I don't know how short.
Almost a Member!
Joined: May 2008
Posts: 38
Likes: 0
1977 6.9; 2007 CLK350
I am saying you can use 100% 89 without any problems, assuming your car has the same requirements as mine, 95 RON with a 91 minimum. Most 89 you are likely to encounter in the US will be at least 91 RON and probably 93 or 94.
MBWorld Fanatic!
Joined: Mar 2006
Posts: 1,627
Likes: 5
From: West Virginia
2001 E320 RWD - Brilliant Silver/Ash: 100,000+
Trending Topics
MB World Stories
The Best of Mercedes & AMG
7 Craziest Things AMG Gas Ever Built
Verdad Gallardo
New Electric Mercedes-AMG GT 4-Door Coupe Unveiled: 10 Things You Need to Know
Verdad Gallardo
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)
Verdad Gallardo
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
Almost a Member!
Joined: May 2008
Posts: 38
Likes: 0
1977 6.9; 2007 CLK350
The 89 we see on the pump has a RON of 93-94 or maybe more, and the 93 is 97-98. A 50/50 blend would have a RON of 95-96, which would be more than enough for my car. However, I have never had any problem running 89 in any high performance car requiring "premium".
I recommend the OP at least try a couple of tanks of straight 89. I doubt he will notice any difference, but if he does he can go back to the 50/50 blend.
Thread Starter
Senior Member
Joined: May 2008
Posts: 293
Likes: 0
From: Columbus, OH
2003 CLK500
I might try 89 on a couple fills, as long as it won't damage anything. That could save me a lot of money in the long run.
Senior Member
Joined: Sep 2004
Posts: 315
Likes: 2
From: Orlando, FL
2008 E350
Just to use round numbers, say the price difference is .20 per gallon on 4.00 per gallon. That's a 5 percent savings. If you average 25 miles per gallons on premium and your mileage goes down 1.25 mpg on 89, you break even. Any more mileage loss and you are actually spending more for gas when you use 89.
Why anyone would buy a Mercedes and put anything other than premium makes no sense. You have invested in a well engineered car which functions best on premium fuel. Anything less actually costs you more money. You're talking about saving pennies. In absolute terms, it seems like more, but it really isn't when you figure it in percentages.
This scenario is subject to change as the price differential goes up. But the price differential would have to increase substantially for there to be any savings. But as the overall price goes up, so the differential also needs to increase by a larger factor in order for there to be a savings in using anything other than premium.
I hope this helps.
Almost a Member!
Joined: May 2008
Posts: 38
Likes: 0
1977 6.9; 2007 CLK350
Note, I am not saying you cannot modify an engine to get better performance on higher octane gas. I am talking strictly out of the box.
I have driven many different cars over the past 50 years and tried "better" fuels. I never found that it made a measurable difference on the road. The one exception was when my 1977 6.9 developed a vacuum leak and started to knock on regular. I had to run 89 until I got it fixed. However, running 89 did not improve mileage or performance. It just stopped the knocking.
Thread Starter
Senior Member
Joined: May 2008
Posts: 293
Likes: 0
From: Columbus, OH
2003 CLK500
If you are running the correct octane, increasing it will not help in performance or mileage. Some people think higher octane gas then required by the manufacturer will improve engine performance. It won't. It just wastes money, and nobody, not even an MB owner, should do that.
I'm not saying that I'm broke, otherwise I wouldn't have bought a MB. But I'm just the type of person that will bend over to pick up a penny whenever I see one. Pennies add up! Last year, my saved change added up to over $880, which paid for a weekend away for my wife and I in Chicago. This year so far, I've saved over $750 in change, which will contribute to our upcoming vacation in the Keys.
Plus, the more money I save, the more I can MOD my Benz!
MBWorld Fanatic!
Joined: Sep 2007
Posts: 7,136
Likes: 5
Corrolla
[QUOTE=Discgolfer74;2855091]I agree. Granted, I would only save about $1.60 per fill-up, which is no big deal. But over the course of a year, that could add up to $100. I drive 200 miles per week just to work and back, which doesn't included weekend trips to play discgolf, or to visit the in-laws.
I'm not saying that I'm broke, otherwise I wouldn't have bought a MB. But I'm just the type of person that will bend over to pick up a penny whenever I see one. Pennies add up! Last year, my saved change added up to over $880, which paid for a weekend away for my wife and I in Chicago. This year so far, I've saved over $750 in change, which will contribute to our upcoming vacation in the Keys.
Plus, the more money I save, the more I can MOD my Benz![/QUOTE]
Thats what I do too...anyway back to the gas thigns I cant find no 93 octane around here so I have to use a premium 91.
I'm not saying that I'm broke, otherwise I wouldn't have bought a MB. But I'm just the type of person that will bend over to pick up a penny whenever I see one. Pennies add up! Last year, my saved change added up to over $880, which paid for a weekend away for my wife and I in Chicago. This year so far, I've saved over $750 in change, which will contribute to our upcoming vacation in the Keys.
Plus, the more money I save, the more I can MOD my Benz![/QUOTE]
Thats what I do too...anyway back to the gas thigns I cant find no 93 octane around here so I have to use a premium 91.
Thread Starter
Senior Member
Joined: May 2008
Posts: 293
Likes: 0
From: Columbus, OH
2003 CLK500
Member
Joined: Jun 2007
Posts: 128
Likes: 0
07 Clk 550
Higher octane produce less knockings, which means more power only if the car is prepped for that.
As GGM said, MB recommended it for a reason whether it maybe for a profit or real advice. This is comparable to engine oil. Why don't you save a little and get cheaper oil than use recommended synthetic one or downgrade cheaply made tires than use performance tires? Why do some people prefer certain manufacturers to others? Gas might be gas in the end, but it depends on how the company refined it. Higher octane is used for high performance cars because it produce less knocks, which means it can run on a more aggressive set-up/tune; therefore, the car produces more power. Sure you can run lower octane, but you won't be at 100% power most of the time. Most people who drive their car don't really care much about the specifics. For car fanatics, these little detail can be major. I for one will never put anything that is less than 93 octane. Then again, it's the owner's car, and he/she can do whatever he/she wants to it.
As GGM said, MB recommended it for a reason whether it maybe for a profit or real advice. This is comparable to engine oil. Why don't you save a little and get cheaper oil than use recommended synthetic one or downgrade cheaply made tires than use performance tires? Why do some people prefer certain manufacturers to others? Gas might be gas in the end, but it depends on how the company refined it. Higher octane is used for high performance cars because it produce less knocks, which means it can run on a more aggressive set-up/tune; therefore, the car produces more power. Sure you can run lower octane, but you won't be at 100% power most of the time. Most people who drive their car don't really care much about the specifics. For car fanatics, these little detail can be major. I for one will never put anything that is less than 93 octane. Then again, it's the owner's car, and he/she can do whatever he/she wants to it.
Last edited by aznAMG07; May 30, 2008 at 07:59 PM.
Thread Starter
Senior Member
Joined: May 2008
Posts: 293
Likes: 0
From: Columbus, OH
2003 CLK500
Higher octane produce less knockings, which means more power only if the car is prepped for that.
As GGM said, MB recommended it for a reason whether it maybe for a profit or real advice. This is comparable to engine oil. Why don't you save a little and get cheaper oil than use recommended synthetic one or downgrade cheaply made tires than use performance tires? Why do some people prefer certain manufacturers to others? Gas might be gas in the end, but it depends on how the company refined it. Higher octane is used for high performance cars because it produce less knocks, which means it can run on a more aggressive set-up/tune; therefore, the car produces more power. Sure you can run lower octane, but you won't be at 100% power most of the time. Most people who drive their car don't really care much about the specifics. For car fanatics, these little detail can be major. I for one will never put anything that is less than 93 octane. Then again, it's the owner's car, and he/she can do whatever he/she wants to it.
As GGM said, MB recommended it for a reason whether it maybe for a profit or real advice. This is comparable to engine oil. Why don't you save a little and get cheaper oil than use recommended synthetic one or downgrade cheaply made tires than use performance tires? Why do some people prefer certain manufacturers to others? Gas might be gas in the end, but it depends on how the company refined it. Higher octane is used for high performance cars because it produce less knocks, which means it can run on a more aggressive set-up/tune; therefore, the car produces more power. Sure you can run lower octane, but you won't be at 100% power most of the time. Most people who drive their car don't really care much about the specifics. For car fanatics, these little detail can be major. I for one will never put anything that is less than 93 octane. Then again, it's the owner's car, and he/she can do whatever he/she wants to it.
Senior Member
Joined: Sep 2004
Posts: 315
Likes: 2
From: Orlando, FL
2008 E350
If you are running the correct octane, increasing it will not help in performance or mileage. Some people think higher octane gas then required by the manufacturer will improve engine performance. It won't. It just wastes money, and nobody, not even an MB owner, should do that
Note, I am not saying you cannot modify an engine to get better performance on higher octane gas. I am talking strictly out of the box.
I have driven many different cars over the past 50 years and tried "better" fuels. I never found that it made a measurable difference on the road. The one exception was when my 1977 6.9 developed a vacuum leak and started to knock on regular. I had to run 89 until I got it fixed. However, running 89 did not improve mileage or performance. It just stopped the knocking.
Note, I am not saying you cannot modify an engine to get better performance on higher octane gas. I am talking strictly out of the box.
I have driven many different cars over the past 50 years and tried "better" fuels. I never found that it made a measurable difference on the road. The one exception was when my 1977 6.9 developed a vacuum leak and started to knock on regular. I had to run 89 until I got it fixed. However, running 89 did not improve mileage or performance. It just stopped the knocking.
My experience with gas mileage comes from my wife's Chrysler 300 with the 3.5 liter engine. She used to run regular in it because it was cheaper. I then tried the recommended midgrade and compared the mpg she was getting with regular vs. the mpg with the midgrade. She got about a 10% increase in mpg vs the less than 10% price differential between regular and midgrade. So she is actually saving money by spending more for midgrade.
I have never tested using a lower grade gasoline in my E350. I get better mileage than she does and I don't want to mess that up.
I believe manufacturers make recommendations based on the engineering of the engine. I don't think there is any ulterior motive.
Just sharing my experience. YMMV
Almost a Member!
Joined: May 2008
Posts: 38
Likes: 0
1977 6.9; 2007 CLK350
I never said to use higher octane than recommended. Mercedes recommends "premium." Here in Orlando, "premium" is 93 octane. In my travels, sometimes "premium" is 91. Either way, I use "premium."
My experience with gas mileage comes from my wife's Chrysler 300 with the 3.5 liter engine. She used to run regular in it because it was cheaper. I then tried the recommended midgrade and compared the mpg she was getting with regular vs. the mpg with the midgrade. She got about a 10% increase in mpg vs the less than 10% price differential between regular and midgrade. So she is actually saving money by spending more for midgrade.
My experience with gas mileage comes from my wife's Chrysler 300 with the 3.5 liter engine. She used to run regular in it because it was cheaper. I then tried the recommended midgrade and compared the mpg she was getting with regular vs. the mpg with the midgrade. She got about a 10% increase in mpg vs the less than 10% price differential between regular and midgrade. So she is actually saving money by spending more for midgrade.
As for mileage, my CLK gets 30, believe it or not, running 75 on I-81 through the Shenandoah Valley but only about 22 in the mountains of Western PA. If I could actually find 90 or 91 pump octane, I wouldn't expect to do much better.
The 6.9 seems to get 10 city and 14 highway no matter what I run, which suggests 87 actually is about right. Can you believe that, 10/14!! What a waste.
